diff --git a/tests/phpunit/tests/file.php b/tests/phpunit/tests/file.php
index 9a29e4e67669a..0d7ad78a150e4 100644
--- a/tests/phpunit/tests/file.php
+++ b/tests/phpunit/tests/file.php
@@ -15,85 +15,6 @@ public function set_up() {
 		$this->dir = untrailingslashit( get_temp_dir() );
 	}
 
-	/**
-	 * @group plugins
-	 * @group themes
-	 */
-	public function test_get_file_data() {
-		$theme_headers = array(
-			'Name'        => 'Theme Name',
-			'ThemeURI'    => 'Theme URI',
-			'Description' => 'Description',
-			'Version'     => 'Version',
-			'Author'      => 'Author',
-			'AuthorURI'   => 'Author URI',
-		);
-
-		$actual = get_file_data( DIR_TESTDATA . '/themedir1/default/style.css', $theme_headers );
-
-		$expected = array(
-			'Name'        => 'WordPress Default',
-			'ThemeURI'    => 'http://wordpress.org/',
-			'Description' => 'The default WordPress theme based on the famous <a href="http://binarybonsai.com/kubrick/">Kubrick</a>.',
-			'Version'     => '1.6',
-			'Author'      => 'Michael Heilemann',
-			'AuthorURI'   => 'http://binarybonsai.com/',
-		);
-
-		$this->assertNotEmpty( $actual );
-
-		foreach ( $actual as $header => $value ) {
-			$this->assertSame( $expected[ $header ], $value, $header );
-		}
-	}
-
-	/**
-	 * @ticket 19854
-	 * @group plugins
-	 * @group themes
-	 */
-	public function test_get_file_data_with_cr_line_endings() {
-		$headers = array(
-			'SomeHeader'  => 'Some Header',
-			'Description' => 'Description',
-			'Author'      => 'Author',
-		);
-
-		$actual   = get_file_data( DIR_TESTDATA . '/formatting/file-header-cr-line-endings.php', $headers );
-		$expected = array(
-			'SomeHeader'  => 'Some header value!',
-			'Description' => 'This file is using CR line endings for a testcase.',
-			'Author'      => 'A Very Old Mac',
-		);
-
-		$this->assertNotEmpty( $actual );
-
-		foreach ( $actual as $header => $value ) {
-			$this->assertSame( $expected[ $header ], $value, $header );
-		}
-	}
-
-	/**
-	 * @ticket 47186
-	 * @group plugins
-	 * @group themes
-	 */
-	public function test_get_file_data_with_php_open_tag_prefix() {
-		$headers = array(
-			'TemplateName' => 'Template Name',
-		);
-
-		$actual   = get_file_data( DIR_TESTDATA . '/formatting/file-header-php-open-tag-prefix.php', $headers );
-		$expected = array(
-			'TemplateName' => 'Something',
-		);
-
-		$this->assertNotEmpty( $actual );
-
-		foreach ( $actual as $header => $value ) {
-			$this->assertSame( $expected[ $header ], $value, $header );
-		}
-	}
 
 	private function is_unique_writable_file( $path, $filename ) {
 		$fullpath = $path . DIRECTORY_SEPARATOR . $filename;
diff --git a/tests/phpunit/tests/functions.php b/tests/phpunit/tests/functions.php
deleted file mode 100644
index b6080da780ba8..0000000000000
--- a/tests/phpunit/tests/functions.php
+++ /dev/null
@@ -1,2301 +0,0 @@
-<?php
-
-/**
- * @group functions
- */
-class Tests_Functions extends WP_UnitTestCase {
-	public function test_wp_parse_args_object() {
-		$x        = new MockClass();
-		$x->_baba = 5;
-		$x->yZ    = 'baba'; // phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
-		$x->a     = array( 5, 111, 'x' );
-		$this->assertSame(
-			array(
-				'_baba' => 5,
-				'yZ'    => 'baba',
-				'a'     => array( 5, 111, 'x' ),
-			),
-			wp_parse_args( $x )
-		);
-		$y = new MockClass();
-		$this->assertSame( array(), wp_parse_args( $y ) );
-	}
-
-	public function test_wp_parse_args_array() {
-		// Arrays.
-		$a = array();
-		$this->assertSame( array(), wp_parse_args( $a ) );
-		$b = array(
-			'_baba' => 5,
-			'yZ'    => 'baba',
-			'a'     => array( 5, 111, 'x' ),
-		);
-		$this->assertSame(
-			array(
-				'_baba' => 5,
-				'yZ'    => 'baba',
-				'a'     => array( 5, 111, 'x' ),
-			),
-			wp_parse_args( $b )
-		);
-	}
-
-	public function test_wp_parse_args_defaults() {
-		$x        = new MockClass();
-		$x->_baba = 5;
-		$x->yZ    = 'baba'; // phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
-		$x->a     = array( 5, 111, 'x' );
-		$d        = array( 'pu' => 'bu' );
-		$this->assertSame(
-			array(
-				'pu'    => 'bu',
-				'_baba' => 5,
-				'yZ'    => 'baba',
-				'a'     => array( 5, 111, 'x' ),
-			),
-			wp_parse_args( $x, $d )
-		);
-		$e = array( '_baba' => 6 );
-		$this->assertSame(
-			array(
-				'_baba' => 5,
-				'yZ'    => 'baba',
-				'a'     => array( 5, 111, 'x' ),
-			),
-			wp_parse_args( $x, $e )
-		);
-	}
-
-	public function test_wp_parse_args_other() {
-		$b = true;
-		wp_parse_str( $b, $s );
-		$this->assertSame( $s, wp_parse_args( $b ) );
-		$q = 'x=5&_baba=dudu&';
-		wp_parse_str( $q, $ss );
-		$this->assertSame( $ss, wp_parse_args( $q ) );
-	}
-
-	/**
-	 * @ticket 30753
-	 */
-	public function test_wp_parse_args_boolean_strings() {
-		$args = wp_parse_args( 'foo=false&bar=true' );
-		$this->assertIsString( $args['foo'] );
-		$this->assertIsString( $args['bar'] );
-	}
-
-	/**
-	 * @ticket 35972
-	 */
-	public function test_bool_from_yn() {
-		$this->assertTrue( bool_from_yn( 'Y' ) );
-		$this->assertTrue( bool_from_yn( 'y' ) );
-		$this->assertFalse( bool_from_yn( 'n' ) );
-	}
-
-	public function test_path_is_absolute() {
-		$absolute_paths = array(
-			'/',
-			'/foo/',
-			'/foo',
-			'/FOO/bar',
-			'/foo/bar/',
-			'/foo/../bar/',
-			'\\WINDOWS',
-			'C:\\',
-			'C:\\WINDOWS',
-			'\\\\sambashare\\foo',
-		);
-		foreach ( $absolute_paths as $path ) {
-			$this->assertTrue( path_is_absolute( $path ), "path_is_absolute('$path') should return true" );
-		}
-	}
-
-	public function test_path_is_not_absolute() {
-		$relative_paths = array(
-			'',
-			'.',
-			'..',
-			'../foo',
-			'../',
-			'../foo.bar',
-			'foo/bar',
-			'foo',
-			'FOO',
-			'..\\WINDOWS',
-		);
-		foreach ( $relative_paths as $path ) {
-			$this->assertFalse( path_is_absolute( $path ), "path_is_absolute('$path') should return false" );
-		}
-	}
-
-	/**
-	 * Tests path_join().
-	 *
-	 * @ticket 55897
-	 * @dataProvider data_path_join
-	 */
-	public function test_path_join( $base, $path, $expected ) {
-		$this->assertSame( $expected, path_join( $base, $path ) );
-	}
-
-	/**
-	 * Data provider for test_path_join().
-	 *
-	 * @return string[][]
-	 */
-	public function data_path_join() {
-		return array(
-			// Absolute paths.
-			'absolute path should return path' => array(
-				'base'     => 'base',
-				'path'     => '/path',
-				'expected' => '/path',
-			),
-			'windows path with slashes'        => array(
-				'base'     => 'base',
-				'path'     => '//path',
-				'expected' => '//path',
-			),
-			'windows path with backslashes'    => array(
-				'base'     => 'base',
-				'path'     => '\\\\path',
-				'expected' => '\\\\path',
-			),
-			// Non-absolute paths.
-			'join base and path'               => array(
-				'base'     => 'base',
-				'path'     => 'path',
-				'expected' => 'base/path',
-			),
-			'strip trailing slashes in base'   => array(
-				'base'     => 'base///',
-				'path'     => 'path',
-				'expected' => 'base/path',
-			),
-			'empty path'                       => array(
-				'base'     => 'base',
-				'path'     => '',
-				'expected' => 'base/',
-			),
-			'empty base'                       => array(
-				'base'     => '',
-				'path'     => 'path',
-				'expected' => '/path',
-			),
-			'empty path and base'              => array(
-				'base'     => '',
-				'path'     => '',
-				'expected' => '/',
-			),
-		);
-	}
-
-	/**
-	 * @ticket 33265
-	 * @ticket 35996
-	 *
-	 * @dataProvider data_wp_normalize_path
-	 */
-	public function test_wp_normalize_path( $path, $expected ) {
-		$this->assertSame( $expected, wp_normalize_path( $path ) );
-	}
-
-	public function data_wp_normalize_path() {
-		return array(
-			// Windows paths.
-			array( 'C:\\www\\path\\', 'C:/www/path/' ),
-			array( 'C:\\www\\\\path\\', 'C:/www/path/' ),
-			array( 'c:/www/path', 'C:/www/path' ),
-			array( 'c:\\www\\path\\', 'C:/www/path/' ), // Uppercase drive letter.
-			array( 'c:\\\\www\\path\\', 'C:/www/path/' ),
-			array( '\\\\Domain\\DFSRoots\\share\\path\\', '//Domain/DFSRoots/share/path/' ),
-			array( '\\\\Server\\share\\path', '//Server/share/path' ),
-			array( '\\\\Server\\share', '//Server/share' ),
-
-			// Linux paths.
-			array( '/www/path/', '/www/path/' ),
-			array( '/www/path/////', '/www/path/' ),
-			array( '/www/path', '/www/path' ),
-
-			// PHP stream wrappers.
-			array( 'php://input', 'php://input' ),
-			array( 'http://example.com//path.ext', 'http://example.com/path.ext' ),
-			array( 'file://c:\\www\\path\\', 'file://C:/www/path/' ),
-
-			// Edge cases.
-			array( '', '' ), // Empty string should return empty string.
-			array( 123, '123' ), // Integer should be cast to string.
-		);
-	}
-
-	/**
-	 * Tests that wp_normalize_path() works with objects that have __toString().
-	 *
-	 * This is important because the function uses a static cache, and the input
-	 * must be cast to string before being used as an array key.
-	 *
-	 * @ticket 64538
-	 */
-	public function test_wp_normalize_path_with_stringable_object() {
-		$file_info = new SplFileInfo( '/var/www/html\\test' );
-
-		$this->assertSame( '/var/www/html/test', wp_normalize_path( $file_info ) );
-	}
-
-	/**
-	 * Tests that wp_normalize_path() returns consistent results on repeated calls.
-	 *
-	 * The function uses a static cache, so this verifies cache behavior.
-	 *
-	 * @ticket 64538
-	 */
-	public function test_wp_normalize_path_returns_consistent_results() {
-		$path = 'C:\\www\\path\\';
-
-		$first_call  = wp_normalize_path( $path );
-		$second_call = wp_normalize_path( $path );
-		$third_call  = wp_normalize_path( $path );
-
-		$this->assertSame( $first_call, $second_call, 'Second call should return same result as first.' );
-		$this->assertSame( $second_call, $third_call, 'Third call should return same result as second.' );
-		$this->assertSame( 'C:/www/path/', $first_call, 'Normalized path should match expected value.' );
-	}
-
-	/**
-	 * Tests that wp_normalize_path() static cache stores results.
-	 *
-	 * @ticket 64538
-	 */
-	public function test_wp_normalize_path_static_cache() {
-		$path     = '/var/www/cache-test\\subdir\\';
-		$expected = '/var/www/cache-test/subdir/';
-
-		$result = wp_normalize_path( $path );
-		$this->assertSame( $expected, $result );
-
-		$reflection  = new ReflectionFunction( 'wp_normalize_path' );
-		$static_vars = $reflection->getStaticVariables();
-
-		$this->assertArrayHasKey( 'cache', $static_vars, 'Static cache array should exist.' );
-		$this->assertArrayHasKey( $path, $static_vars['cache'], 'Cache should contain the normalized path.' );
-		$this->assertSame( $expected, $static_vars['cache'][ $path ], 'Cached value should match the expected normalized path.' );
-	}
-
-	public function test_wp_unique_filename() {
-
-		$testdir = DIR_TESTDATA . '/images/';
-
-		// Confidence check.
-		$this->assertSame( 'abcdefg.png', wp_unique_filename( $testdir, 'abcdefg.png' ), 'Test non-existing file, file name should be unchanged.' );
-
-		// Ensure correct images exist.
-		$this->assertFileExists( $testdir . 'test-image.png', 'Test image does not exist' );
-		$this->assertFileDoesNotExist( $testdir . 'test-image-1.png' );
-
-		// Check number is appended if file already exists.
-		$this->assertSame( 'test-image-1.png', wp_unique_filename( $testdir, 'test-image.png' ), 'File name not unique, number not appended.' );
-
-		// Check file with uppercase extension.
-		$this->assertSame( 'test-image-1.png', wp_unique_filename( $testdir, 'test-image.PNG' ), 'File name with uppercase extension not unique, number not appended.' );
-
-		// Check file name with already added number.
-		$this->assertSame( 'test-image-2-1.gif', wp_unique_filename( $testdir, 'test-image-2.gif' ), 'File name not unique, number not appended correctly.' );
-
-		// Check special chars.
-		$this->assertSame( 'testtest-image.png', wp_unique_filename( $testdir, 'testtést-imagé.png' ), 'Filename with special chars failed' );
-
-		// Check special chars with potential conflicting name.
-		$this->assertSame( 'test-image-1.png', wp_unique_filename( $testdir, 'tést-imagé.png' ), 'Filename with special chars failed' );
-
-		// Check with single quotes in name (somehow).
-		$this->assertSame( 'abcdefgh.png', wp_unique_filename( $testdir, "abcdefg'h.png" ), 'File with quote failed' );
-
-		// Check with double quotes in name (somehow).
-		$this->assertSame( 'abcdefgh.png', wp_unique_filename( $testdir, 'abcdefg"h.png' ), 'File with quote failed' );
-
-		// Test crazy name (useful for regression tests).
-		$this->assertSame( '12af34567890@.^_qwerty-fghjkl-zx.png', wp_unique_filename( $testdir, '12%af34567890#~!@#$..%^&*()|_+qwerty  fgh`jkl zx<>?:"{}[]="\'/?.png' ), 'Failed crazy file name' );
-
-		// Test slashes in names.
-		$this->assertSame( 'abcdefg.png', wp_unique_filename( $testdir, 'abcde\fg.png' ), 'Slash not removed' );
-		$this->assertSame( 'abcdefg.png', wp_unique_filename( $testdir, 'abcde\\fg.png' ), 'Double slashed not removed' );
-		$this->assertSame( 'abcdefg.png', wp_unique_filename( $testdir, 'abcde\\\fg.png' ), 'Triple slashed not removed' );
-	}
-
-	/**
-	 * @ticket 42437
-	 */
-	public function test_unique_filename_with_dimension_like_filename() {
-		$testdir = DIR_TESTDATA . '/images/';
-
-		add_filter( 'upload_dir', array( $this, 'upload_dir_patch_basedir' ) );
-
-		// Test collision with "dimension-like" original filename.
-		$this->assertSame( 'one-blue-pixel-100x100-1.png', wp_unique_filename( $testdir, 'one-blue-pixel-100x100.png' ) );
-		// Test collision with existing sub-size filename.
-		// Existing files: one-blue-pixel-100x100.png, one-blue-pixel-1-100x100.png.
-		$this->assertSame( 'one-blue-pixel-2.png', wp_unique_filename( $testdir, 'one-blue-pixel.png' ) );
-		// Same as above with upper case extension.
-		$this->assertSame( 'one-blue-pixel-2.png', wp_unique_filename( $testdir, 'one-blue-pixel.PNG' ) );
-
-		remove_filter( 'upload_dir', array( $this, 'upload_dir_patch_basedir' ) );
-	}
-
-	// Callback to patch "basedir" when used in `wp_unique_filename()`.
-	public function upload_dir_patch_basedir( $upload_dir ) {
-		$upload_dir['basedir'] = DIR_TESTDATA . '/images/';
-		return $upload_dir;
-	}
-
-	/**
-	 * @ticket 53668
-	 */
-	public function test_wp_unique_filename_with_additional_image_extension() {
-		$testdir = DIR_TESTDATA . '/images/';
-
-		add_filter( 'upload_dir', array( $this, 'upload_dir_patch_basedir' ) );
-
-		// Set conversions for uploaded images.
-		add_filter( 'image_editor_output_format', array( $this, 'image_editor_output_format_handler' ) );
-
-		// Ensure the test images exist.
-		$this->assertFileExists( $testdir . 'test-image-1-100x100.jpg', 'test-image-1-100x100.jpg does not exist' );
-		$this->assertFileExists( $testdir . 'test-image-2.gif', 'test-image-2.gif does not exist' );
-		$this->assertFileExists( $testdir . 'test-image-3.jpg', 'test-image-3.jpg does not exist' );
-		$this->assertFileExists( $testdir . 'test-image-4.png', 'test-image-4.png does not exist' );
-
-		// Standard test: file does not exist and there are no possible intersections with other files.
-		$this->assertSame(
-			'abcdef.png',
-			wp_unique_filename( $testdir, 'abcdef.png' ),
-			'The abcdef.png, abcdef.gif, and abcdef.jpg images do not exist. The file name should not be changed.'
-		);
-
-		// Actual clash recognized.
-		$this->assertSame(
-			'canola-1.jpg',
-			wp_unique_filename( $testdir, 'canola.jpg' ),
-			'The canola.jpg image exists. The file name should be unique.'
-		);
-
-		// Same name with different extension and the image will be converted.
-		$this->assertSame(
-			'canola-1.png',
-			wp_unique_filename( $testdir, 'canola.png' ),
-			'The canola.jpg image exists. Uploading canola.png that will be converted to canola.jpg should produce unique file name.'
-		);
-
-		// Same name with different uppercase extension and the image will be converted.
-		$this->assertSame(
-			'canola-1.png',
-			wp_unique_filename( $testdir, 'canola.PNG' ),
-			'The canola.jpg image exists. Uploading canola.PNG that will be converted to canola.jpg should produce unique file name.'
-		);
-
-		// Actual clash with several images with different extensions.
-		$this->assertSame(
-			'test-image-5.png',
-			wp_unique_filename( $testdir, 'test-image.png' ),
-			'The test-image.png, test-image-1-100x100.jpg, test-image-2.gif, test-image-3.jpg, and test-image-4.png images exist.' .
-			'All of them may clash when creating sub-sizes or regenerating thumbnails in the future. The filename should be unique.'
-		);
-
-		// Possible clash with regenerated thumbnails in the future.
-		$this->assertSame(
-			'codeispoetry-1.jpg',
-			wp_unique_filename( $testdir, 'codeispoetry.jpg' ),
-			'The codeispoetry.png image exists. When regenerating thumbnails for it they will be converted to JPG.' .
-			'The name of the newly uploaded codeispoetry.jpg should be made unique.'
-		);
-
-		remove_filter( 'image_editor_output_format', array( $this, 'image_editor_output_format_handler' ) );
-		remove_filter( 'upload_dir', array( $this, 'upload_dir_patch_basedir' ) );
-	}
-
-	/**
-	 * Changes the output format when editing images. When uploading a PNG file
-	 * it will be converted to JPEG, GIF to JPEG, and PICT to BMP
-	 * (if the image editor in PHP supports it).
-	 *
-	 * @param array $formats
-	 *
-	 * @return array
-	 */
-	public function image_editor_output_format_handler( $formats ) {
-		$formats['image/png'] = 'image/jpeg';
-		$formats['image/gif'] = 'image/jpeg';
-		$formats['image/pct'] = 'image/bmp';
-
-		return $formats;
-	}
-
-	/**
-	 * @group add_query_arg
-	 */
-	public function test_add_query_arg() {
-		$old_req_uri = $_SERVER['REQUEST_URI'];
-
-		$urls = array(
-			'/',
-			'/2012/07/30/',
-			'edit.php',
-			admin_url( 'edit.php' ),
-			admin_url( 'edit.php', 'https' ),
-		);
-
-		$frag_urls = array(
-			'/#frag',
-			'/2012/07/30/#frag',
-			'edit.php#frag',
-			admin_url( 'edit.php#frag' ),
-			admin_url( 'edit.php#frag', 'https' ),
-		);
-
-		foreach ( $urls as $url ) {
-			$_SERVER['REQUEST_URI'] = 'nothing';
-
-			$this->assertSame( "$url?foo=1", add_query_arg( 'foo', '1', $url ) );
-			$this->assertSame( "$url?foo=1", add_query_arg( array( 'foo' => '1' ), $url ) );
-			$this->assertSame(
-				"$url?foo=2",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'foo' => '2',
-					),
-					$url
-				)
-			);
-			$this->assertSame(
-				"$url?foo=1&bar=2",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'bar' => '2',
-					),
-					$url
-				)
-			);
-
-			$_SERVER['REQUEST_URI'] = $url;
-
-			$this->assertSame( "$url?foo=1", add_query_arg( 'foo', '1' ) );
-			$this->assertSame( "$url?foo=1", add_query_arg( array( 'foo' => '1' ) ) );
-			$this->assertSame(
-				"$url?foo=2",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'foo' => '2',
-					)
-				)
-			);
-			$this->assertSame(
-				"$url?foo=1&bar=2",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'bar' => '2',
-					)
-				)
-			);
-		}
-
-		foreach ( $frag_urls as $frag_url ) {
-			$_SERVER['REQUEST_URI'] = 'nothing';
-			$url                    = str_replace( '#frag', '', $frag_url );
-
-			$this->assertSame( "$url?foo=1#frag", add_query_arg( 'foo', '1', $frag_url ) );
-			$this->assertSame( "$url?foo=1#frag", add_query_arg( array( 'foo' => '1' ), $frag_url ) );
-			$this->assertSame(
-				"$url?foo=2#frag",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'foo' => '2',
-					),
-					$frag_url
-				)
-			);
-			$this->assertSame(
-				"$url?foo=1&bar=2#frag",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'bar' => '2',
-					),
-					$frag_url
-				)
-			);
-
-			$_SERVER['REQUEST_URI'] = $frag_url;
-
-			$this->assertSame( "$url?foo=1#frag", add_query_arg( 'foo', '1' ) );
-			$this->assertSame( "$url?foo=1#frag", add_query_arg( array( 'foo' => '1' ) ) );
-			$this->assertSame(
-				"$url?foo=2#frag",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'foo' => '2',
-					)
-				)
-			);
-			$this->assertSame(
-				"$url?foo=1&bar=2#frag",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'bar' => '2',
-					)
-				)
-			);
-		}
-
-		$qs_urls = array(
-			'baz=1', // #WP4903
-			'/?baz',
-			'/2012/07/30/?baz',
-			'edit.php?baz',
-			admin_url( 'edit.php?baz' ),
-			admin_url( 'edit.php?baz', 'https' ),
-			admin_url( 'edit.php?baz&za=1' ),
-			admin_url( 'edit.php?baz=1&za=1' ),
-			admin_url( 'edit.php?baz=0&za=0' ),
-		);
-
-		foreach ( $qs_urls as $url ) {
-			$_SERVER['REQUEST_URI'] = 'nothing';
-
-			$this->assertSame( "$url&foo=1", add_query_arg( 'foo', '1', $url ) );
-			$this->assertSame( "$url&foo=1", add_query_arg( array( 'foo' => '1' ), $url ) );
-			$this->assertSame(
-				"$url&foo=2",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'foo' => '2',
-					),
-					$url
-				)
-			);
-			$this->assertSame(
-				"$url&foo=1&bar=2",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'bar' => '2',
-					),
-					$url
-				)
-			);
-
-			$_SERVER['REQUEST_URI'] = $url;
-
-			$this->assertSame( "$url&foo=1", add_query_arg( 'foo', '1' ) );
-			$this->assertSame( "$url&foo=1", add_query_arg( array( 'foo' => '1' ) ) );
-			$this->assertSame(
-				"$url&foo=2",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'foo' => '2',
-					)
-				)
-			);
-			$this->assertSame(
-				"$url&foo=1&bar=2",
-				add_query_arg(
-					array(
-						'foo' => '1',
-						'bar' => '2',
-					)
-				)
-			);
-		}
-
-		$_SERVER['REQUEST_URI'] = $old_req_uri;
-	}
-
-	/**
-	 * @ticket 31306
-	 */
-	public function test_add_query_arg_numeric_keys() {
-		$url = add_query_arg( array( 'foo' => 'bar' ), '1=1' );
-		$this->assertSame( '1=1&foo=bar', $url );
-
-		$url = add_query_arg(
-			array(
-				'foo' => 'bar',
-				'1'   => '2',
-			),
-			'1=1'
-		);
-		$this->assertSame( '1=2&foo=bar', $url );
-
-		$url = add_query_arg( array( '1' => '2' ), 'foo=bar' );
-		$this->assertSame( 'foo=bar&1=2', $url );
-	}
-
-	/**
-	 * Tests that add_query_arg removes the question mark when
-	 * a parameter is set to false.
-	 *
-	 * @dataProvider data_add_query_arg_removes_question_mark
-	 *
-	 * @ticket 44499
-	 * @group  add_query_arg
-	 *
-	 * @covers ::add_query_arg
-	 *
-	 * @param string $url      Url to test.
-	 * @param string $expected Expected URL.
-	 */
-	public function test_add_query_arg_removes_question_mark( $url, $expected, $key = 'param', $value = false ) {
-		$this->assertSame( $expected, add_query_arg( $key, $value, $url ) );
-	}
-
-	/**
-	 * Data provider.
-	 *
-	 * @return array
-	 */
-	public function data_add_query_arg_removes_question_mark() {
-		return array(
-			'anchor'                                     => array(
-				'url'      => 'http://example.org?#anchor',
-				'expected' => 'http://example.org#anchor',
-			),
-			'/ then anchor'                              => array(
-				'url'      => 'http://example.org/?#anchor',
-				'expected' => 'http://example.org/#anchor',
-			),
-			'invalid query param and anchor'             => array(
-				'url'      => 'http://example.org?param=value#anchor',
-				'expected' => 'http://example.org#anchor',
-			),
-			'/ then invalid query param and anchor'      => array(
-				'url'      => 'http://example.org/?param=value#anchor',
-				'expected' => 'http://example.org/#anchor',
-			),
-			'?#anchor when adding valid key/value args'  => array(
-				'url'      => 'http://example.org?#anchor',
-				'expected' => 'http://example.org?foo=bar#anchor',
-				'key'      => 'foo',
-				'value'    => 'bar',
-			),
-			'/?#anchor when adding valid key/value args' => array(
-				'url'      => 'http://example.org/?#anchor',
-				'expected' => 'http://example.org/?foo=bar#anchor',
-				'key'      => 'foo',
-				'value'    => 'bar',
-			),
-		);
-	}
-
-	/**
-	 * @ticket 21594
-	 */
-	public function test_get_allowed_mime_types() {
-		$mimes = get_allowed_mime_types();
-
-		$this->assertIsArray( $mimes );
-		$this->assertNotEmpty( $mimes );
-
-		add_filter( 'upload_mimes', '__return_empty_array' );
-		$mimes = get_allowed_mime_types();
-		$this->assertIsArray( $mimes );
-		$this->assertEmpty( $mimes );
-
-		remove_filter( 'upload_mimes', '__return_empty_array' );
-		$mimes = get_allowed_mime_types();
-		$this->assertIsArray( $mimes );
-		$this->assertNotEmpty( $mimes );
-	}
-
-	/**
-	 * @ticket 21594
-	 */
-	public function test_wp_get_mime_types() {
-		$mimes = wp_get_mime_types();
-
-		$this->assertIsArray( $mimes );
-		$this->assertNotEmpty( $mimes );
-
-		add_filter( 'mime_types', '__return_empty_array' );
-		$mimes = wp_get_mime_types();
-		$this->assertIsArray( $mimes );
-		$this->assertEmpty( $mimes );
-
-		remove_filter( 'mime_types', '__return_empty_array' );
-		$mimes = wp_get_mime_types();
-		$this->assertIsArray( $mimes );
-		$this->assertNotEmpty( $mimes );
-
-		// 'upload_mimes' should not affect wp_get_mime_types().
-		add_filter( 'upload_mimes', '__return_empty_array' );
-		$mimes = wp_get_mime_types();
-		$this->assertIsArray( $mimes );
-		$this->assertNotEmpty( $mimes );
-
-		remove_filter( 'upload_mimes', '__return_empty_array' );
-		$mimes2 = wp_get_mime_types();
-		$this->assertIsArray( $mimes2 );
-		$this->assertNotEmpty( $mimes2 );
-		$this->assertSame( $mimes2, $mimes );
-	}
-
-	/**
-	 * @ticket 23688
-	 */
-	public function test_canonical_charset() {
-		$orig_blog_charset = get_option( 'blog_charset' );
-
-		update_option( 'blog_charset', 'utf8' );
-		$this->assertSame( 'UTF-8', get_option( 'blog_charset' ) );
-
-		update_option( 'blog_charset', 'utf-8' );
-		$this->assertSame( 'UTF-8', get_option( 'blog_charset' ) );
-
-		update_option( 'blog_charset', 'UTF8' );
-		$this->assertSame( 'UTF-8', get_option( 'blog_charset' ) );
-
-		update_option( 'blog_charset', 'UTF-8' );
-		$this->assertSame( 'UTF-8', get_option( 'blog_charset' ) );
-
-		update_option( 'blog_charset', 'ISO-8859-1' );
-		$this->assertSame( 'ISO-8859-1', get_option( 'blog_charset' ) );
-
-		update_option( 'blog_charset', 'ISO8859-1' );
-		$this->assertSame( 'ISO-8859-1', get_option( 'blog_charset' ) );
-
-		update_option( 'blog_charset', 'iso8859-1' );
-		$this->assertSame( 'ISO-8859-1', get_option( 'blog_charset' ) );
-
-		update_option( 'blog_charset', 'iso-8859-1' );
-		$this->assertSame( 'ISO-8859-1', get_option( 'blog_charset' ) );
-
-		// Arbitrary strings are passed through.
-		update_option( 'blog_charset', 'foobarbaz' );
-		$this->assertSame( 'foobarbaz', get_option( 'blog_charset' ) );
-
-		update_option( 'blog_charset', $orig_blog_charset );
-	}
-
-	/**
-	 * @dataProvider data_device_can_upload
-	 */
-	public function test_device_can_upload( $user_agent, $expected ) {
-		$_SERVER['HTTP_USER_AGENT'] = $user_agent;
-		$actual                     = _device_can_upload();
-		unset( $_SERVER['HTTP_USER_AGENT'] );
-		$this->assertSame( $expected, $actual );
-	}
-
-	public function data_device_can_upload() {
-		return array(
-			// iPhone iOS 5.0.1, Safari 5.1.
-			array(
-				'Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Mobile/9A406)',
-				false,
-			),
-			// iPad iOS 3.2, Safari 4.0.4.
-			array(
-				'Mozilla/5.0 (iPad; U; CPU OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B334b Safari/531.21.10',
-				false,
-			),
-			// iPod iOS 4.3.3, Safari 5.0.2.
-			array(
-				'Mozilla/5.0 (iPod; U; CPU iPhone OS 4_3_3 like Mac OS X; ja-jp) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5',
-				false,
-			),
-			// iPhone iOS 6.0.0, Safari 6.0.
-			array(
-				'Mozilla/5.0 (iPhone; CPU iPhone OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25',
-				true,
-			),
-			// iPad iOS 6.0.0, Safari 6.0.
-			array(
-				'Mozilla/5.0 (iPad; CPU OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25',
-				true,
-			),
-			// Android 2.2, Android Webkit Browser.
-			array(
-				'Mozilla/5.0 (Android 2.2; Windows; U; Windows NT 6.1; en-US) AppleWebKit/533.19.4 (KHTML, like Gecko) Version/5.0.3 Safari/533.19.4',
-				true,
-			),
-			// BlackBerry 9900, BlackBerry browser.
-			array(
-				'Mozilla/5.0 (BlackBerry; U; BlackBerry 9900; en) AppleWebKit/534.11+ (KHTML, like Gecko) Version/7.1.0.346 Mobile Safari/534.11+',
-				true,
-			),
-			// Windows Phone 8.0, Internet Explorer 10.0.
-			array(
-				'Mozilla/5.0 (compatible; MSIE 10.0; Windows Phone 8.0; Trident/6.0; IEMobile/10.0; ARM; Touch; NOKIA; Lumia 920)',
-				true,
-			),
-			// Ubuntu desktop, Firefox 41.0.
-			array(
-				'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:41.0) Gecko/20100101 Firefox/41.0',
-				true,
-			),
-		);
-	}
-
-	/**
-	 * @ticket 9064
-	 */
-	public function test_wp_extract_urls() {
-		$original_urls = array(
-			'http://woo.com/1,2,3,4,5,6/-1-2-3-4-/woo.html',
-			'http://this.com',
-			'http://127.0.0.1',
-			'http://www111.urwyeoweytwutreyytqytwetowteuiiu.com/?346236346326&2134362574863.437',
-			'http://wordpress-core/1,2,3,4,5,6/-1-2-3-4-/woo.html',
-			'http://wordpress-core.com:8080/',
-			'http://www.website.com:5000',
-			'http://wordpress-core/?346236346326&2134362574863.437',
-			'http://افغانستا.icom.museum',
-			'http://الجزائر.icom.museum',
-			'http://österreich.icom.museum',
-			'http://বাংলাদেশ.icom.museum',
-			'http://беларусь.icom.museum',
-			'http://belgië.icom.museum',
-			'http://българия.icom.museum',
-			'http://تشادر.icom.museum',
-			'http://中国.icom.museum',
-			// 'http://القمر.icom.museum',         // Comoros http://القمر.icom.museum
-			// 'http://κυπρος.icom.museum',        // Cyprus  http://κυπρος.icom.museum
-			'http://českárepublika.icom.museum',
-			// 'http://مصر.icom.museum',           // Egypt   http://مصر.icom.museum
-			'http://ελλάδα.icom.museum',
-			'http://magyarország.icom.museum',
-			'http://ísland.icom.museum',
-			'http://भारत.icom.museum',
-			'http://ايران.icom.museum',
-			'http://éire.icom.museum',
-			'http://איקו״ם.ישראל.museum',
-			'http://日本.icom.museum',
-			'http://الأردن.icom.museum',
-			'http://қазақстан.icom.museum',
-			'http://한국.icom.museum',
-			'http://кыргызстан.icom.museum',
-			'http://ລາວ.icom.museum',
-			'http://لبنان.icom.museum',
-			'http://македонија.icom.museum',
-			// 'http://موريتانيا.icom.museum',     // Mauritania http://موريتانيا.icom.museum
-			'http://méxico.icom.museum',
-			'http://монголулс.icom.museum',
-			// 'http://المغرب.icom.museum',        // Morocco    http://المغرب.icom.museum
-			'http://नेपाल.icom.museum',
-			// 'http://عمان.icom.museum',          // Oman       http://عمان.icom.museum
-			'http://قطر.icom.museum',
-			'http://românia.icom.museum',
-			'http://россия.иком.museum',
-			'http://србијаицрнагора.иком.museum',
-			'http://இலங்கை.icom.museum',
-			'http://españa.icom.museum',
-			'http://ไทย.icom.museum',
-			'http://تونس.icom.museum',
-			'http://türkiye.icom.museum',
-			'http://украина.icom.museum',
-			'http://việtnam.icom.museum',
-			'ftp://127.0.0.1/',
-			'http://www.woo.com/video?v=exvUH2qKLTU',
-			'http://taco.com?burrito=enchilada#guac',
-			'http://example.org/?post_type=post&p=4',
-			'http://example.org/?post_type=post&p=5',
-			'http://example.org/?post_type=post&p=6',
-			'http://typo-in-query.org/?foo=bar&ampbaz=missing_semicolon',
-		);
-
-		$blob = '
-			http://woo.com/1,2,3,4,5,6/-1-2-3-4-/woo.html
-
-			http://this.com
-
-			http://127.0.0.1
-
-			http://www111.urwyeoweytwutreyytqytwetowteuiiu.com/?346236346326&amp;2134362574863.437
-
-			http://wordpress-core/1,2,3,4,5,6/-1-2-3-4-/woo.html
-
-			http://wordpress-core.com:8080/
-
-			http://www.website.com:5000
-
-			http://wordpress-core/?346236346326&amp;2134362574863.437
-
-			http://افغانستا.icom.museum
-			http://الجزائر.icom.museum
-			http://österreich.icom.museum
-			http://বাংলাদেশ.icom.museum
-			http://беларусь.icom.museum
-			http://belgië.icom.museum
-			http://българия.icom.museum
-			http://تشادر.icom.museum
-			http://中国.icom.museum
-			http://českárepublika.icom.museum
-			http://ελλάδα.icom.museum
-			http://magyarország.icom.museum
-			http://ísland.icom.museum
-			http://भारत.icom.museum
-			http://ايران.icom.museum
-			http://éire.icom.museum
-			http://איקו״ם.ישראל.museum
-			http://日本.icom.museum
-			http://الأردن.icom.museum
-			http://қазақстан.icom.museum
-			http://한국.icom.museum
-			http://кыргызстан.icom.museum
-			http://ລາວ.icom.museum
-			http://لبنان.icom.museum
-			http://македонија.icom.museum
-			http://méxico.icom.museum
-			http://монголулс.icom.museum
-			http://नेपाल.icom.museum
-			http://قطر.icom.museum
-			http://românia.icom.museum
-			http://россия.иком.museum
-			http://србијаицрнагора.иком.museum
-			http://இலங்கை.icom.museum
-			http://españa.icom.museum
-			http://ไทย.icom.museum
-			http://تونس.icom.museum
-			http://türkiye.icom.museum
-			http://украина.icom.museum
-			http://việtnam.icom.museum
-			ftp://127.0.0.1/
-			http://www.woo.com/video?v=exvUH2qKLTU
-
-			http://taco.com?burrito=enchilada#guac
-
-			http://example.org/?post_type=post&amp;p=4
-			http://example.org/?post_type=post&#038;p=5
-			http://example.org/?post_type=post&p=6
-
-			http://typo-in-query.org/?foo=bar&ampbaz=missing_semicolon
-		';
-
-		$urls = wp_extract_urls( $blob );
-		$this->assertNotEmpty( $urls );
-		$this->assertIsArray( $urls );
-		$this->assertCount( count( $original_urls ), $urls );
-		$this->assertSame( $original_urls, $urls );
-
-		$exploded = array_values( array_filter( array_map( 'trim', explode( "\n", $blob ) ) ) );
-		// wp_extract_urls() calls html_entity_decode().
-		$decoded = array_map( 'html_entity_decode', $exploded );
-
-		$this->assertSame( $decoded, $urls );
-		$this->assertSame( $original_urls, $decoded );
-
-		$blob = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor
-			incididunt ut labore http://woo.com/1,2,3,4,5,6/-1-2-3-4-/woo.html et dolore magna aliqua.
-			Ut http://this.com enim ad minim veniam, quis nostrud exercitation 16.06. to 18.06.2014 ullamco http://127.0.0.1
-			laboris nisi ut aliquip ex http://www111.urwyeoweytwutreyytqytwetowteuiiu.com/?346236346326&amp;2134362574863.437 ea
-			commodo consequat. http://wordpress-core/1,2,3,4,5,6/-1-2-3-4-/woo.html Duis aute irure dolor in reprehenderit in voluptate
-			velit esse http://wordpress-core.com:8080/ cillum dolore eu fugiat nulla <A href="http://www.website.com:5000">http://www.website.com:5000</B> pariatur. Excepteur sint occaecat cupidatat non proident,
-			sunt in culpa qui officia deserunt mollit http://wordpress-core/?346236346326&amp;2134362574863.437 anim id est laborum.';
-
-		$urls = wp_extract_urls( $blob );
-		$this->assertNotEmpty( $urls );
-		$this->assertIsArray( $urls );
-		$this->assertCount( 8, $urls );
-		$this->assertSame( array_slice( $original_urls, 0, 8 ), $urls );
-
-		$blob = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor
-			incididunt ut labore <a href="http://woo.com/1,2,3,4,5,6/-1-2-3-4-/woo.html">343462^</a> et dolore magna aliqua.
-			Ut <a href="http://this.com">&amp;3640i6p1yi499</a> enim ad minim veniam, quis nostrud exercitation 16.06. to 18.06.2014 ullamco <a href="http://127.0.0.1">localhost</a>
-			laboris nisi ut aliquip ex <a href="http://www111.urwyeoweytwutreyytqytwetowteuiiu.com/?346236346326&amp;2134362574863.437">343462^</a> ea
-			commodo consequat. <a href="http://wordpress-core/1,2,3,4,5,6/-1-2-3-4-/woo.html">343462^</a> Duis aute irure dolor in reprehenderit in voluptate
-			velit esse <a href="http://wordpress-core.com:8080/">-3-4--321-64-4@#!$^$!@^@^</a> cillum dolore eu <A href="http://www.website.com:5000">http://www.website.com:5000</B> fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident,
-			sunt in culpa qui officia deserunt mollit <a href="http://wordpress-core/?346236346326&amp;2134362574863.437">)(*&^%$</a> anim id est laborum.';
-
-		$urls = wp_extract_urls( $blob );
-		$this->assertNotEmpty( $urls );
-		$this->assertIsArray( $urls );
-		$this->assertCount( 8, $urls );
-		$this->assertSame( array_slice( $original_urls, 0, 8 ), $urls );
-	}
-
-	/**
-	 * Tests for backward compatibility of `wp_extract_urls` to remove unused semicolons.
-	 *
-	 * @ticket 30580
-	 *
-	 * @covers ::wp_extract_urls
-	 */
-	public function test_wp_extract_urls_remove_semicolon() {
-		$expected = array(
-			'http://typo.com',
-			'http://example.org/?post_type=post&p=8',
-		);
-		$actual   = wp_extract_urls(
-			'
-				http://typo.com;
-				http://example.org/?post_type=;p;o;s;t;&amp;p=8;
-			'
-		);
-
-		$this->assertSame( $expected, $actual );
-	}
-
-	/**
-	 * @ticket 28786
-	 */
-	public function test_wp_json_encode() {
-		$this->assertSame( wp_json_encode( 'a' ), '"a"' );
-	}
-
-	/**
-	 * @ticket 28786
-	 */
-	public function test_wp_json_encode_utf8() {
-		$this->assertSame( wp_json_encode( '这' ), '"\u8fd9"' );
-	}
-
-	/**
-	 * @ticket 28786
-	 * @requires function mb_detect_order
-	 */
-	public function test_wp_json_encode_non_utf8() {
-		$charsets     = mb_detect_order();
-		$old_charsets = $charsets;
-		if ( ! in_array( 'EUC-JP', $charsets, true ) ) {
-			$charsets[] = 'EUC-JP';
-			mb_detect_order( $charsets );
-		}
-
-		$eucjp = mb_convert_encoding( 'aあb', 'EUC-JP', 'UTF-8' );
-		$utf8  = mb_convert_encoding( $eucjp, 'UTF-8', 'EUC-JP' );
-
-		$this->assertSame( 'aあb', $utf8 );
-
-		$this->assertSame( '"a\u3042b"', wp_json_encode( $eucjp ) );
-
-		mb_detect_order( $old_charsets );
-	}
-
-	/**
-	 * @ticket 28786
-	 * @requires function mb_detect_order
-	 */
-	public function test_wp_json_encode_non_utf8_in_array() {
-		$charsets     = mb_detect_order();
-		$old_charsets = $charsets;
-		if ( ! in_array( 'EUC-JP', $charsets, true ) ) {
-			$charsets[] = 'EUC-JP';
-			mb_detect_order( $charsets );
-		}
-
-		$eucjp = mb_convert_encoding( 'aあb', 'EUC-JP', 'UTF-8' );
-		$utf8  = mb_convert_encoding( $eucjp, 'UTF-8', 'EUC-JP' );
-
-		$this->assertSame( 'aあb', $utf8 );
-
-		$this->assertSame( '["c","a\u3042b"]', wp_json_encode( array( 'c', $eucjp ) ) );
-
-		mb_detect_order( $old_charsets );
-	}
-
-	/**
-	 * @ticket 28786
-	 */
-	public function test_wp_json_encode_array() {
-		$this->assertSame( wp_json_encode( array( 'a' ) ), '["a"]' );
-	}
-
-	/**
-	 * @ticket 28786
-	 */
-	public function test_wp_json_encode_object() {
-		$object    = new stdClass();
-		$object->a = 'b';
-		$this->assertSame( wp_json_encode( $object ), '{"a":"b"}' );
-	}
-
-	/**
-	 * @ticket 28786
-	 */
-	public function test_wp_json_encode_depth() {
-		$data = array( array( array( 1, 2, 3 ) ) );
-		$json = wp_json_encode( $data, 0, 1 );
-		$this->assertFalse( $json );
-
-		$data = array( 'あ', array( array( 1, 2, 3 ) ) );
-		$json = wp_json_encode( $data, 0, 1 );
-		$this->assertFalse( $json );
-	}
-
-	/**
-	 * @ticket 53238
-	 */
-	public function test_wp_json_file_decode() {
-		$result = wp_json_file_decode(
-			DIR_TESTDATA . '/blocks/notice/block.json'
-		);
-
-		$this->assertIsObject( $result );
-		$this->assertSame( 'tests/notice', $result->name );
-	}
-
-	/**
-	 * @ticket 53238
-	 */
-	public function test_wp_json_file_decode_associative_array() {
-		$result = wp_json_file_decode(
-			DIR_TESTDATA . '/blocks/notice/block.json',
-			array( 'associative' => true )
-		);
-
-		$this->assertIsArray( $result );
-		$this->assertSame( 'tests/notice', $result['name'] );
-	}
-
-	/**
-	 * @ticket 36054
-	 * @dataProvider data_mysql_to_rfc3339
-	 */
-	public function test_mysql_to_rfc3339( $expected, $actual ) {
-		$date_return = mysql_to_rfc3339( $actual );
-
-		$this->assertIsString( $date_return, 'The date return must be a string' );
-		$this->assertNotEmpty( $date_return, 'The date return could not be an empty string' );
-		$this->assertSame( $expected, $date_return, 'The date does not match' );
-		$this->assertEquals( new DateTime( $expected ), new DateTime( $date_return ), 'The date is not the same after the call method' );
-	}
-
-	public function data_mysql_to_rfc3339() {
-		return array(
-			array( '2016-03-15T18:54:46', '15-03-2016 18:54:46' ),
-			array( '2016-03-02T19:13:25', '2016-03-02 19:13:25' ),
-			array( '2016-03-02T19:13:00', '2016-03-02 19:13' ),
-			array( '2016-03-02T19:13:00', '16-03-02 19:13' ),
-			array( '2016-03-02T19:13:00', '16-03-02 19:13' ),
-		);
-	}
-
-	/**
-	 * @ticket 35987
-	 */
-	public function test_wp_get_ext_types() {
-		$extensions = wp_get_ext_types();
-
-		$this->assertIsArray( $extensions );
-		$this->assertNotEmpty( $extensions );
-
-		add_filter( 'ext2type', '__return_empty_array' );
-		$extensions = wp_get_ext_types();
-		$this->assertSame( array(), $extensions );
-
-		remove_filter( 'ext2type', '__return_empty_array' );
-		$extensions = wp_get_ext_types();
-		$this->assertIsArray( $extensions );
-		$this->assertNotEmpty( $extensions );
-	}
-
-	/**
-	 * @ticket 35987
-	 */
-	public function test_wp_ext2type() {
-		$extensions = wp_get_ext_types();
-
-		$this->assertNotEmpty( $extensions );
-
-		foreach ( $extensions as $type => $extension_list ) {
-			foreach ( $extension_list as $extension ) {
-				$this->assertSame( $type, wp_ext2type( $extension ) );
-				$this->assertSame( $type, wp_ext2type( strtoupper( $extension ) ) );
-			}
-		}
-
-		$this->assertNull( wp_ext2type( 'unknown_format' ) );
-	}
-
-	/**
-	 * Tests raising the memory limit.
-	 *
-	 * Unfortunately as the default for 'WP_MAX_MEMORY_LIMIT' in the
-	 * test suite is -1, we can not test the memory limit negotiations.
-	 *
-	 * @ticket 32075
-	 */
-	public function test_wp_raise_memory_limit() {
-		if ( -1 !== WP_MAX_MEMORY_LIMIT ) {
-			$this->markTestSkipped( 'WP_MAX_MEMORY_LIMIT should be set to -1.' );
-		}
-
-		$ini_limit_before = ini_get( 'memory_limit' );
-		$raised_limit     = wp_raise_memory_limit();
-		$ini_limit_after  = ini_get( 'memory_limit' );
-
-		$this->assertSame( $ini_limit_before, $ini_limit_after );
-		$this->assertFalse( $raised_limit );
-		$this->assertEquals( WP_MAX_MEMORY_LIMIT, $ini_limit_after );
-	}
-
-	/**
-	 * Tests wp_generate_uuid4().
-	 *
-	 * @covers ::wp_generate_uuid4
-	 * @ticket 38164
-	 */
-	public function test_wp_generate_uuid4() {
-		$uuids = array();
-		for ( $i = 0; $i < 20; $i += 1 ) {
-			$uuid = wp_generate_uuid4();
-			$this->assertTrue( wp_is_uuid( $uuid, 4 ) );
-			$uuids[] = $uuid;
-		}
-
-		$unique_uuids = array_unique( $uuids );
-		$this->assertSame( $uuids, $unique_uuids );
-	}
-
-	/**
-	 * Tests wp_is_uuid().
-	 *
-	 * @covers ::wp_is_uuid
-	 * @ticket 39778
-	 */
-	public function test_wp_is_valid_uuid() {
-		$uuids_v4 = array(
-			'27fe2421-780c-44c5-b39b-fff753092b55',
-			'b7c7713a-4ee9-45a1-87ed-944a90390fc7',
-			'fbedbe35-7bf5-49cc-a5ac-0343bd94360a',
-			'4c58e67e-123b-4290-a41c-5eeb6970fa3e',
-			'f54f5b78-e414-4637-84a9-a6cdc94a1beb',
-			'd1c533ac-abcf-44b6-9b0e-6477d2c91b09',
-			'7fcd683f-e5fd-454a-a8b9-ed15068830da',
-			'7962c750-e58c-470a-af0d-ec1eae453ff2',
-			'a59878ce-9a67-4493-8ca0-a756b52804b3',
-			'6faa519d-1e13-4415-bd6f-905ae3689d1d',
-		);
-
-		foreach ( $uuids_v4 as $uuid ) {
-			$this->assertTrue( wp_is_uuid( $uuid, 4 ) );
-		}
-
-		$uuids = array(
-			'00000000-0000-0000-0000-000000000000', // Nil.
-			'9e3a0460-d72d-11e4-a631-c8e0eb141dab', // Version 1.
-			'2c1d43b8-e6d7-376e-af7f-d4bde997cc3f', // Version 3.
-			'39888f87-fb62-5988-a425-b2ea63f5b81e', // Version 5.
-		);
-
-		foreach ( $uuids as $uuid ) {
-			$this->assertTrue( wp_is_uuid( $uuid ) );
-			$this->assertFalse( wp_is_uuid( $uuid, 4 ) );
-		}
-
-		$invalid_uuids = array(
-			'a19d5192-ea41-41e6-b006',
-			'this-is-not-valid',
-			1234,
-			true,
-			array(),
-		);
-
-		foreach ( $invalid_uuids as $invalid_uuid ) {
-			$this->assertFalse( wp_is_uuid( $invalid_uuid, 4 ) );
-			$this->assertFalse( wp_is_uuid( $invalid_uuid ) );
-		}
-	}
-
-	/**
-	 * Tests wp_unique_id().
-	 *
-	 * @covers ::wp_unique_id
-	 * @ticket 44883
-	 */
-	public function test_wp_unique_id() {
-
-		// Test without prefix.
-		$ids = array();
-		for ( $i = 0; $i < 20; $i += 1 ) {
-			$id = wp_unique_id();
-			$this->assertIsString( $id );
-			$this->assertIsNumeric( $id );
-			$ids[] = $id;
-		}
-		$this->assertSame( $ids, array_unique( $ids ) );
-
-		// Test with prefix.
-		$ids = array();
-		for ( $i = 0; $i < 20; $i += 1 ) {
-			$id = wp_unique_id( 'foo-' );
-			$this->assertMatchesRegularExpression( '/^foo-\d+$/', $id );
-			$ids[] = $id;
-		}
-		$this->assertSame( $ids, array_unique( $ids ) );
-	}
-
-	/**
-	 * @ticket 40017
-	 * @dataProvider data_wp_get_image_mime
-	 */
-	public function test_wp_get_image_mime( $file, $expected ) {
-		if ( ! is_callable( 'exif_imagetype' ) && ! function_exists( 'getimagesize' ) ) {
-			$this->markTestSkipped( 'The exif PHP extension is not loaded.' );
-		}
-
-		if ( is_array( $expected ) ) {
-			$this->assertContains( wp_get_image_mime( $file ), $expected );
-		} else {
-			$this->assertSame( $expected, wp_get_image_mime( $file ) );
-		}
-	}
-
-	/**
-	 * Data provider for test_wp_get_image_mime().
-	 */
-	public function data_wp_get_image_mime() {
-		$data = array(
-			// Standard JPEG.
-			array(
-				DIR_TESTDATA . '/images/test-image.jpg',
-				'image/jpeg',
-			),
-			// Standard GIF.
-			array(
-				DIR_TESTDATA . '/images/test-image.gif',
-				'image/gif',
-			),
-			// Standard PNG.
-			array(
-				DIR_TESTDATA . '/images/test-image.png',
-				'image/png',
-			),
-			// Image with wrong extension.
-			array(
-				DIR_TESTDATA . '/images/test-image-mime-jpg.png',
-				'image/jpeg',
-			),
-			// Animated WebP.
-			array(
-				DIR_TESTDATA . '/images/webp-animated.webp',
-				'image/webp',
-			),
-			// Lossless WebP.
-			array(
-				DIR_TESTDATA . '/images/webp-lossless.webp',
-				'image/webp',
-			),
-			// Lossy WebP.
-			array(
-				DIR_TESTDATA . '/images/webp-lossy.webp',
-				'image/webp',
-			),
-			// Transparent WebP.
-			array(
-				DIR_TESTDATA . '/images/webp-transparent.webp',
-				'image/webp',
-			),
-			// Not an image.
-			array(
-				DIR_TESTDATA . '/uploads/dashicons.woff',
-				false,
-			),
-			// Animated AVIF.
-			array(
-				DIR_TESTDATA . '/images/avif-animated.avif',
-				'image/avif',
-			),
-			// Lossless AVIF.
-			array(
-				DIR_TESTDATA . '/images/avif-lossless.avif',
-				'image/avif',
-			),
-			// Lossy AVIF.
-			array(
-				DIR_TESTDATA . '/images/avif-lossy.avif',
-				'image/avif',
-			),
-			// Transparent AVIF.
-			array(
-				DIR_TESTDATA . '/images/avif-transparent.avif',
-				'image/avif',
-			),
-			// HEIC.
-			array(
-				DIR_TESTDATA . '/images/test-image.heic',
-				// In PHP 8.5, it returns 'image/heif'. Before that, it returns 'image/heic'.
-				array( 'image/heic', 'image/heif' ),
-			),
-		);
-
-		return $data;
-	}
-
-	/**
-	 * @ticket 35725
-	 * @dataProvider data_wp_getimagesize
-	 */
-	public function test_wp_getimagesize( $file, $expected ) {
-		if ( ! is_callable( 'exif_imagetype' ) && ! function_exists( 'getimagesize' ) ) {
-			$this->markTestSkipped( 'The exif PHP extension is not loaded.' );
-		}
-
-		$result = wp_getimagesize( $file );
-
-		// The getimagesize() function varies in its response, so
-		// let's restrict comparison to expected keys only.
-		if ( is_array( $expected ) ) {
-			foreach ( $expected as $k => $v ) {
-				$this->assertArrayHasKey( $k, $result );
-				$this->assertSame( $expected[ $k ], $result[ $k ] );
-			}
-		} else {
-			$this->assertSame( $expected, $result );
-		}
-	}
-
-	/**
-	 * Data provider for test_wp_getimagesize().
-	 */
-	public function data_wp_getimagesize() {
-		$data = array(
-			// Standard JPEG.
-			array(
-				DIR_TESTDATA . '/images/test-image.jpg',
-				array(
-					50,
-					50,
-					IMAGETYPE_JPEG,
-					'width="50" height="50"',
-					'mime' => 'image/jpeg',
-				),
-			),
-			// Standard GIF.
-			array(
-				DIR_TESTDATA . '/images/test-image.gif',
-				array(
-					50,
-					50,
-					IMAGETYPE_GIF,
-					'width="50" height="50"',
-					'mime' => 'image/gif',
-				),
-			),
-			// Standard PNG.
-			array(
-				DIR_TESTDATA . '/images/test-image.png',
-				array(
-					50,
-					50,
-					IMAGETYPE_PNG,
-					'width="50" height="50"',
-					'mime' => 'image/png',
-				),
-			),
-			// Image with wrong extension.
-			array(
-				DIR_TESTDATA . '/images/test-image-mime-jpg.png',
-				array(
-					50,
-					50,
-					IMAGETYPE_JPEG,
-					'width="50" height="50"',
-					'mime' => 'image/jpeg',
-				),
-			),
-			// Animated WebP.
-			array(
-				DIR_TESTDATA . '/images/webp-animated.webp',
-				array(
-					100,
-					100,
-					IMAGETYPE_WEBP,
-					'width="100" height="100"',
-					'mime' => 'image/webp',
-				),
-			),
-			// Lossless WebP.
-			array(
-				DIR_TESTDATA . '/images/webp-lossless.webp',
-				array(
-					1200,
-					675,
-					IMAGETYPE_WEBP,
-					'width="1200" height="675"',
-					'mime' => 'image/webp',
-				),
-			),
-			// Lossy WebP.
-			array(
-				DIR_TESTDATA . '/images/webp-lossy.webp',
-				array(
-					1200,
-					675,
-					IMAGETYPE_WEBP,
-					'width="1200" height="675"',
-					'mime' => 'image/webp',
-				),
-			),
-			// Transparent WebP.
-			array(
-				DIR_TESTDATA . '/images/webp-transparent.webp',
-				array(
-					1200,
-					675,
-					IMAGETYPE_WEBP,
-					'width="1200" height="675"',
-					'mime' => 'image/webp',
-				),
-			),
-			// Not an image.
-			array(
-				DIR_TESTDATA . '/uploads/dashicons.woff',
-				false,
-			),
-			// Animated AVIF.
-			array(
-				DIR_TESTDATA . '/images/avif-animated.avif',
-				array(
-					150,
-					150,
-					IMAGETYPE_AVIF,
-					'width="150" height="150"',
-					'mime' => 'image/avif',
-				),
-			),
-			// Lossless AVIF.
-			array(
-				DIR_TESTDATA . '/images/avif-lossless.avif',
-				array(
-					400,
-					400,
-					IMAGETYPE_AVIF,
-					'width="400" height="400"',
-					'mime' => 'image/avif',
-				),
-			),
-			// Lossy AVIF.
-			array(
-				DIR_TESTDATA . '/images/avif-lossy.avif',
-				array(
-					400,
-					400,
-					IMAGETYPE_AVIF,
-					'width="400" height="400"',
-					'mime' => 'image/avif',
-				),
-			),
-			// Transparent AVIF.
-			array(
-				DIR_TESTDATA . '/images/avif-transparent.avif',
-				array(
-					128,
-					128,
-					IMAGETYPE_AVIF,
-					'width="128" height="128"',
-					'mime' => 'image/avif',
-				),
-			),
-			// Grid AVIF.
-			array(
-				DIR_TESTDATA . '/images/avif-alpha-grid2x1.avif',
-				array(
-					199,
-					200,
-					IMAGETYPE_AVIF,
-					'width="199" height="200"',
-					'mime' => 'image/avif',
-				),
-			),
-		);
-
-		return $data;
-	}
-
-	/**
-	 * Tests that wp_getimagesize() correctly handles HEIC image files.
-	 *
-	 * @ticket 53645
-	 */
-	public function test_wp_getimagesize_heic() {
-		if ( ! is_callable( 'exif_imagetype' ) && ! function_exists( 'getimagesize' ) ) {
-			$this->markTestSkipped( 'The exif PHP extension is not loaded.' );
-		}
-
-		$file = DIR_TESTDATA . '/images/test-image.heic';
-
-		$editor = wp_get_image_editor( $file );
-		if ( is_wp_error( $editor ) || ! $editor->supports_mime_type( 'image/heic' ) ) {
-			$this->markTestSkipped( 'No HEIC support in the editor engine on this system.' );
-		}
-
-		$expected = array(
-			1180,
-			1180,
-			IMAGETYPE_HEIF,
-			'width="1180" height="1180"',
-		);
-
-		// As of PHP 8.5.0, getimagesize() supports HEIF/HEIC files.
-		if ( PHP_VERSION_ID >= 80500 ) {
-			$expected = array_merge(
-				$expected,
-				array(
-					'bits'        => 8,
-					'channels'    => 3,
-					'mime'        => 'image/heif',
-					'width_unit'  => 'px',
-					'height_unit' => 'px',
-				)
-			);
-		} else {
-			$expected['mime'] = 'image/heic';
-		}
-
-		$result = wp_getimagesize( $file );
-		$this->assertSame( $expected, $result );
-	}
-
-
-	/**
-	 * @ticket 39550
-	 * @dataProvider data_wp_check_filetype_and_ext
-	 * @requires extension fileinfo
-	 */
-	public function test_wp_check_filetype_and_ext( $file, $filename, $expected ) {
-		$this->assertSame( $expected, wp_check_filetype_and_ext( $file, $filename ) );
-	}
-
-	public function data_wp_check_filetype_and_ext() {
-		$data = array(
-			// Standard image.
-			array(
-				DIR_TESTDATA . '/images/canola.jpg',
-				'canola.jpg',
-				array(
-					'ext'             => 'jpg',
-					'type'            => 'image/jpeg',
-					'proper_filename' => false,
-				),
-			),
-			// Image with wrong extension.
-			array(
-				DIR_TESTDATA . '/images/test-image-mime-jpg.png',
-				'test-image-mime-jpg.png',
-				array(
-					'ext'             => 'jpg',
-					'type'            => 'image/jpeg',
-					'proper_filename' => 'test-image-mime-jpg.jpg',
-				),
-			),
-			// Image without extension.
-			array(
-				DIR_TESTDATA . '/images/test-image-no-extension',
-				'test-image-no-extension',
-				array(
-					'ext'             => false,
-					'type'            => false,
-					'proper_filename' => false,
-				),
-			),
-			// Valid non-image file with an image extension.
-			array(
-				DIR_TESTDATA . '/formatting/big5.txt',
-				'big5.jpg',
-				array(
-					'ext'             => false,
-					'type'            => false,
-					'proper_filename' => false,
-				),
-			),
-			// Non-image file not allowed.
-			array(
-				DIR_TESTDATA . '/export/crazy-cdata.xml',
-				'crazy-cdata.xml',
-				array(
-					'ext'             => false,
-					'type'            => false,
-					'proper_filename' => false,
-				),
-			),
-			// Non-image file not allowed even if it's named like one.
-			array(
-				DIR_TESTDATA . '/export/crazy-cdata.xml',
-				'crazy-cdata.jpg',
-				array(
-					'ext'             => false,
-					'type'            => false,
-					'proper_filename' => false,
-				),
-			),
-			// Non-image file not allowed if it's named like something else.
-			array(
-				DIR_TESTDATA . '/export/crazy-cdata.xml',
-				'crazy-cdata.doc',
-				array(
-					'ext'             => false,
-					'type'            => false,
-					'proper_filename' => false,
-				),
-			),
-			// Non-image file not allowed even if it's named like one.
-			array(
-				DIR_TESTDATA . '/export/crazy-cdata.xml',
-				'crazy-cdata.jpg',
-				array(
-					'ext'             => false,
-					'type'            => false,
-					'proper_filename' => false,
-				),
-			),
-			// Non-image file not allowed if it's named like something else.
-			array(
-				DIR_TESTDATA . '/export/crazy-cdata.xml',
-				'crazy-cdata.doc',
-				array(
-					'ext'             => false,
-					'type'            => false,
-					'proper_filename' => false,
-				),
-			),
-		);
-
-		// Test a few additional file types on single sites.
-		if ( ! is_multisite() ) {
-			$data = array_merge(
-				$data,
-				array(
-					// Standard non-image file.
-					array(
-						DIR_TESTDATA . '/formatting/big5.txt',
-						'big5.txt',
-						array(
-							'ext'             => 'txt',
-							'type'            => 'text/plain',
-							'proper_filename' => false,
-						),
-					),
-					// Google Docs file for which finfo_file() returns a duplicate mime type.
-					array(
-						DIR_TESTDATA . '/uploads/double-mime-type.docx',
-						'double-mime-type.docx',
-						array(
-							'ext'             => 'docx',
-							'type'            => 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
-							'proper_filename' => false,
-						),
-					),
-					// Non-image file with wrong sub-type.
-					array(
-						DIR_TESTDATA . '/uploads/pages-to-word.docx',
-						'pages-to-word.docx',
-						array(
-							'ext'             => 'docx',
-							'type'            => 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
-							'proper_filename' => false,
-						),
-					),
-					// FLAC file.
-					array(
-						DIR_TESTDATA . '/uploads/small-audio.flac',
-						'small-audio.flac',
-						array(
-							'ext'             => 'flac',
-							'type'            => 'audio/flac',
-							'proper_filename' => false,
-						),
-					),
-					// Assorted text/* sample files
-					array(
-						DIR_TESTDATA . '/uploads/test.vtt',
-						'test.vtt',
-						array(
-							'ext'             => 'vtt',
-							'type'            => 'text/vtt',
-							'proper_filename' => false,
-						),
-					),
-					array(
-						DIR_TESTDATA . '/uploads/test.csv',
-						'test.csv',
-						array(
-							'ext'             => 'csv',
-							'type'            => 'text/csv',
-							'proper_filename' => false,
-						),
-					),
-					// RTF files.
-					array(
-						DIR_TESTDATA . '/uploads/test.rtf',
-						'test.rtf',
-						array(
-							'ext'             => 'rtf',
-							'type'            => 'application/rtf',
-							'proper_filename' => false,
-						),
-					),
-				)
-			);
-		}
-
-		return $data;
-	}
-
-	/**
-	 * @ticket 39550
-	 * @group ms-excluded
-	 * @requires extension fileinfo
-	 */
-	public function test_wp_check_filetype_and_ext_with_filtered_svg() {
-		$file     = DIR_TESTDATA . '/uploads/video-play.svg';
-		$filename = 'video-play.svg';
-
-		$expected = array(
-			'ext'             => 'svg',
-			'type'            => 'image/svg+xml',
-			'proper_filename' => false,
-		);
-
-		add_filter(
-			'upload_mimes',
-			static function ( $mimes ) {
-				$mimes['svg'] = 'image/svg+xml';
-				return $mimes;
-			}
-		);
-
-		$this->assertSame( $expected, wp_check_filetype_and_ext( $file, $filename ) );
-	}
-
-	/**
-	 * @ticket 39550
-	 * @group ms-excluded
-	 * @requires extension fileinfo
-	 */
-	public function test_wp_check_filetype_and_ext_with_filtered_woff() {
-		$file     = DIR_TESTDATA . '/uploads/dashicons.woff';
-		$filename = 'dashicons.woff';
-
-		$woff_mime_type = 'application/font-woff';
-
-		/*
-		 * As of PHP 8.1.12, which includes libmagic/file update to version 5.42,
-		 * the expected mime type for WOFF files is 'font/woff'.
-		 *
-		 * See https://github.com/php/php-src/issues/8805.
-		 */
-		if ( PHP_VERSION_ID >= 80112 ) {
-			$woff_mime_type = 'font/woff';
-		}
-
-		$expected = array(
-			'ext'             => 'woff',
-			'type'            => $woff_mime_type,
-			'proper_filename' => false,
-		);
-
-		add_filter(
-			'upload_mimes',
-			static function ( $mimes ) use ( $woff_mime_type ) {
-				$mimes['woff'] = $woff_mime_type;
-				return $mimes;
-			}
-		);
-
-		$this->assertSame( $expected, wp_check_filetype_and_ext( $file, $filename ) );
-	}
-
-	/**
-	 * Test file path validation
-	 *
-	 * @ticket 42016
-	 * @ticket 61488
-	 * @dataProvider data_validate_file
-	 *
-	 * @param string $file          File path.
-	 * @param array  $allowed_files List of allowed files.
-	 * @param int    $expected      Expected result.
-	 */
-	public function test_validate_file( $file, $allowed_files, $expected ) {
-		$this->assertSame( $expected, validate_file( $file, $allowed_files ) );
-	}
-
-	/**
-	 * Data provider for file validation.
-	 *
-	 * @return array {
-	 *     @type array ...$0 {
-	 *         @type string $0 File path.
-	 *         @type array  $1 List of allowed files.
-	 *         @type int    $2 Expected result.
-	 *     }
-	 * }
-	 */
-	public function data_validate_file() {
-		return array(
-
-			// Allowed files:
-			array(
-				null,
-				array(),
-				0,
-			),
-			array(
-				'',
-				array(),
-				0,
-			),
-			array(
-				' ',
-				array(),
-				0,
-			),
-			array(
-				'.',
-				array(),
-				0,
-			),
-			array(
-				'..',
-				array(),
-				0,
-			),
-			array(
-				'./',
-				array(),
-				0,
-			),
-			array(
-				'foo.ext',
-				array( 'foo.ext' ),
-				0,
-			),
-			array(
-				'dir/foo.ext',
-				array(),
-				0,
-			),
-			array(
-				'foo..ext',
-				array(),
-				0,
-			),
-			array(
-				'dir/dir/../',
-				array(),
-				0,
-			),
-
-			// Directory traversal:
-			array(
-				'../',
-				array(),
-				1,
-			),
-			array(
-				'../../',
-				array(),
-				1,
-			),
-			array(
-				'../file.ext',
-				array(),
-				1,
-			),
-			array(
-				'../dir/../',
-				array(),
-				1,
-			),
-			array(
-				'/dir/dir/../../',
-				array(),
-				1,
-			),
-			array(
-				'/dir/dir/../../',
-				array( '/dir/dir/../../' ),
-				1,
-			),
-
-			// Windows drives:
-			array(
-				'c:',
-				array(),
-				2,
-			),
-			array(
-				'C:/WINDOWS/system32',
-				array( 'C:/WINDOWS/system32' ),
-				2,
-			),
-
-			// Windows Path with allowed file
-			array(
-				'Apache24\htdocs\wordpress/wp-content/themes/twentyten/style.css',
-				array( 'Apache24\htdocs\wordpress/wp-content/themes/twentyten/style.css' ),
-				0,
-			),
-
-			// Disallowed files:
-			array(
-				'foo.ext',
-				array( 'bar.ext' ),
-				3,
-			),
-			array(
-				'foo.ext',
-				array( '.ext' ),
-				3,
-			),
-			array(
-				'path/foo.ext',
-				array( 'foo.ext' ),
-				3,
-			),
-
-		);
-	}
-
-	/**
-	 * Test stream URL validation.
-	 *
-	 * @dataProvider data_wp_is_stream
-	 *
-	 * @param string $path     The resource path or URL.
-	 * @param bool   $expected Expected result.
-	 */
-	public function test_wp_is_stream( $path, $expected ) {
-		if ( ! extension_loaded( 'openssl' ) && false !== strpos( $path, 'https://' ) ) {
-			$this->markTestSkipped( 'The openssl PHP extension is not loaded.' );
-		}
-
-		$this->assertSame( $expected, wp_is_stream( $path ) );
-	}
-
-	/**
-	 * Data provider for stream URL validation.
-	 *
-	 * @return array {
-	 *     @type array ...$0 {
-	 *         @type string $0 The resource path or URL.
-	 *         @type bool   $1 Expected result.
-	 *     }
-	 * }
-	 */
-	public function data_wp_is_stream() {
-		return array(
-			// Legitimate stream examples.
-			array( 'http://example.com', true ),
-			array( 'https://example.com', true ),
-			array( 'ftp://example.com', true ),
-			array( 'file:///path/to/some/file', true ),
-			array( 'php://some/php/file.php', true ),
-
-			// Non-stream examples.
-			array( 'fakestream://foo/bar/baz', false ),
-			array( '../../some/relative/path', false ),
-			array( 'some/other/relative/path', false ),
-			array( '/leading/relative/path', false ),
-		);
-	}
-
-	/**
-	 * Test human_readable_duration().
-	 *
-	 * @ticket 39667
-	 * @dataProvider data_human_readable_duration
-	 *
-	 * @param string $input    Duration.
-	 * @param string $expected Expected human readable duration.
-	 */
-	public function test_human_readable_duration( $input, $expected ) {
-		$this->assertSame( $expected, human_readable_duration( $input ) );
-	}
-
-	/**
-	 * Data provider for test_duration_format().
-	 *
-	 * @return array {
-	 *     @type array {
-	 *         @type string $input  Duration.
-	 *         @type string $expect Expected human readable duration.
-	 *     }
-	 * }
-	 */
-	public function data_human_readable_duration() {
-		return array(
-			// Valid ii:ss cases.
-			array( '0:0', '0 minutes, 0 seconds' ),
-			array( '00:00', '0 minutes, 0 seconds' ),
-			array( '0:5', '0 minutes, 5 seconds' ),
-			array( '0:05', '0 minutes, 5 seconds' ),
-			array( '01:01', '1 minute, 1 second' ),
-			array( '30:00', '30 minutes, 0 seconds' ),
-			array( ' 30:00 ', '30 minutes, 0 seconds' ),
-			// Valid HH:ii:ss cases.
-			array( '0:0:0', '0 hours, 0 minutes, 0 seconds' ),
-			array( '00:00:00', '0 hours, 0 minutes, 0 seconds' ),
-			array( '00:30:34', '0 hours, 30 minutes, 34 seconds' ),
-			array( '01:01:01', '1 hour, 1 minute, 1 second' ),
-			array( '1:02:00', '1 hour, 2 minutes, 0 seconds' ),
-			array( '10:30:34', '10 hours, 30 minutes, 34 seconds' ),
-			array( '1234567890:59:59', '1234567890 hours, 59 minutes, 59 seconds' ),
-			// Valid ii:ss cases with negative sign.
-			array( '-00:00', '0 minutes, 0 seconds' ),
-			array( '-3:00', '3 minutes, 0 seconds' ),
-			array( '-03:00', '3 minutes, 0 seconds' ),
-			array( '-30:00', '30 minutes, 0 seconds' ),
-			// Valid HH:ii:ss cases with negative sign.
-			array( '-00:00:00', '0 hours, 0 minutes, 0 seconds' ),
-			array( '-1:02:00', '1 hour, 2 minutes, 0 seconds' ),
-			// Invalid cases.
-			array( null, false ),
-			array( '', false ),
-			array( ':', false ),
-			array( '::', false ),
-			array( array(), false ),
-			array( 'Batman Begins !', false ),
-			array( '', false ),
-			array( '-1', false ),
-			array( -1, false ),
-			array( 0, false ),
-			array( 1, false ),
-			array( '00', false ),
-			array( '30:-10', false ),
-			array( ':30:00', false ),   // Missing HH.
-			array( 'MM:30:00', false ), // Invalid HH.
-			array( '30:MM:00', false ), // Invalid ii.
-			array( '30:30:MM', false ), // Invalid ss.
-			array( '30:MM', false ),    // Invalid ss.
-			array( 'MM:00', false ),    // Invalid ii.
-			array( 'MM:MM', false ),    // Invalid ii and ss.
-			array( '10 :30', false ),   // Containing a space.
-			array( '59:61', false ),    // Out of bound.
-			array( '61:59', false ),    // Out of bound.
-			array( '3:59:61', false ),  // Out of bound.
-			array( '03:61:59', false ), // Out of bound.
-		);
-	}
-
-	/**
-	 * @ticket 49404
-	 * @dataProvider data_wp_is_json_media_type
-	 */
-	public function test_wp_is_json_media_type( $input, $expected ) {
-		$this->assertSame( $expected, wp_is_json_media_type( $input ) );
-	}
-
-
-	public function data_wp_is_json_media_type() {
-		return array(
-			array( 'application/ld+json', true ),
-			array( 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"', true ),
-			array( 'application/activity+json', true ),
-			array( 'application/json+oembed', true ),
-			array( 'application/json', true ),
-			array( 'application/nojson', false ),
-			array( 'application/no.json', false ),
-			array( 'text/html, application/xhtml+xml, application/xml;q=0.9, image/webp, */*;q=0.8', false ),
-			array( 'application/activity+json, application/nojson', true ),
-		);
-	}
-
-	/**
-	 * @ticket 53668
-	 */
-	public function test_wp_get_default_extension_for_mime_type() {
-		$this->assertSame( 'jpg', wp_get_default_extension_for_mime_type( 'image/jpeg' ), 'jpg not returned as default extension for "image/jpeg"' );
-		$this->assertNotEquals( 'jpeg', wp_get_default_extension_for_mime_type( 'image/jpeg' ), 'jpeg should not be returned as default extension for "image/jpeg"' );
-		$this->assertSame( 'png', wp_get_default_extension_for_mime_type( 'image/png' ), 'png not returned as default extension for "image/png"' );
-		$this->assertFalse( wp_get_default_extension_for_mime_type( 'wibble/wobble' ), 'false not returned for unrecognized mime type' );
-		$this->assertFalse( wp_get_default_extension_for_mime_type( '' ), 'false not returned when empty string as mime type supplied' );
-		$this->assertFalse( wp_get_default_extension_for_mime_type( '   ' ), 'false not returned when empty string as mime type supplied' );
-		$this->assertFalse( wp_get_default_extension_for_mime_type( 123 ), 'false not returned when int as mime type supplied' );
-		$this->assertFalse( wp_get_default_extension_for_mime_type( null ), 'false not returned when null as mime type supplied' );
-	}
-
-	/**
-	 * @ticket 55505
-	 * @covers ::wp_recursive_ksort
-	 */
-	public function test_wp_recursive_ksort() {
-		// Create an array to test.
-		$theme_json = array(
-			'version'  => 1,
-			'settings' => array(
-				'typography' => array(
-					'fontFamilies' => array(
-						'fontFamily' => 'DM Sans, sans-serif',
-						'slug'       => 'dm-sans',
-						'name'       => 'DM Sans',
-					),
-				),
-				'color'      => array(
-					'palette' => array(
-						array(
-							'slug'  => 'foreground',
-							'color' => '#242321',
-							'name'  => 'Foreground',
-						),
-						array(
-							'slug'  => 'background',
-							'color' => '#FCFBF8',
-							'name'  => 'Background',
-						),
-						array(
-							'slug'  => 'primary',
-							'color' => '#71706E',
-							'name'  => 'Primary',
-						),
-						array(
-							'slug'  => 'tertiary',
-							'color' => '#CFCFCF',
-							'name'  => 'Tertiary',
-						),
-					),
-				),
-			),
-		);
-
-		// Sort the array.
-		wp_recursive_ksort( $theme_json );
-
-		// Expected result.
-		$expected_theme_json = array(
-			'settings' => array(
-				'color'      => array(
-					'palette' => array(
-						array(
-							'color' => '#242321',
-							'name'  => 'Foreground',
-							'slug'  => 'foreground',
-						),
-						array(
-							'color' => '#FCFBF8',
-							'name'  => 'Background',
-							'slug'  => 'background',
-						),
-						array(
-							'color' => '#71706E',
-							'name'  => 'Primary',
-							'slug'  => 'primary',
-						),
-						array(
-							'color' => '#CFCFCF',
-							'name'  => 'Tertiary',
-							'slug'  => 'tertiary',
-						),
-					),
-				),
-				'typography' => array(
-					'fontFamilies' => array(
-						'fontFamily' => 'DM Sans, sans-serif',
-						'name'       => 'DM Sans',
-						'slug'       => 'dm-sans',
-					),
-				),
-			),
-			'version'  => 1,
-		);
-		$this->assertSameSetsWithIndex( $theme_json, $expected_theme_json );
-	}
-}
diff --git a/tests/phpunit/tests/functions/addQueryArg.php b/tests/phpunit/tests/functions/addQueryArg.php
new file mode 100644
index 0000000000000..d6d808145de3a
--- /dev/null
+++ b/tests/phpunit/tests/functions/addQueryArg.php
@@ -0,0 +1,271 @@
+<?php
+
+/**
+ * @group functions
+ * @group add_query_arg
+ *
+ * @covers ::add_query_arg
+ */
+class Tests_Functions_AddQueryArg extends WP_UnitTestCase {
+
+	public function test_add_query_arg() {
+		$old_req_uri = $_SERVER['REQUEST_URI'];
+
+		$urls = array(
+			'/',
+			'/2012/07/30/',
+			'edit.php',
+			admin_url( 'edit.php' ),
+			admin_url( 'edit.php', 'https' ),
+		);
+
+		$frag_urls = array(
+			'/#frag',
+			'/2012/07/30/#frag',
+			'edit.php#frag',
+			admin_url( 'edit.php#frag' ),
+			admin_url( 'edit.php#frag', 'https' ),
+		);
+
+		foreach ( $urls as $url ) {
+			$_SERVER['REQUEST_URI'] = 'nothing';
+
+			$this->assertSame( "$url?foo=1", add_query_arg( 'foo', '1', $url ) );
+			$this->assertSame( "$url?foo=1", add_query_arg( array( 'foo' => '1' ), $url ) );
+			$this->assertSame(
+				"$url?foo=2",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'foo' => '2',
+					),
+					$url
+				)
+			);
+			$this->assertSame(
+				"$url?foo=1&bar=2",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'bar' => '2',
+					),
+					$url
+				)
+			);
+
+			$_SERVER['REQUEST_URI'] = $url;
+
+			$this->assertSame( "$url?foo=1", add_query_arg( 'foo', '1' ) );
+			$this->assertSame( "$url?foo=1", add_query_arg( array( 'foo' => '1' ) ) );
+			$this->assertSame(
+				"$url?foo=2",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'foo' => '2',
+					)
+				)
+			);
+			$this->assertSame(
+				"$url?foo=1&bar=2",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'bar' => '2',
+					)
+				)
+			);
+		}
+
+		foreach ( $frag_urls as $frag_url ) {
+			$_SERVER['REQUEST_URI'] = 'nothing';
+			$url                    = str_replace( '#frag', '', $frag_url );
+
+			$this->assertSame( "$url?foo=1#frag", add_query_arg( 'foo', '1', $frag_url ) );
+			$this->assertSame( "$url?foo=1#frag", add_query_arg( array( 'foo' => '1' ), $frag_url ) );
+			$this->assertSame(
+				"$url?foo=2#frag",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'foo' => '2',
+					),
+					$frag_url
+				)
+			);
+			$this->assertSame(
+				"$url?foo=1&bar=2#frag",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'bar' => '2',
+					),
+					$frag_url
+				)
+			);
+
+			$_SERVER['REQUEST_URI'] = $frag_url;
+
+			$this->assertSame( "$url?foo=1#frag", add_query_arg( 'foo', '1' ) );
+			$this->assertSame( "$url?foo=1#frag", add_query_arg( array( 'foo' => '1' ) ) );
+			$this->assertSame(
+				"$url?foo=2#frag",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'foo' => '2',
+					)
+				)
+			);
+			$this->assertSame(
+				"$url?foo=1&bar=2#frag",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'bar' => '2',
+					)
+				)
+			);
+		}
+
+		$qs_urls = array(
+			'baz=1', // #WP4903
+			'/?baz',
+			'/2012/07/30/?baz',
+			'edit.php?baz',
+			admin_url( 'edit.php?baz' ),
+			admin_url( 'edit.php?baz', 'https' ),
+			admin_url( 'edit.php?baz&za=1' ),
+			admin_url( 'edit.php?baz=1&za=1' ),
+			admin_url( 'edit.php?baz=0&za=0' ),
+		);
+
+		foreach ( $qs_urls as $url ) {
+			$_SERVER['REQUEST_URI'] = 'nothing';
+
+			$this->assertSame( "$url&foo=1", add_query_arg( 'foo', '1', $url ) );
+			$this->assertSame( "$url&foo=1", add_query_arg( array( 'foo' => '1' ), $url ) );
+			$this->assertSame(
+				"$url&foo=2",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'foo' => '2',
+					),
+					$url
+				)
+			);
+			$this->assertSame(
+				"$url&foo=1&bar=2",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'bar' => '2',
+					),
+					$url
+				)
+			);
+
+			$_SERVER['REQUEST_URI'] = $url;
+
+			$this->assertSame( "$url&foo=1", add_query_arg( 'foo', '1' ) );
+			$this->assertSame( "$url&foo=1", add_query_arg( array( 'foo' => '1' ) ) );
+			$this->assertSame(
+				"$url&foo=2",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'foo' => '2',
+					)
+				)
+			);
+			$this->assertSame(
+				"$url&foo=1&bar=2",
+				add_query_arg(
+					array(
+						'foo' => '1',
+						'bar' => '2',
+					)
+				)
+			);
+		}
+
+		$_SERVER['REQUEST_URI'] = $old_req_uri;
+	}
+
+	/**
+	 * @ticket 31306
+	 */
+	public function test_add_query_arg_numeric_keys() {
+		$url = add_query_arg( array( 'foo' => 'bar' ), '1=1' );
+		$this->assertSame( '1=1&foo=bar', $url );
+
+		$url = add_query_arg(
+			array(
+				'foo' => 'bar',
+				'1'   => '2',
+			),
+			'1=1'
+		);
+		$this->assertSame( '1=2&foo=bar', $url );
+
+		$url = add_query_arg( array( '1' => '2' ), 'foo=bar' );
+		$this->assertSame( 'foo=bar&1=2', $url );
+	}
+
+	/**
+	 * Tests that add_query_arg removes the question mark when
+	 * a parameter is set to false.
+	 *
+	 * @dataProvider data_add_query_arg_removes_question_mark
+	 *
+	 * @ticket 44499
+	 * @group  add_query_arg
+	 *
+	 * @covers ::add_query_arg
+	 *
+	 * @param string $url      Url to test.
+	 * @param string $expected Expected URL.
+	 */
+	public function test_add_query_arg_removes_question_mark( $url, $expected, $key = 'param', $value = false ) {
+		$this->assertSame( $expected, add_query_arg( $key, $value, $url ) );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array
+	 */
+	public function data_add_query_arg_removes_question_mark() {
+		return array(
+			'anchor'                                     => array(
+				'url'      => 'http://example.org?#anchor',
+				'expected' => 'http://example.org#anchor',
+			),
+			'/ then anchor'                              => array(
+				'url'      => 'http://example.org/?#anchor',
+				'expected' => 'http://example.org/#anchor',
+			),
+			'invalid query param and anchor'             => array(
+				'url'      => 'http://example.org?param=value#anchor',
+				'expected' => 'http://example.org#anchor',
+			),
+			'/ then invalid query param and anchor'      => array(
+				'url'      => 'http://example.org/?param=value#anchor',
+				'expected' => 'http://example.org/#anchor',
+			),
+			'?#anchor when adding valid key/value args'  => array(
+				'url'      => 'http://example.org?#anchor',
+				'expected' => 'http://example.org?foo=bar#anchor',
+				'key'      => 'foo',
+				'value'    => 'bar',
+			),
+			'/?#anchor when adding valid key/value args' => array(
+				'url'      => 'http://example.org/?#anchor',
+				'expected' => 'http://example.org/?foo=bar#anchor',
+				'key'      => 'foo',
+				'value'    => 'bar',
+			),
+		);
+	}
+}
diff --git a/tests/phpunit/tests/functions/boolFromYn.php b/tests/phpunit/tests/functions/boolFromYn.php
new file mode 100644
index 0000000000000..129b83de54eb4
--- /dev/null
+++ b/tests/phpunit/tests/functions/boolFromYn.php
@@ -0,0 +1,17 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::bool_from_yn
+ */
+class Tests_Functions_BoolFromYn extends WP_UnitTestCase {
+	/**
+	 * @ticket 35972
+	 */
+	public function test_bool_from_yn() {
+		$this->assertTrue( bool_from_yn( 'Y' ) );
+		$this->assertTrue( bool_from_yn( 'y' ) );
+		$this->assertFalse( bool_from_yn( 'n' ) );
+	}
+}
diff --git a/tests/phpunit/tests/functions/canonicalCharset.php b/tests/phpunit/tests/functions/canonicalCharset.php
index b46b6f5ce5b42..16207456f7cad 100644
--- a/tests/phpunit/tests/functions/canonicalCharset.php
+++ b/tests/phpunit/tests/functions/canonicalCharset.php
@@ -1,10 +1,6 @@
 <?php
 
 /**
- * Validate that badly named charsets always return the correct format for UTF-8 and ISO-8859-1.
- *
- * @since 4.8.0
- *
  * @group functions
  *
  * @covers ::_canonical_charset
@@ -62,10 +58,8 @@ public static function data_charset_normalizations() {
 
 	/**
 	 * @ticket 23688
-	 *
-	 * @covers ::get_option
 	 */
-	public function test_update_option_blog_charset() {
+	public function test_canonical_charset() {
 		$orig_blog_charset = get_option( 'blog_charset' );
 
 		update_option( 'blog_charset', 'utf8' );
diff --git a/tests/phpunit/tests/date/currentDatetime.php b/tests/phpunit/tests/functions/currentDatetime.php
similarity index 100%
rename from tests/phpunit/tests/date/currentDatetime.php
rename to tests/phpunit/tests/functions/currentDatetime.php
diff --git a/tests/phpunit/tests/date/currentTime.php b/tests/phpunit/tests/functions/currentTime.php
similarity index 100%
rename from tests/phpunit/tests/date/currentTime.php
rename to tests/phpunit/tests/functions/currentTime.php
diff --git a/tests/phpunit/tests/date/dateI18n.php b/tests/phpunit/tests/functions/dateI18n.php
similarity index 100%
rename from tests/phpunit/tests/date/dateI18n.php
rename to tests/phpunit/tests/functions/dateI18n.php
diff --git a/tests/phpunit/tests/functions/deviceCanUpload.php b/tests/phpunit/tests/functions/deviceCanUpload.php
new file mode 100644
index 0000000000000..59b4a14d98752
--- /dev/null
+++ b/tests/phpunit/tests/functions/deviceCanUpload.php
@@ -0,0 +1,68 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::_device_can_upload
+ */
+class Tests_Functions_DeviceCanUpload extends WP_UnitTestCase {
+	/**
+	 * @dataProvider data_device_can_upload
+	 */
+	public function test_device_can_upload( $user_agent, $expected ) {
+		$_SERVER['HTTP_USER_AGENT'] = $user_agent;
+		$actual                     = _device_can_upload();
+		unset( $_SERVER['HTTP_USER_AGENT'] );
+		$this->assertSame( $expected, $actual );
+	}
+
+	public function data_device_can_upload() {
+		return array(
+			// iPhone iOS 5.0.1, Safari 5.1.
+			array(
+				'Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Mobile/9A406)',
+				false,
+			),
+			// iPad iOS 3.2, Safari 4.0.4.
+			array(
+				'Mozilla/5.0 (iPad; U; CPU OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B334b Safari/531.21.10',
+				false,
+			),
+			// iPod iOS 4.3.3, Safari 5.0.2.
+			array(
+				'Mozilla/5.0 (iPod; U; CPU iPhone OS 4_3_3 like Mac OS X; ja-jp) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8J2 Safari/6533.18.5',
+				false,
+			),
+			// iPhone iOS 6.0.0, Safari 6.0.
+			array(
+				'Mozilla/5.0 (iPhone; CPU iPhone OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25',
+				true,
+			),
+			// iPad iOS 6.0.0, Safari 6.0.
+			array(
+				'Mozilla/5.0 (iPad; CPU OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25',
+				true,
+			),
+			// Android 2.2, Android Webkit Browser.
+			array(
+				'Mozilla/5.0 (Android 2.2; Windows; U; Windows NT 6.1; en-US) AppleWebKit/533.19.4 (KHTML, like Gecko) Version/5.0.3 Safari/533.19.4',
+				true,
+			),
+			// BlackBerry 9900, BlackBerry browser.
+			array(
+				'Mozilla/5.0 (BlackBerry; U; BlackBerry 9900; en) AppleWebKit/534.11+ (KHTML, like Gecko) Version/7.1.0.346 Mobile Safari/534.11+',
+				true,
+			),
+			// Windows Phone 8.0, Internet Explorer 10.0.
+			array(
+				'Mozilla/5.0 (compatible; MSIE 10.0; Windows Phone 8.0; Trident/6.0; IEMobile/10.0; ARM; Touch; NOKIA; Lumia 920)',
+				true,
+			),
+			// Ubuntu desktop, Firefox 41.0.
+			array(
+				'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:41.0) Gecko/20100101 Firefox/41.0',
+				true,
+			),
+		);
+	}
+}
diff --git a/tests/phpunit/tests/functions/getAllowedMimeTypes.php b/tests/phpunit/tests/functions/getAllowedMimeTypes.php
new file mode 100644
index 0000000000000..dd387498d2893
--- /dev/null
+++ b/tests/phpunit/tests/functions/getAllowedMimeTypes.php
@@ -0,0 +1,28 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::get_allowed_mime_types
+ */
+class Tests_Functions_GetAllowedMimeTypes extends WP_UnitTestCase {
+	/**
+	 * @ticket 21594
+	 */
+	public function test_get_allowed_mime_types() {
+		$mimes = get_allowed_mime_types();
+
+		$this->assertIsArray( $mimes );
+		$this->assertNotEmpty( $mimes );
+
+		add_filter( 'upload_mimes', '__return_empty_array' );
+		$mimes = get_allowed_mime_types();
+		$this->assertIsArray( $mimes );
+		$this->assertEmpty( $mimes );
+
+		remove_filter( 'upload_mimes', '__return_empty_array' );
+		$mimes = get_allowed_mime_types();
+		$this->assertIsArray( $mimes );
+		$this->assertNotEmpty( $mimes );
+	}
+}
diff --git a/tests/phpunit/tests/functions/getFileData.php b/tests/phpunit/tests/functions/getFileData.php
new file mode 100644
index 0000000000000..7ac923bc2a984
--- /dev/null
+++ b/tests/phpunit/tests/functions/getFileData.php
@@ -0,0 +1,90 @@
+<?php
+
+/**
+ * @group functions
+ * @group file
+ *
+ * @covers ::get_file_data
+ */
+class Tests_Functions_GetFileData extends WP_UnitTestCase {
+
+	/**
+	 * @group plugins
+	 * @group themes
+	 */
+	public function test_get_file_data() {
+		$theme_headers = array(
+			'Name'        => 'Theme Name',
+			'ThemeURI'    => 'Theme URI',
+			'Description' => 'Description',
+			'Version'     => 'Version',
+			'Author'      => 'Author',
+			'AuthorURI'   => 'Author URI',
+		);
+
+		$actual = get_file_data( DIR_TESTDATA . '/themedir1/default/style.css', $theme_headers );
+
+		$expected = array(
+			'Name'        => 'WordPress Default',
+			'ThemeURI'    => 'http://wordpress.org/',
+			'Description' => 'The default WordPress theme based on the famous <a href="http://binarybonsai.com/kubrick/">Kubrick</a>.',
+			'Version'     => '1.6',
+			'Author'      => 'Michael Heilemann',
+			'AuthorURI'   => 'http://binarybonsai.com/',
+		);
+
+		$this->assertNotEmpty( $actual );
+
+		foreach ( $actual as $header => $value ) {
+			$this->assertSame( $expected[ $header ], $value, $header );
+		}
+	}
+
+	/**
+	 * @ticket 19854
+	 * @group plugins
+	 * @group themes
+	 */
+	public function test_get_file_data_with_cr_line_endings() {
+		$headers = array(
+			'SomeHeader'  => 'Some Header',
+			'Description' => 'Description',
+			'Author'      => 'Author',
+		);
+
+		$actual   = get_file_data( DIR_TESTDATA . '/formatting/file-header-cr-line-endings.php', $headers );
+		$expected = array(
+			'SomeHeader'  => 'Some header value!',
+			'Description' => 'This file is using CR line endings for a testcase.',
+			'Author'      => 'A Very Old Mac',
+		);
+
+		$this->assertNotEmpty( $actual );
+
+		foreach ( $actual as $header => $value ) {
+			$this->assertSame( $expected[ $header ], $value, $header );
+		}
+	}
+
+	/**
+	 * @ticket 47186
+	 * @group plugins
+	 * @group themes
+	 */
+	public function test_get_file_data_with_php_open_tag_prefix() {
+		$headers = array(
+			'TemplateName' => 'Template Name',
+		);
+
+		$actual   = get_file_data( DIR_TESTDATA . '/formatting/file-header-php-open-tag-prefix.php', $headers );
+		$expected = array(
+			'TemplateName' => 'Something',
+		);
+
+		$this->assertNotEmpty( $actual );
+
+		foreach ( $actual as $header => $value ) {
+			$this->assertSame( $expected[ $header ], $value, $header );
+		}
+	}
+}
diff --git a/tests/phpunit/tests/functions/humanReadableDuration.php b/tests/phpunit/tests/functions/humanReadableDuration.php
new file mode 100644
index 0000000000000..a567d568aaa93
--- /dev/null
+++ b/tests/phpunit/tests/functions/humanReadableDuration.php
@@ -0,0 +1,90 @@
+<?php
+
+/**
+ * @ticket 65526
+ *
+ * @group date
+ * @group functions
+ *
+ * @covers ::human_readable_duration
+ */
+class Tests_Functions_HumanReadableDuration extends WP_UnitTestCase {
+
+	/**
+	 * Test human_readable_duration().
+	 *
+	 * @ticket 39667
+	 * @dataProvider data_human_readable_duration
+	 *
+	 * @param string $input    Duration.
+	 * @param string $expected Expected human readable duration.
+	 */
+	public function test_human_readable_duration( $input, $expected ) {
+		$this->assertSame( $expected, human_readable_duration( $input ) );
+	}
+
+	/**
+	 * Data provider for test_human_readable_duration().
+	 *
+	 * @return array {
+	 *     @type array {
+	 *         @type string $input  Duration.
+	 *         @type string $expect Expected human readable duration.
+	 *     }
+	 * }
+	 */
+	public function data_human_readable_duration() {
+		return array(
+			// Valid ii:ss cases.
+			array( '0:0', '0 minutes, 0 seconds' ),
+			array( '00:00', '0 minutes, 0 seconds' ),
+			array( '0:5', '0 minutes, 5 seconds' ),
+			array( '0:05', '0 minutes, 5 seconds' ),
+			array( '01:01', '1 minute, 1 second' ),
+			array( '30:00', '30 minutes, 0 seconds' ),
+			array( ' 30:00 ', '30 minutes, 0 seconds' ),
+			// Valid HH:ii:ss cases.
+			array( '0:0:0', '0 hours, 0 minutes, 0 seconds' ),
+			array( '00:00:00', '0 hours, 0 minutes, 0 seconds' ),
+			array( '00:30:34', '0 hours, 30 minutes, 34 seconds' ),
+			array( '01:01:01', '1 hour, 1 minute, 1 second' ),
+			array( '1:02:00', '1 hour, 2 minutes, 0 seconds' ),
+			array( '10:30:34', '10 hours, 30 minutes, 34 seconds' ),
+			array( '1234567890:59:59', '1234567890 hours, 59 minutes, 59 seconds' ),
+			// Valid ii:ss cases with negative sign.
+			array( '-00:00', '0 minutes, 0 seconds' ),
+			array( '-3:00', '3 minutes, 0 seconds' ),
+			array( '-03:00', '3 minutes, 0 seconds' ),
+			array( '-30:00', '30 minutes, 0 seconds' ),
+			// Valid HH:ii:ss cases with negative sign.
+			array( '-00:00:00', '0 hours, 0 minutes, 0 seconds' ),
+			array( '-1:02:00', '1 hour, 2 minutes, 0 seconds' ),
+			// Invalid cases.
+			array( null, false ),
+			array( '', false ),
+			array( ':', false ),
+			array( '::', false ),
+			array( array(), false ),
+			array( 'Batman Begins !', false ),
+			array( '', false ),
+			array( '-1', false ),
+			array( -1, false ),
+			array( 0, false ),
+			array( 1, false ),
+			array( '00', false ),
+			array( '30:-10', false ),
+			array( ':30:00', false ),   // Missing HH.
+			array( 'MM:30:00', false ), // Invalid HH.
+			array( '30:MM:00', false ), // Invalid ii.
+			array( '30:30:MM', false ), // Invalid ss.
+			array( '30:MM', false ),    // Invalid ss.
+			array( 'MM:00', false ),    // Invalid ii.
+			array( 'MM:MM', false ),    // Invalid ii and ss.
+			array( '10 :30', false ),   // Containing a space.
+			array( '59:61', false ),    // Out of bound.
+			array( '61:59', false ),    // Out of bound.
+			array( '3:59:61', false ),  // Out of bound.
+			array( '03:61:59', false ), // Out of bound.
+		);
+	}
+}
diff --git a/tests/phpunit/tests/date/mysql2date.php b/tests/phpunit/tests/functions/mysql2date.php
similarity index 100%
rename from tests/phpunit/tests/date/mysql2date.php
rename to tests/phpunit/tests/functions/mysql2date.php
diff --git a/tests/phpunit/tests/functions/mysqlToRfc3339.php b/tests/phpunit/tests/functions/mysqlToRfc3339.php
new file mode 100644
index 0000000000000..6c71d5991f047
--- /dev/null
+++ b/tests/phpunit/tests/functions/mysqlToRfc3339.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::mysql_to_rfc3339
+ */
+class Tests_Functions_MysqlToRfc3339 extends WP_UnitTestCase {
+	/**
+	 * @ticket 36054
+	 * @dataProvider data_mysql_to_rfc3339
+	 */
+	public function test_mysql_to_rfc3339( $expected, $actual ) {
+		$date_return = mysql_to_rfc3339( $actual );
+
+		$this->assertIsString( $date_return, 'The date return must be a string' );
+		$this->assertNotEmpty( $date_return, 'The date return could not be an empty string' );
+		$this->assertSame( $expected, $date_return, 'The date does not match' );
+		$this->assertEquals( new DateTime( $expected ), new DateTime( $date_return ), 'The date is not the same after the call method' );
+	}
+
+	public function data_mysql_to_rfc3339() {
+		return array(
+			array( '2016-03-15T18:54:46', '15-03-2016 18:54:46' ),
+			array( '2016-03-02T19:13:25', '2016-03-02 19:13:25' ),
+			array( '2016-03-02T19:13:00', '2016-03-02 19:13' ),
+			array( '2016-03-02T19:13:00', '16-03-02 19:13' ),
+			array( '2016-03-02T19:13:00', '16-03-02 19:13' ),
+		);
+	}
+}
diff --git a/tests/phpunit/tests/functions/pathIsAbsolute.php b/tests/phpunit/tests/functions/pathIsAbsolute.php
new file mode 100644
index 0000000000000..edd0acd2cc393
--- /dev/null
+++ b/tests/phpunit/tests/functions/pathIsAbsolute.php
@@ -0,0 +1,47 @@
+<?php
+
+/**
+ * @ticket 65526
+ *
+ * @group functions
+ *
+ * @covers ::path_is_absolute
+ */
+class Tests_Functions_PathIsAbsolute extends WP_UnitTestCase {
+
+	public function test_path_is_absolute() {
+		$absolute_paths = array(
+			'/',
+			'/foo/',
+			'/foo',
+			'/FOO/bar',
+			'/foo/bar/',
+			'/foo/../bar/',
+			'\\WINDOWS',
+			'C:\\',
+			'C:\\WINDOWS',
+			'\\\\sambashare\\foo',
+		);
+		foreach ( $absolute_paths as $path ) {
+			$this->assertTrue( path_is_absolute( $path ), "path_is_absolute('$path') should return true" );
+		}
+	}
+
+	public function test_path_is_not_absolute() {
+		$relative_paths = array(
+			'',
+			'.',
+			'..',
+			'../foo',
+			'../',
+			'../foo.bar',
+			'foo/bar',
+			'foo',
+			'FOO',
+			'..\\WINDOWS',
+		);
+		foreach ( $relative_paths as $path ) {
+			$this->assertFalse( path_is_absolute( $path ), "path_is_absolute('$path') should return false" );
+		}
+	}
+}
diff --git a/tests/phpunit/tests/functions/pathJoin.php b/tests/phpunit/tests/functions/pathJoin.php
new file mode 100644
index 0000000000000..406e36919b88f
--- /dev/null
+++ b/tests/phpunit/tests/functions/pathJoin.php
@@ -0,0 +1,73 @@
+<?php
+
+/**
+ * @ticket 65526
+ *
+ * @group functions
+ *
+ * @covers ::path_join
+ */
+class Tests_Functions_PathJoin extends WP_UnitTestCase {
+
+	/**
+	 * Tests path_join().
+	 *
+	 * @ticket 55897
+	 * @dataProvider data_path_join
+	 */
+	public function test_path_join( $base, $path, $expected ) {
+		$this->assertSame( $expected, path_join( $base, $path ) );
+	}
+
+	/**
+	 * Data provider for test_path_join().
+	 *
+	 * @return string[][]
+	 */
+	public function data_path_join() {
+		return array(
+			// Absolute paths.
+			'absolute path should return path' => array(
+				'base'     => 'base',
+				'path'     => '/path',
+				'expected' => '/path',
+			),
+			'windows path with slashes'        => array(
+				'base'     => 'base',
+				'path'     => '//path',
+				'expected' => '//path',
+			),
+			'windows path with backslashes'    => array(
+				'base'     => 'base',
+				'path'     => '\\\\path',
+				'expected' => '\\\\path',
+			),
+			// Non-absolute paths.
+			'join base and path'               => array(
+				'base'     => 'base',
+				'path'     => 'path',
+				'expected' => 'base/path',
+			),
+			'strip trailing slashes in base'   => array(
+				'base'     => 'base///',
+				'path'     => 'path',
+				'expected' => 'base/path',
+			),
+			'empty path'                       => array(
+				'base'     => 'base',
+				'path'     => '',
+				'expected' => 'base/',
+			),
+			'empty base'                       => array(
+				'base'     => '',
+				'path'     => 'path',
+				'expected' => '/path',
+			),
+			'empty path and base'              => array(
+				'base'     => '',
+				'path'     => '',
+				'expected' => '/',
+			),
+		);
+	}
+}
diff --git a/tests/phpunit/tests/functions/validateFile.php b/tests/phpunit/tests/functions/validateFile.php
new file mode 100644
index 0000000000000..8c634563ef6cc
--- /dev/null
+++ b/tests/phpunit/tests/functions/validateFile.php
@@ -0,0 +1,161 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::validate_file
+ */
+class Tests_Functions_ValidateFile extends WP_UnitTestCase {
+
+	/**
+	 * Test file path validation
+	 *
+	 * @ticket 42016
+	 * @ticket 61488
+	 * @dataProvider data_validate_file
+	 *
+	 * @param string $file          File path.
+	 * @param array  $allowed_files List of allowed files.
+	 * @param int    $expected      Expected result.
+	 */
+	public function test_validate_file( $file, $allowed_files, $expected ) {
+		$this->assertSame( $expected, validate_file( $file, $allowed_files ) );
+	}
+
+	/**
+	 * Data provider for file validation.
+	 *
+	 * @return array {
+	 *     @type array ...$0 {
+	 *         @type string $0 File path.
+	 *         @type array  $1 List of allowed files.
+	 *         @type int    $2 Expected result.
+	 *     }
+	 * }
+	 */
+	public function data_validate_file() {
+		return array(
+
+			// Allowed files:
+			array(
+				null,
+				array(),
+				0,
+			),
+			array(
+				'',
+				array(),
+				0,
+			),
+			array(
+				' ',
+				array(),
+				0,
+			),
+			array(
+				'.',
+				array(),
+				0,
+			),
+			array(
+				'..',
+				array(),
+				0,
+			),
+			array(
+				'./',
+				array(),
+				0,
+			),
+			array(
+				'foo.ext',
+				array( 'foo.ext' ),
+				0,
+			),
+			array(
+				'dir/foo.ext',
+				array(),
+				0,
+			),
+			array(
+				'foo..ext',
+				array(),
+				0,
+			),
+			array(
+				'dir/dir/../',
+				array(),
+				0,
+			),
+
+			// Directory traversal:
+			array(
+				'../',
+				array(),
+				1,
+			),
+			array(
+				'../../',
+				array(),
+				1,
+			),
+			array(
+				'../file.ext',
+				array(),
+				1,
+			),
+			array(
+				'../dir/../',
+				array(),
+				1,
+			),
+			array(
+				'/dir/dir/../../',
+				array(),
+				1,
+			),
+			array(
+				'/dir/dir/../../',
+				array( '/dir/dir/../../' ),
+				1,
+			),
+
+			// Windows drives:
+			array(
+				'c:',
+				array(),
+				2,
+			),
+			array(
+				'C:/WINDOWS/system32',
+				array( 'C:/WINDOWS/system32' ),
+				2,
+			),
+
+			// Windows Path with allowed file
+			array(
+				'Apache24\htdocs\wordpress/wp-content/themes/twentyten/style.css',
+				array( 'Apache24\htdocs\wordpress/wp-content/themes/twentyten/style.css' ),
+				0,
+			),
+
+			// Disallowed files:
+			array(
+				'foo.ext',
+				array( 'bar.ext' ),
+				3,
+			),
+			array(
+				'foo.ext',
+				array( '.ext' ),
+				3,
+			),
+			array(
+				'path/foo.ext',
+				array( 'foo.ext' ),
+				3,
+			),
+
+		);
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpCheckFiletypeAndExt.php b/tests/phpunit/tests/functions/wpCheckFiletypeAndExt.php
new file mode 100644
index 0000000000000..4b30be2891334
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpCheckFiletypeAndExt.php
@@ -0,0 +1,258 @@
+<?php
+
+/**
+ * @group functions
+ * @group upload
+ *
+ * @covers ::wp_check_filetype_and_ext
+ */
+class Tests_Functions_WpCheckFiletypeAndExt extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 39550
+	 * @dataProvider data_wp_check_filetype_and_ext
+	 * @requires extension fileinfo
+	 */
+	public function test_wp_check_filetype_and_ext( $file, $filename, $expected ) {
+		$this->assertSame( $expected, wp_check_filetype_and_ext( $file, $filename ) );
+	}
+
+	public function data_wp_check_filetype_and_ext() {
+		$data = array(
+			// Standard image.
+			array(
+				DIR_TESTDATA . '/images/canola.jpg',
+				'canola.jpg',
+				array(
+					'ext'             => 'jpg',
+					'type'            => 'image/jpeg',
+					'proper_filename' => false,
+				),
+			),
+			// Image with wrong extension.
+			array(
+				DIR_TESTDATA . '/images/test-image-mime-jpg.png',
+				'test-image-mime-jpg.png',
+				array(
+					'ext'             => 'jpg',
+					'type'            => 'image/jpeg',
+					'proper_filename' => 'test-image-mime-jpg.jpg',
+				),
+			),
+			// Image without extension.
+			array(
+				DIR_TESTDATA . '/images/test-image-no-extension',
+				'test-image-no-extension',
+				array(
+					'ext'             => false,
+					'type'            => false,
+					'proper_filename' => false,
+				),
+			),
+			// Valid non-image file with an image extension.
+			array(
+				DIR_TESTDATA . '/formatting/big5.txt',
+				'big5.jpg',
+				array(
+					'ext'             => false,
+					'type'            => false,
+					'proper_filename' => false,
+				),
+			),
+			// Non-image file not allowed.
+			array(
+				DIR_TESTDATA . '/export/crazy-cdata.xml',
+				'crazy-cdata.xml',
+				array(
+					'ext'             => false,
+					'type'            => false,
+					'proper_filename' => false,
+				),
+			),
+			// Non-image file not allowed even if it's named like one.
+			array(
+				DIR_TESTDATA . '/export/crazy-cdata.xml',
+				'crazy-cdata.jpg',
+				array(
+					'ext'             => false,
+					'type'            => false,
+					'proper_filename' => false,
+				),
+			),
+			// Non-image file not allowed if it's named like something else.
+			array(
+				DIR_TESTDATA . '/export/crazy-cdata.xml',
+				'crazy-cdata.doc',
+				array(
+					'ext'             => false,
+					'type'            => false,
+					'proper_filename' => false,
+				),
+			),
+			// Non-image file not allowed even if it's named like one.
+			array(
+				DIR_TESTDATA . '/export/crazy-cdata.xml',
+				'crazy-cdata.jpg',
+				array(
+					'ext'             => false,
+					'type'            => false,
+					'proper_filename' => false,
+				),
+			),
+			// Non-image file not allowed if it's named like something else.
+			array(
+				DIR_TESTDATA . '/export/crazy-cdata.xml',
+				'crazy-cdata.doc',
+				array(
+					'ext'             => false,
+					'type'            => false,
+					'proper_filename' => false,
+				),
+			),
+		);
+
+		// Test a few additional file types on single sites.
+		if ( ! is_multisite() ) {
+			$data = array_merge(
+				$data,
+				array(
+					// Standard non-image file.
+					array(
+						DIR_TESTDATA . '/formatting/big5.txt',
+						'big5.txt',
+						array(
+							'ext'             => 'txt',
+							'type'            => 'text/plain',
+							'proper_filename' => false,
+						),
+					),
+					// Google Docs file for which finfo_file() returns a duplicate mime type.
+					array(
+						DIR_TESTDATA . '/uploads/double-mime-type.docx',
+						'double-mime-type.docx',
+						array(
+							'ext'             => 'docx',
+							'type'            => 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+							'proper_filename' => false,
+						),
+					),
+					// Non-image file with wrong sub-type.
+					array(
+						DIR_TESTDATA . '/uploads/pages-to-word.docx',
+						'pages-to-word.docx',
+						array(
+							'ext'             => 'docx',
+							'type'            => 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
+							'proper_filename' => false,
+						),
+					),
+					// FLAC file.
+					array(
+						DIR_TESTDATA . '/uploads/small-audio.flac',
+						'small-audio.flac',
+						array(
+							'ext'             => 'flac',
+							'type'            => 'audio/flac',
+							'proper_filename' => false,
+						),
+					),
+					// Assorted text/* sample files
+					array(
+						DIR_TESTDATA . '/uploads/test.vtt',
+						'test.vtt',
+						array(
+							'ext'             => 'vtt',
+							'type'            => 'text/vtt',
+							'proper_filename' => false,
+						),
+					),
+					array(
+						DIR_TESTDATA . '/uploads/test.csv',
+						'test.csv',
+						array(
+							'ext'             => 'csv',
+							'type'            => 'text/csv',
+							'proper_filename' => false,
+						),
+					),
+					// RTF files.
+					array(
+						DIR_TESTDATA . '/uploads/test.rtf',
+						'test.rtf',
+						array(
+							'ext'             => 'rtf',
+							'type'            => 'application/rtf',
+							'proper_filename' => false,
+						),
+					),
+				)
+			);
+		}
+
+		return $data;
+	}
+
+	/**
+	 * @ticket 39550
+	 * @group ms-excluded
+	 * @requires extension fileinfo
+	 */
+	public function test_wp_check_filetype_and_ext_with_filtered_svg() {
+		$file     = DIR_TESTDATA . '/uploads/video-play.svg';
+		$filename = 'video-play.svg';
+
+		$expected = array(
+			'ext'             => 'svg',
+			'type'            => 'image/svg+xml',
+			'proper_filename' => false,
+		);
+
+		add_filter(
+			'upload_mimes',
+			static function ( $mimes ) {
+				$mimes['svg'] = 'image/svg+xml';
+				return $mimes;
+			}
+		);
+
+		$this->assertSame( $expected, wp_check_filetype_and_ext( $file, $filename ) );
+	}
+
+	/**
+	 * @ticket 39550
+	 * @group ms-excluded
+	 * @requires extension fileinfo
+	 */
+	public function test_wp_check_filetype_and_ext_with_filtered_woff() {
+		$file     = DIR_TESTDATA . '/uploads/dashicons.woff';
+		$filename = 'dashicons.woff';
+
+		$woff_mime_type = 'application/font-woff';
+
+		/*
+		 * As of PHP 8.1.12, which includes libmagic/file update to version 5.42,
+		 * the expected mime type for WOFF files is 'font/woff'.
+		 *
+		 * See https://github.com/php/php-src/issues/8805.
+		 */
+		if ( PHP_VERSION_ID >= 80112 ) {
+			$woff_mime_type = 'font/woff';
+		}
+
+		$expected = array(
+			'ext'             => 'woff',
+			'type'            => $woff_mime_type,
+			'proper_filename' => false,
+		);
+
+		add_filter(
+			'upload_mimes',
+			static function ( $mimes ) use ( $woff_mime_type ) {
+				$mimes['woff'] = $woff_mime_type;
+				return $mimes;
+			}
+		);
+
+		$this->assertSame( $expected, wp_check_filetype_and_ext( $file, $filename ) );
+	}
+}
diff --git a/tests/phpunit/tests/date/wpDate.php b/tests/phpunit/tests/functions/wpDate.php
similarity index 100%
rename from tests/phpunit/tests/date/wpDate.php
rename to tests/phpunit/tests/functions/wpDate.php
diff --git a/tests/phpunit/tests/functions/wpExt2Type.php b/tests/phpunit/tests/functions/wpExt2Type.php
new file mode 100644
index 0000000000000..d6de698f449a8
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpExt2Type.php
@@ -0,0 +1,26 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_ext2type
+ */
+class Tests_Functions_WpExt2Type extends WP_UnitTestCase {
+	/**
+	 * @ticket 35987
+	 */
+	public function test_wp_ext2type() {
+		$extensions = wp_get_ext_types();
+
+		$this->assertNotEmpty( $extensions );
+
+		foreach ( $extensions as $type => $extension_list ) {
+			foreach ( $extension_list as $extension ) {
+				$this->assertSame( $type, wp_ext2type( $extension ) );
+				$this->assertSame( $type, wp_ext2type( strtoupper( $extension ) ) );
+			}
+		}
+
+		$this->assertNull( wp_ext2type( 'unknown_format' ) );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpExtractUrls.php b/tests/phpunit/tests/functions/wpExtractUrls.php
new file mode 100644
index 0000000000000..9e36ea42cd578
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpExtractUrls.php
@@ -0,0 +1,210 @@
+<?php
+
+/**
+ * @ticket 65526
+ *
+ * @group functions
+ *
+ * @covers ::wp_extract_urls
+ */
+class Tests_Functions_wpExtractUrls extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 9064
+	 */
+	public function test_wp_extract_urls() {
+		$original_urls = array(
+			'http://woo.com/1,2,3,4,5,6/-1-2-3-4-/woo.html',
+			'http://this.com',
+			'http://127.0.0.1',
+			'http://www111.urwyeoweytwutreyytqytwetowteuiiu.com/?346236346326&2134362574863.437',
+			'http://wordpress-core/1,2,3,4,5,6/-1-2-3-4-/woo.html',
+			'http://wordpress-core.com:8080/',
+			'http://www.website.com:5000',
+			'http://wordpress-core/?346236346326&2134362574863.437',
+			'http://افغانستا.icom.museum',
+			'http://الجزائر.icom.museum',
+			'http://österreich.icom.museum',
+			'http://বাংলাদেশ.icom.museum',
+			'http://беларусь.icom.museum',
+			'http://belgië.icom.museum',
+			'http://българия.icom.museum',
+			'http://تشادر.icom.museum',
+			'http://中国.icom.museum',
+			// 'http://القمر.icom.museum',         // Comoros http://القمر.icom.museum
+			// 'http://κυπρος.icom.museum',        // Cyprus  http://κυπρος.icom.museum
+			'http://českárepublika.icom.museum',
+			// 'http://مصر.icom.museum',           // Egypt   http://مصر.icom.museum
+			'http://ελλάδα.icom.museum',
+			'http://magyarország.icom.museum',
+			'http://ísland.icom.museum',
+			'http://भारत.icom.museum',
+			'http://ايران.icom.museum',
+			'http://éire.icom.museum',
+			'http://איקו״ם.ישראל.museum',
+			'http://日本.icom.museum',
+			'http://الأردن.icom.museum',
+			'http://қазақстан.icom.museum',
+			'http://한국.icom.museum',
+			'http://кыргызстан.icom.museum',
+			'http://ລາວ.icom.museum',
+			'http://لبنان.icom.museum',
+			'http://македонија.icom.museum',
+			// 'http://موريتانيا.icom.museum',     // Mauritania http://موريتانيا.icom.museum
+			'http://méxico.icom.museum',
+			'http://монголулс.icom.museum',
+			// 'http://المغرب.icom.museum',        // Morocco    http://المغرب.icom.museum
+			'http://नेपाल.icom.museum',
+			// 'http://عمان.icom.museum',          // Oman       http://عمان.icom.museum
+			'http://قطر.icom.museum',
+			'http://românia.icom.museum',
+			'http://россия.иком.museum',
+			'http://србијаицрнагора.иком.museum',
+			'http://இலங்கை.icom.museum',
+			'http://españa.icom.museum',
+			'http://ไทย.icom.museum',
+			'http://تونس.icom.museum',
+			'http://türkiye.icom.museum',
+			'http://украина.icom.museum',
+			'http://việtnam.icom.museum',
+			'ftp://127.0.0.1/',
+			'http://www.woo.com/video?v=exvUH2qKLTU',
+			'http://taco.com?burrito=enchilada#guac',
+			'http://example.org/?post_type=post&p=4',
+			'http://example.org/?post_type=post&p=5',
+			'http://example.org/?post_type=post&p=6',
+			'http://typo-in-query.org/?foo=bar&ampbaz=missing_semicolon',
+		);
+
+		$blob = '
+			http://woo.com/1,2,3,4,5,6/-1-2-3-4-/woo.html
+
+			http://this.com
+
+			http://127.0.0.1
+
+			http://www111.urwyeoweytwutreyytqytwetowteuiiu.com/?346236346326&amp;2134362574863.437
+
+			http://wordpress-core/1,2,3,4,5,6/-1-2-3-4-/woo.html
+
+			http://wordpress-core.com:8080/
+
+			http://www.website.com:5000
+
+			http://wordpress-core/?346236346326&amp;2134362574863.437
+
+			http://افغانستا.icom.museum
+			http://الجزائر.icom.museum
+			http://österreich.icom.museum
+			http://বাংলাদেশ.icom.museum
+			http://беларусь.icom.museum
+			http://belgië.icom.museum
+			http://българия.icom.museum
+			http://تشادر.icom.museum
+			http://中国.icom.museum
+			http://českárepublika.icom.museum
+			http://ελλάδα.icom.museum
+			http://magyarország.icom.museum
+			http://ísland.icom.museum
+			http://भारत.icom.museum
+			http://ايران.icom.museum
+			http://éire.icom.museum
+			http://איקו״ם.ישראל.museum
+			http://日本.icom.museum
+			http://الأردن.icom.museum
+			http://қазақстан.icom.museum
+			http://한국.icom.museum
+			http://кыргызстан.icom.museum
+			http://ລາວ.icom.museum
+			http://لبنان.icom.museum
+			http://македонија.icom.museum
+			http://méxico.icom.museum
+			http://монголулс.icom.museum
+			http://नेपाल.icom.museum
+			http://قطر.icom.museum
+			http://românia.icom.museum
+			http://россия.иком.museum
+			http://србијаицрнагора.иком.museum
+			http://இலங்கை.icom.museum
+			http://españa.icom.museum
+			http://ไทย.icom.museum
+			http://تونس.icom.museum
+			http://türkiye.icom.museum
+			http://украина.icom.museum
+			http://việtnam.icom.museum
+			ftp://127.0.0.1/
+			http://www.woo.com/video?v=exvUH2qKLTU
+
+			http://taco.com?burrito=enchilada#guac
+
+			http://example.org/?post_type=post&amp;p=4
+			http://example.org/?post_type=post&#038;p=5
+			http://example.org/?post_type=post&p=6
+
+			http://typo-in-query.org/?foo=bar&ampbaz=missing_semicolon
+		';
+
+		$urls = wp_extract_urls( $blob );
+		$this->assertNotEmpty( $urls );
+		$this->assertIsArray( $urls );
+		$this->assertCount( count( $original_urls ), $urls );
+		$this->assertSame( $original_urls, $urls );
+
+		$exploded = array_values( array_filter( array_map( 'trim', explode( "\n", $blob ) ) ) );
+		// wp_extract_urls() calls html_entity_decode().
+		$decoded = array_map( 'html_entity_decode', $exploded );
+
+		$this->assertSame( $decoded, $urls );
+		$this->assertSame( $original_urls, $decoded );
+
+		$blob = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor
+			incididunt ut labore http://woo.com/1,2,3,4,5,6/-1-2-3-4-/woo.html et dolore magna aliqua.
+			Ut http://this.com enim ad minim veniam, quis nostrud exercitation 16.06. to 18.06.2014 ullamco http://127.0.0.1
+			laboris nisi ut aliquip ex http://www111.urwyeoweytwutreyytqytwetowteuiiu.com/?346236346326&amp;2134362574863.437 ea
+			commodo consequat. http://wordpress-core/1,2,3,4,5,6/-1-2-3-4-/woo.html Duis aute irure dolor in reprehenderit in voluptate
+			velit esse http://wordpress-core.com:8080/ cillum dolore eu fugiat nulla <A href="http://www.website.com:5000">http://www.website.com:5000</B> pariatur. Excepteur sint occaecat cupidatat non proident,
+			sunt in culpa qui officia deserunt mollit http://wordpress-core/?346236346326&amp;2134362574863.437 anim id est laborum.';
+
+		$urls = wp_extract_urls( $blob );
+		$this->assertNotEmpty( $urls );
+		$this->assertIsArray( $urls );
+		$this->assertCount( 8, $urls );
+		$this->assertSame( array_slice( $original_urls, 0, 8 ), $urls );
+
+		$blob = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor
+			incididunt ut labore <a href="http://woo.com/1,2,3,4,5,6/-1-2-3-4-/woo.html">343462^</a> et dolore magna aliqua.
+			Ut <a href="http://this.com">&amp;3640i6p1yi499</a> enim ad minim veniam, quis nostrud exercitation 16.06. to 18.06.2014 ullamco <a href="http://127.0.0.1">localhost</a>
+			laboris nisi ut aliquip ex <a href="http://www111.urwyeoweytwutreyytqytwetowteuiiu.com/?346236346326&amp;2134362574863.437">343462^</a> ea
+			commodo consequat. <a href="http://wordpress-core/1,2,3,4,5,6/-1-2-3-4-/woo.html">343462^</a> Duis aute irure dolor in reprehenderit in voluptate
+			velit esse <a href="http://wordpress-core.com:8080/">-3-4--321-64-4@#!$^$!@^@^</a> cillum dolore eu <A href="http://www.website.com:5000">http://www.website.com:5000</B> fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident,
+			sunt in culpa qui officia deserunt mollit <a href="http://wordpress-core/?346236346326&amp;2134362574863.437">)(*&^%$</a> anim id est laborum.';
+
+		$urls = wp_extract_urls( $blob );
+		$this->assertNotEmpty( $urls );
+		$this->assertIsArray( $urls );
+		$this->assertCount( 8, $urls );
+		$this->assertSame( array_slice( $original_urls, 0, 8 ), $urls );
+	}
+
+	/**
+	 * Tests for backward compatibility of `wp_extract_urls` to remove unused semicolons.
+	 *
+	 * @ticket 30580
+	 *
+	 * @covers ::wp_extract_urls
+	 */
+	public function test_wp_extract_urls_remove_semicolon() {
+		$expected = array(
+			'http://typo.com',
+			'http://example.org/?post_type=post&p=8',
+		);
+		$actual   = wp_extract_urls(
+			'
+				http://typo.com;
+				http://example.org/?post_type=;p;o;s;t;&amp;p=8;
+			'
+		);
+
+		$this->assertSame( $expected, $actual );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpGenerateUuid4.php b/tests/phpunit/tests/functions/wpGenerateUuid4.php
new file mode 100644
index 0000000000000..95569a020e6bb
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpGenerateUuid4.php
@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_generate_uuid4
+ */
+class Tests_Functions_WpGenerateUuid4 extends WP_UnitTestCase {
+
+	/**
+	 * Tests wp_generate_uuid4().
+	 *
+	 * @covers ::wp_generate_uuid4
+	 * @ticket 38164
+	 */
+	public function test_wp_generate_uuid4() {
+		$uuids = array();
+		for ( $i = 0; $i < 20; $i += 1 ) {
+			$uuid = wp_generate_uuid4();
+			$this->assertTrue( wp_is_uuid( $uuid, 4 ) );
+			$uuids[] = $uuid;
+		}
+
+		$unique_uuids = array_unique( $uuids );
+		$this->assertSame( $uuids, $unique_uuids );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpGetDefaultExtensionForMimeType.php b/tests/phpunit/tests/functions/wpGetDefaultExtensionForMimeType.php
new file mode 100644
index 0000000000000..88e2549ad27bd
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpGetDefaultExtensionForMimeType.php
@@ -0,0 +1,22 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_get_default_extension_for_mime_type
+ */
+class Tests_Functions_WpGetDefaultExtensionForMimeType extends WP_UnitTestCase {
+	/**
+	 * @ticket 53668
+	 */
+	public function test_wp_get_default_extension_for_mime_type() {
+		$this->assertSame( 'jpg', wp_get_default_extension_for_mime_type( 'image/jpeg' ), 'jpg not returned as default extension for "image/jpeg"' );
+		$this->assertNotEquals( 'jpeg', wp_get_default_extension_for_mime_type( 'image/jpeg' ), 'jpeg should not be returned as default extension for "image/jpeg"' );
+		$this->assertSame( 'png', wp_get_default_extension_for_mime_type( 'image/png' ), 'png not returned as default extension for "image/png"' );
+		$this->assertFalse( wp_get_default_extension_for_mime_type( 'wibble/wobble' ), 'false not returned for unrecognized mime type' );
+		$this->assertFalse( wp_get_default_extension_for_mime_type( '' ), 'false not returned when empty string as mime type supplied' );
+		$this->assertFalse( wp_get_default_extension_for_mime_type( '   ' ), 'false not returned when empty string as mime type supplied' );
+		$this->assertFalse( wp_get_default_extension_for_mime_type( 123 ), 'false not returned when int as mime type supplied' );
+		$this->assertFalse( wp_get_default_extension_for_mime_type( null ), 'false not returned when null as mime type supplied' );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpGetExtTypes.php b/tests/phpunit/tests/functions/wpGetExtTypes.php
new file mode 100644
index 0000000000000..fd0d2d1f41123
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpGetExtTypes.php
@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_get_ext_types
+ */
+class Tests_Functions_WpGetExtTypes extends WP_UnitTestCase {
+	/**
+	 * @ticket 35987
+	 */
+	public function test_wp_get_ext_types() {
+		$extensions = wp_get_ext_types();
+
+		$this->assertIsArray( $extensions );
+		$this->assertNotEmpty( $extensions );
+
+		add_filter( 'ext2type', '__return_empty_array' );
+		$extensions = wp_get_ext_types();
+		$this->assertSame( array(), $extensions );
+
+		remove_filter( 'ext2type', '__return_empty_array' );
+		$extensions = wp_get_ext_types();
+		$this->assertIsArray( $extensions );
+		$this->assertNotEmpty( $extensions );
+	}
+}
diff --git a/tests/phpunit/tests/http/wpGetHttpHeaders.php b/tests/phpunit/tests/functions/wpGetHttpHeaders.php
similarity index 100%
rename from tests/phpunit/tests/http/wpGetHttpHeaders.php
rename to tests/phpunit/tests/functions/wpGetHttpHeaders.php
diff --git a/tests/phpunit/tests/functions/wpGetImageMime.php b/tests/phpunit/tests/functions/wpGetImageMime.php
new file mode 100644
index 0000000000000..ab403f48e8bb4
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpGetImageMime.php
@@ -0,0 +1,109 @@
+<?php
+
+/**
+ * @group functions
+ * @group image
+ *
+ * @covers ::wp_get_image_mime
+ */
+class Tests_Functions_WpGetImageMime extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 40017
+	 * @dataProvider data_wp_get_image_mime
+	 */
+	public function test_wp_get_image_mime( $file, $expected ) {
+		if ( ! is_callable( 'exif_imagetype' ) && ! function_exists( 'getimagesize' ) ) {
+			$this->markTestSkipped( 'The exif PHP extension is not loaded.' );
+		}
+
+		if ( is_array( $expected ) ) {
+			$this->assertContains( wp_get_image_mime( $file ), $expected );
+		} else {
+			$this->assertSame( $expected, wp_get_image_mime( $file ) );
+		}
+	}
+
+	/**
+	 * Data provider for test_wp_get_image_mime().
+	 *
+	 * @return array[]
+	 */
+	public function data_wp_get_image_mime() {
+		$data = array(
+			// Standard JPEG.
+			array(
+				DIR_TESTDATA . '/images/test-image.jpg',
+				'image/jpeg',
+			),
+			// Standard GIF.
+			array(
+				DIR_TESTDATA . '/images/test-image.gif',
+				'image/gif',
+			),
+			// Standard PNG.
+			array(
+				DIR_TESTDATA . '/images/test-image.png',
+				'image/png',
+			),
+			// Image with wrong extension.
+			array(
+				DIR_TESTDATA . '/images/test-image-mime-jpg.png',
+				'image/jpeg',
+			),
+			// Animated WebP.
+			array(
+				DIR_TESTDATA . '/images/webp-animated.webp',
+				'image/webp',
+			),
+			// Lossless WebP.
+			array(
+				DIR_TESTDATA . '/images/webp-lossless.webp',
+				'image/webp',
+			),
+			// Lossy WebP.
+			array(
+				DIR_TESTDATA . '/images/webp-lossy.webp',
+				'image/webp',
+			),
+			// Transparent WebP.
+			array(
+				DIR_TESTDATA . '/images/webp-transparent.webp',
+				'image/webp',
+			),
+			// Not an image.
+			array(
+				DIR_TESTDATA . '/uploads/dashicons.woff',
+				false,
+			),
+			// Animated AVIF.
+			array(
+				DIR_TESTDATA . '/images/avif-animated.avif',
+				'image/avif',
+			),
+			// Lossless AVIF.
+			array(
+				DIR_TESTDATA . '/images/avif-lossless.avif',
+				'image/avif',
+			),
+			// Lossy AVIF.
+			array(
+				DIR_TESTDATA . '/images/avif-lossy.avif',
+				'image/avif',
+			),
+			// Transparent AVIF.
+			array(
+				DIR_TESTDATA . '/images/avif-transparent.avif',
+				'image/avif',
+			),
+			// HEIC.
+			array(
+				DIR_TESTDATA . '/images/test-image.heic',
+				// In PHP 8.5, it returns 'image/heif'. Before that, it returns 'image/heic'.
+				array( 'image/heic', 'image/heif' ),
+			),
+		);
+
+		return $data;
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpGetImageSize.php b/tests/phpunit/tests/functions/wpGetImageSize.php
new file mode 100644
index 0000000000000..eb48638df8f30
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpGetImageSize.php
@@ -0,0 +1,234 @@
+<?php
+
+/**
+ * @group functions
+ * @group media
+ *
+ * @covers ::wp_getimagesize
+ */
+class Tests_Functions_WpGetImageSize extends WP_UnitTestCase {
+	/**
+	 * @ticket 35725
+	 * @dataProvider data_wp_getimagesize
+	 */
+	public function test_wp_getimagesize( $file, $expected ) {
+		if ( ! is_callable( 'exif_imagetype' ) && ! function_exists( 'getimagesize' ) ) {
+			$this->markTestSkipped( 'The exif PHP extension is not loaded.' );
+		}
+
+		$result = wp_getimagesize( $file );
+
+		// The getimagesize() function varies in its response, so
+		// let's restrict comparison to expected keys only.
+		if ( is_array( $expected ) ) {
+			foreach ( $expected as $k => $v ) {
+				$this->assertArrayHasKey( $k, $result );
+				$this->assertSame( $expected[ $k ], $result[ $k ] );
+			}
+		} else {
+			$this->assertSame( $expected, $result );
+		}
+	}
+
+	/**
+	 * Data provider for test_wp_getimagesize().
+	 */
+	public function data_wp_getimagesize() {
+		$data = array(
+			// Standard JPEG.
+			array(
+				DIR_TESTDATA . '/images/test-image.jpg',
+				array(
+					50,
+					50,
+					IMAGETYPE_JPEG,
+					'width="50" height="50"',
+					'mime' => 'image/jpeg',
+				),
+			),
+			// Standard GIF.
+			array(
+				DIR_TESTDATA . '/images/test-image.gif',
+				array(
+					50,
+					50,
+					IMAGETYPE_GIF,
+					'width="50" height="50"',
+					'mime' => 'image/gif',
+				),
+			),
+			// Standard PNG.
+			array(
+				DIR_TESTDATA . '/images/test-image.png',
+				array(
+					50,
+					50,
+					IMAGETYPE_PNG,
+					'width="50" height="50"',
+					'mime' => 'image/png',
+				),
+			),
+			// Image with wrong extension.
+			array(
+				DIR_TESTDATA . '/images/test-image-mime-jpg.png',
+				array(
+					50,
+					50,
+					IMAGETYPE_JPEG,
+					'width="50" height="50"',
+					'mime' => 'image/jpeg',
+				),
+			),
+			// Animated WebP.
+			array(
+				DIR_TESTDATA . '/images/webp-animated.webp',
+				array(
+					100,
+					100,
+					IMAGETYPE_WEBP,
+					'width="100" height="100"',
+					'mime' => 'image/webp',
+				),
+			),
+			// Lossless WebP.
+			array(
+				DIR_TESTDATA . '/images/webp-lossless.webp',
+				array(
+					1200,
+					675,
+					IMAGETYPE_WEBP,
+					'width="1200" height="675"',
+					'mime' => 'image/webp',
+				),
+			),
+			// Lossy WebP.
+			array(
+				DIR_TESTDATA . '/images/webp-lossy.webp',
+				array(
+					1200,
+					675,
+					IMAGETYPE_WEBP,
+					'width="1200" height="675"',
+					'mime' => 'image/webp',
+				),
+			),
+			// Transparent WebP.
+			array(
+				DIR_TESTDATA . '/images/webp-transparent.webp',
+				array(
+					1200,
+					675,
+					IMAGETYPE_WEBP,
+					'width="1200" height="675"',
+					'mime' => 'image/webp',
+				),
+			),
+			// Not an image.
+			array(
+				DIR_TESTDATA . '/uploads/dashicons.woff',
+				false,
+			),
+			// Animated AVIF.
+			array(
+				DIR_TESTDATA . '/images/avif-animated.avif',
+				array(
+					150,
+					150,
+					IMAGETYPE_AVIF,
+					'width="150" height="150"',
+					'mime' => 'image/avif',
+				),
+			),
+			// Lossless AVIF.
+			array(
+				DIR_TESTDATA . '/images/avif-lossless.avif',
+				array(
+					400,
+					400,
+					IMAGETYPE_AVIF,
+					'width="400" height="400"',
+					'mime' => 'image/avif',
+				),
+			),
+			// Lossy AVIF.
+			array(
+				DIR_TESTDATA . '/images/avif-lossy.avif',
+				array(
+					400,
+					400,
+					IMAGETYPE_AVIF,
+					'width="400" height="400"',
+					'mime' => 'image/avif',
+				),
+			),
+			// Transparent AVIF.
+			array(
+				DIR_TESTDATA . '/images/avif-transparent.avif',
+				array(
+					128,
+					128,
+					IMAGETYPE_AVIF,
+					'width="128" height="128"',
+					'mime' => 'image/avif',
+				),
+			),
+			// Grid AVIF.
+			array(
+				DIR_TESTDATA . '/images/avif-alpha-grid2x1.avif',
+				array(
+					199,
+					200,
+					IMAGETYPE_AVIF,
+					'width="199" height="200"',
+					'mime' => 'image/avif',
+				),
+			),
+		);
+
+		return $data;
+	}
+
+	/**
+	 * Tests that wp_getimagesize() correctly handles HEIC image files.
+	 *
+	 * @ticket 53645
+	 */
+	public function test_wp_getimagesize_heic() {
+		if ( ! is_callable( 'exif_imagetype' ) && ! function_exists( 'getimagesize' ) ) {
+			$this->markTestSkipped( 'The exif PHP extension is not loaded.' );
+		}
+
+		$file = DIR_TESTDATA . '/images/test-image.heic';
+
+		$editor = wp_get_image_editor( $file );
+		if ( is_wp_error( $editor ) || ! $editor->supports_mime_type( 'image/heic' ) ) {
+			$this->markTestSkipped( 'No HEIC support in the editor engine on this system.' );
+		}
+
+		$expected = array(
+			1180,
+			1180,
+			IMAGETYPE_HEIF,
+			'width="1180" height="1180"',
+		);
+
+		// As of PHP 8.5.0, getimagesize() supports HEIF/HEIC files.
+		if ( PHP_VERSION_ID >= 80500 ) {
+			$expected = array_merge(
+				$expected,
+				array(
+					'bits'        => 8,
+					'channels'    => 3,
+					'mime'        => 'image/heif',
+					'width_unit'  => 'px',
+					'height_unit' => 'px',
+				)
+			);
+		} else {
+			$expected['mime'] = 'image/heic';
+		}
+
+		$result = wp_getimagesize( $file );
+		$this->assertSame( $expected, $result );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpGetMimeTypes.php b/tests/phpunit/tests/functions/wpGetMimeTypes.php
index 8bcd0aed8a9dc..7e69b35861f89 100644
--- a/tests/phpunit/tests/functions/wpGetMimeTypes.php
+++ b/tests/phpunit/tests/functions/wpGetMimeTypes.php
@@ -1,32 +1,40 @@
 <?php
 
 /**
- * Test wp_get_mime_types().
- *
  * @group functions
  *
  * @covers ::wp_get_mime_types
  */
-class Tests_Functions_wpGetMimeTypes extends WP_UnitTestCase {
-
+class Tests_Functions_WpGetMimeTypes extends WP_UnitTestCase {
 	/**
-	 * @ticket 47701
+	 * @ticket 21594
 	 */
-	public function test_all_mime_match() {
-		$mime_types_start = wp_get_mime_types();
+	public function test_wp_get_mime_types() {
+		$mimes = wp_get_mime_types();
 
-		$this->assertIsArray( $mime_types_start );
-		$this->assertNotEmpty( $mime_types_start );
+		$this->assertIsArray( $mimes );
+		$this->assertNotEmpty( $mimes );
 
 		add_filter( 'mime_types', '__return_empty_array' );
-		$mime_types_empty = wp_get_mime_types();
-		$this->assertSame( array(), $mime_types_empty );
+		$mimes = wp_get_mime_types();
+		$this->assertIsArray( $mimes );
+		$this->assertEmpty( $mimes );
 
 		remove_filter( 'mime_types', '__return_empty_array' );
-		$mime_types = wp_get_mime_types();
-		$this->assertIsArray( $mime_types );
-		$this->assertNotEmpty( $mime_types );
-		// Did it revert to the original after filter remove?
-		$this->assertSame( $mime_types_start, $mime_types );
+		$mimes = wp_get_mime_types();
+		$this->assertIsArray( $mimes );
+		$this->assertNotEmpty( $mimes );
+
+		// 'upload_mimes' should not affect wp_get_mime_types().
+		add_filter( 'upload_mimes', '__return_empty_array' );
+		$mimes = wp_get_mime_types();
+		$this->assertIsArray( $mimes );
+		$this->assertNotEmpty( $mimes );
+
+		remove_filter( 'upload_mimes', '__return_empty_array' );
+		$mimes2 = wp_get_mime_types();
+		$this->assertIsArray( $mimes2 );
+		$this->assertNotEmpty( $mimes2 );
+		$this->assertSame( $mimes2, $mimes );
 	}
 }
diff --git a/tests/phpunit/tests/functions/wpIsJsonMediaType.php b/tests/phpunit/tests/functions/wpIsJsonMediaType.php
new file mode 100644
index 0000000000000..aeda89167706c
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpIsJsonMediaType.php
@@ -0,0 +1,31 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_is_json_media_type
+ */
+class Tests_Functions_WpIsJsonMediaType extends WP_UnitTestCase {
+	/**
+	 * @ticket 49404
+	 * @dataProvider data_wp_is_json_media_type
+	 */
+	public function test_wp_is_json_media_type( $input, $expected ) {
+		$this->assertSame( $expected, wp_is_json_media_type( $input ) );
+	}
+
+
+	public function data_wp_is_json_media_type() {
+		return array(
+			array( 'application/ld+json', true ),
+			array( 'application/ld+json; profile="https://www.w3.org/ns/activitystreams"', true ),
+			array( 'application/activity+json', true ),
+			array( 'application/json+oembed', true ),
+			array( 'application/json', true ),
+			array( 'application/nojson', false ),
+			array( 'application/no.json', false ),
+			array( 'text/html, application/xhtml+xml, application/xml;q=0.9, image/webp, */*;q=0.8', false ),
+			array( 'application/activity+json, application/nojson', true ),
+		);
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpIsStream.php b/tests/phpunit/tests/functions/wpIsStream.php
new file mode 100644
index 0000000000000..9e8699bec0836
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpIsStream.php
@@ -0,0 +1,51 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_is_stream
+ */
+class Tests_Functions_WpIsStream extends WP_UnitTestCase {
+	/**
+	 * Test stream URL validation.
+	 *
+	 * @dataProvider data_wp_is_stream
+	 *
+	 * @param string $path     The resource path or URL.
+	 * @param bool   $expected Expected result.
+	 */
+	public function test_wp_is_stream( $path, $expected ) {
+		if ( ! extension_loaded( 'openssl' ) && false !== strpos( $path, 'https://' ) ) {
+			$this->markTestSkipped( 'The openssl PHP extension is not loaded.' );
+		}
+
+		$this->assertSame( $expected, wp_is_stream( $path ) );
+	}
+
+	/**
+	 * Data provider for stream URL validation.
+	 *
+	 * @return array {
+	 *     @type array ...$0 {
+	 *         @type string $0 The resource path or URL.
+	 *         @type bool   $1 Expected result.
+	 *     }
+	 * }
+	 */
+	public function data_wp_is_stream() {
+		return array(
+			// Legitimate stream examples.
+			array( 'http://example.com', true ),
+			array( 'https://example.com', true ),
+			array( 'ftp://example.com', true ),
+			array( 'file:///path/to/some/file', true ),
+			array( 'php://some/php/file.php', true ),
+
+			// Non-stream examples.
+			array( 'fakestream://foo/bar/baz', false ),
+			array( '../../some/relative/path', false ),
+			array( 'some/other/relative/path', false ),
+			array( '/leading/relative/path', false ),
+		);
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpIsUuid.php b/tests/phpunit/tests/functions/wpIsUuid.php
new file mode 100644
index 0000000000000..1dff89f161d11
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpIsUuid.php
@@ -0,0 +1,58 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_is_uuid
+ */
+class Tests_Functions_WpIsUuid extends WP_UnitTestCase {
+	/**
+	 * Tests wp_is_uuid().
+	 *
+	 * @covers ::wp_is_uuid
+	 * @ticket 39778
+	 */
+	public function test_wp_is_uuid() {
+		$uuids_v4 = array(
+			'27fe2421-780c-44c5-b39b-fff753092b55',
+			'b7c7713a-4ee9-45a1-87ed-944a90390fc7',
+			'fbedbe35-7bf5-49cc-a5ac-0343bd94360a',
+			'4c58e67e-123b-4290-a41c-5eeb6970fa3e',
+			'f54f5b78-e414-4637-84a9-a6cdc94a1beb',
+			'd1c533ac-abcf-44b6-9b0e-6477d2c91b09',
+			'7fcd683f-e5fd-454a-a8b9-ed15068830da',
+			'7962c750-e58c-470a-af0d-ec1eae453ff2',
+			'a59878ce-9a67-4493-8ca0-a756b52804b3',
+			'6faa519d-1e13-4415-bd6f-905ae3689d1d',
+		);
+
+		foreach ( $uuids_v4 as $uuid ) {
+			$this->assertTrue( wp_is_uuid( $uuid, 4 ) );
+		}
+
+		$uuids = array(
+			'00000000-0000-0000-0000-000000000000', // Nil.
+			'9e3a0460-d72d-11e4-a631-c8e0eb141dab', // Version 1.
+			'2c1d43b8-e6d7-376e-af7f-d4bde997cc3f', // Version 3.
+			'39888f87-fb62-5988-a425-b2ea63f5b81e', // Version 5.
+		);
+
+		foreach ( $uuids as $uuid ) {
+			$this->assertTrue( wp_is_uuid( $uuid ) );
+			$this->assertFalse( wp_is_uuid( $uuid, 4 ) );
+		}
+
+		$invalid_uuids = array(
+			'a19d5192-ea41-41e6-b006',
+			'this-is-not-valid',
+			1234,
+			true,
+			array(),
+		);
+
+		foreach ( $invalid_uuids as $invalid_uuid ) {
+			$this->assertFalse( wp_is_uuid( $invalid_uuid, 4 ) );
+			$this->assertFalse( wp_is_uuid( $invalid_uuid ) );
+		}
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpJsonEncode.php b/tests/phpunit/tests/functions/wpJsonEncode.php
new file mode 100644
index 0000000000000..8d91a212b07bc
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpJsonEncode.php
@@ -0,0 +1,96 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_json_encode
+ */
+class Tests_Functions_WpJsonEncode extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 28786
+	 */
+	public function test_wp_json_encode() {
+		$this->assertSame( wp_json_encode( 'a' ), '"a"' );
+	}
+
+	/**
+	 * @ticket 28786
+	 */
+	public function test_wp_json_encode_utf8() {
+		$this->assertSame( wp_json_encode( '这' ), '"\u8fd9"' );
+	}
+
+	/**
+	 * @ticket 28786
+	 * @requires function mb_detect_order
+	 */
+	public function test_wp_json_encode_non_utf8() {
+		$charsets     = mb_detect_order();
+		$old_charsets = $charsets;
+		if ( ! in_array( 'EUC-JP', $charsets, true ) ) {
+			$charsets[] = 'EUC-JP';
+			mb_detect_order( $charsets );
+		}
+
+		$eucjp = mb_convert_encoding( 'aあb', 'EUC-JP', 'UTF-8' );
+		$utf8  = mb_convert_encoding( $eucjp, 'UTF-8', 'EUC-JP' );
+
+		$this->assertSame( 'aあb', $utf8 );
+
+		$this->assertSame( '"a\u3042b"', wp_json_encode( $eucjp ) );
+
+		mb_detect_order( $old_charsets );
+	}
+
+	/**
+	 * @ticket 28786
+	 * @requires function mb_detect_order
+	 */
+	public function test_wp_json_encode_non_utf8_in_array() {
+		$charsets     = mb_detect_order();
+		$old_charsets = $charsets;
+		if ( ! in_array( 'EUC-JP', $charsets, true ) ) {
+			$charsets[] = 'EUC-JP';
+			mb_detect_order( $charsets );
+		}
+
+		$eucjp = mb_convert_encoding( 'aあb', 'EUC-JP', 'UTF-8' );
+		$utf8  = mb_convert_encoding( $eucjp, 'UTF-8', 'EUC-JP' );
+
+		$this->assertSame( 'aあb', $utf8 );
+
+		$this->assertSame( '["c","a\u3042b"]', wp_json_encode( array( 'c', $eucjp ) ) );
+
+		mb_detect_order( $old_charsets );
+	}
+
+	/**
+	 * @ticket 28786
+	 */
+	public function test_wp_json_encode_array() {
+		$this->assertSame( wp_json_encode( array( 'a' ) ), '["a"]' );
+	}
+
+	/**
+	 * @ticket 28786
+	 */
+	public function test_wp_json_encode_object() {
+		$object    = new stdClass();
+		$object->a = 'b';
+		$this->assertSame( wp_json_encode( $object ), '{"a":"b"}' );
+	}
+
+	/**
+	 * @ticket 28786
+	 */
+	public function test_wp_json_encode_depth() {
+		$data = array( array( array( 1, 2, 3 ) ) );
+		$json = wp_json_encode( $data, 0, 1 );
+		$this->assertFalse( $json );
+
+		$data = array( 'あ', array( array( 1, 2, 3 ) ) );
+		$json = wp_json_encode( $data, 0, 1 );
+		$this->assertFalse( $json );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpJsonFileDecode.php b/tests/phpunit/tests/functions/wpJsonFileDecode.php
new file mode 100644
index 0000000000000..ce265ed3fd557
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpJsonFileDecode.php
@@ -0,0 +1,33 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_json_file_decode
+ */
+class Tests_Functions_WpJsonFileDecode extends WP_UnitTestCase {
+	/**
+	 * @ticket 53238
+	 */
+	public function test_wp_json_file_decode() {
+		$result = wp_json_file_decode(
+			DIR_TESTDATA . '/blocks/notice/block.json'
+		);
+
+		$this->assertIsObject( $result );
+		$this->assertSame( 'tests/notice', $result->name );
+	}
+
+	/**
+	 * @ticket 53238
+	 */
+	public function test_wp_json_file_decode_associative_array() {
+		$result = wp_json_file_decode(
+			DIR_TESTDATA . '/blocks/notice/block.json',
+			array( 'associative' => true )
+		);
+
+		$this->assertIsArray( $result );
+		$this->assertSame( 'tests/notice', $result['name'] );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpNormalizePath.php b/tests/phpunit/tests/functions/wpNormalizePath.php
new file mode 100644
index 0000000000000..1b106f02e3531
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpNormalizePath.php
@@ -0,0 +1,102 @@
+<?php
+
+/**
+ * @ticket 65526
+ *
+ * @group functions
+ *
+ * @covers ::wp_normalize_path
+ */
+class Tests_Functions_WpNormalizePath extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 33265
+	 * @ticket 35996
+	 *
+	 * @dataProvider data_wp_normalize_path
+	 */
+	public function test_wp_normalize_path( $path, $expected ) {
+		$this->assertSame( $expected, wp_normalize_path( $path ) );
+	}
+
+	public function data_wp_normalize_path() {
+		return array(
+			// Windows paths.
+			array( 'C:\\www\\path\\', 'C:/www/path/' ),
+			array( 'C:\\www\\\\path\\', 'C:/www/path/' ),
+			array( 'c:/www/path', 'C:/www/path' ),
+			array( 'c:\\www\\path\\', 'C:/www/path/' ), // Uppercase drive letter.
+			array( 'c:\\\\www\\path\\', 'C:/www/path/' ),
+			array( '\\\\Domain\\DFSRoots\\share\\path\\', '//Domain/DFSRoots/share/path/' ),
+			array( '\\\\Server\\share\\path', '//Server/share/path' ),
+			array( '\\\\Server\\share', '//Server/share' ),
+
+			// Linux paths.
+			array( '/www/path/', '/www/path/' ),
+			array( '/www/path/////', '/www/path/' ),
+			array( '/www/path', '/www/path' ),
+
+			// PHP stream wrappers.
+			array( 'php://input', 'php://input' ),
+			array( 'http://example.com//path.ext', 'http://example.com/path.ext' ),
+			array( 'file://c:\\www\\path\\', 'file://C:/www/path/' ),
+
+			// Edge cases.
+			array( '', '' ), // Empty string should return empty string.
+			array( 123, '123' ), // Integer should be cast to string.
+		);
+	}
+
+	/**
+	 * Tests that wp_normalize_path() works with objects that have __toString().
+	 *
+	 * This is important because the function uses a static cache, and the input
+	 * must be cast to string before being used as an array key.
+	 *
+	 * @ticket 64538
+	 */
+	public function test_wp_normalize_path_with_stringable_object() {
+		$file_info = new SplFileInfo( '/var/www/html\\test' );
+
+		$this->assertSame( '/var/www/html/test', wp_normalize_path( $file_info ) );
+	}
+
+	/**
+	 * Tests that wp_normalize_path() returns consistent results on repeated calls.
+	 *
+	 * The function uses a static cache, so this verifies cache behavior.
+	 *
+	 * @ticket 64538
+	 */
+	public function test_wp_normalize_path_returns_consistent_results() {
+		$path = 'C:\\www\\path\\';
+
+		$first_call  = wp_normalize_path( $path );
+		$second_call = wp_normalize_path( $path );
+		$third_call  = wp_normalize_path( $path );
+
+		$this->assertSame( $first_call, $second_call, 'Second call should return same result as first.' );
+		$this->assertSame( $second_call, $third_call, 'Third call should return same result as second.' );
+		$this->assertSame( 'C:/www/path/', $first_call, 'Normalized path should match expected value.' );
+	}
+
+	/**
+	 * Tests that wp_normalize_path() static cache stores results.
+	 *
+	 * @ticket 64538
+	 */
+	public function test_wp_normalize_path_static_cache() {
+		$path     = '/var/www/cache-test\\subdir\\';
+		$expected = '/var/www/cache-test/subdir/';
+
+		$result = wp_normalize_path( $path );
+		$this->assertSame( $expected, $result );
+
+		$reflection  = new ReflectionFunction( 'wp_normalize_path' );
+		$static_vars = $reflection->getStaticVariables();
+
+		$this->assertArrayHasKey( 'cache', $static_vars, 'Static cache array should exist.' );
+		$this->assertArrayHasKey( $path, $static_vars['cache'], 'Cache should contain the normalized path.' );
+		$this->assertSame( $expected, $static_vars['cache'][ $path ], 'Cached value should match the expected normalized path.' );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpParseArgs.php b/tests/phpunit/tests/functions/wpParseArgs.php
new file mode 100644
index 0000000000000..1f29208c37c1a
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpParseArgs.php
@@ -0,0 +1,88 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_parse_args
+ */
+class Tests_Functions_WpParseArgs extends WP_UnitTestCase {
+	public function test_wp_parse_args_object() {
+		$x        = new MockClass();
+		$x->_baba = 5;
+		$x->yZ    = 'baba'; // phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
+		$x->a     = array( 5, 111, 'x' );
+		$this->assertSame(
+			array(
+				'_baba' => 5,
+				'yZ'    => 'baba',
+				'a'     => array( 5, 111, 'x' ),
+			),
+			wp_parse_args( $x )
+		);
+		$y = new MockClass();
+		$this->assertSame( array(), wp_parse_args( $y ) );
+	}
+
+	public function test_wp_parse_args_array() {
+		// Arrays.
+		$a = array();
+		$this->assertSame( array(), wp_parse_args( $a ) );
+		$b = array(
+			'_baba' => 5,
+			'yZ'    => 'baba',
+			'a'     => array( 5, 111, 'x' ),
+		);
+		$this->assertSame(
+			array(
+				'_baba' => 5,
+				'yZ'    => 'baba',
+				'a'     => array( 5, 111, 'x' ),
+			),
+			wp_parse_args( $b )
+		);
+	}
+
+	public function test_wp_parse_args_defaults() {
+		$x        = new MockClass();
+		$x->_baba = 5;
+		$x->yZ    = 'baba'; // phpcs:ignore WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase
+		$x->a     = array( 5, 111, 'x' );
+		$d        = array( 'pu' => 'bu' );
+		$this->assertSame(
+			array(
+				'pu'    => 'bu',
+				'_baba' => 5,
+				'yZ'    => 'baba',
+				'a'     => array( 5, 111, 'x' ),
+			),
+			wp_parse_args( $x, $d )
+		);
+		$e = array( '_baba' => 6 );
+		$this->assertSame(
+			array(
+				'_baba' => 5,
+				'yZ'    => 'baba',
+				'a'     => array( 5, 111, 'x' ),
+			),
+			wp_parse_args( $x, $e )
+		);
+	}
+
+	public function test_wp_parse_args_other() {
+		$b = true;
+		wp_parse_str( $b, $s );
+		$this->assertSame( $s, wp_parse_args( $b ) );
+		$q = 'x=5&_baba=dudu&';
+		wp_parse_str( $q, $ss );
+		$this->assertSame( $ss, wp_parse_args( $q ) );
+	}
+
+	/**
+	 * @ticket 30753
+	 */
+	public function test_wp_parse_args_boolean_strings() {
+		$args = wp_parse_args( 'foo=false&bar=true' );
+		$this->assertIsString( $args['foo'] );
+		$this->assertIsString( $args['bar'] );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpRaiseMemoryLimit.php b/tests/phpunit/tests/functions/wpRaiseMemoryLimit.php
new file mode 100644
index 0000000000000..4bb9dcc016e2c
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpRaiseMemoryLimit.php
@@ -0,0 +1,30 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_raise_memory_limit
+ */
+class Tests_Functions_WpRaiseMemoryLimit extends WP_UnitTestCase {
+	/**
+	 * Tests raising the memory limit.
+	 *
+	 * Unfortunately as the default for 'WP_MAX_MEMORY_LIMIT' in the
+	 * test suite is -1, we can not test the memory limit negotiations.
+	 *
+	 * @ticket 32075
+	 */
+	public function test_wp_raise_memory_limit() {
+		if ( -1 !== WP_MAX_MEMORY_LIMIT ) {
+			$this->markTestSkipped( 'WP_MAX_MEMORY_LIMIT should be set to -1.' );
+		}
+
+		$ini_limit_before = ini_get( 'memory_limit' );
+		$raised_limit     = wp_raise_memory_limit();
+		$ini_limit_after  = ini_get( 'memory_limit' );
+
+		$this->assertSame( $ini_limit_before, $ini_limit_after );
+		$this->assertFalse( $raised_limit );
+		$this->assertEquals( WP_MAX_MEMORY_LIMIT, $ini_limit_after );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpRecursiveKsort.php b/tests/phpunit/tests/functions/wpRecursiveKsort.php
new file mode 100644
index 0000000000000..278199dd70196
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpRecursiveKsort.php
@@ -0,0 +1,95 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_recursive_ksort
+ */
+class Tests_Functions_WpRecursiveKsort extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 55505
+	 * @covers ::wp_recursive_ksort
+	 */
+	public function test_wp_recursive_ksort() {
+		// Create an array to test.
+		$theme_json = array(
+			'version'  => 1,
+			'settings' => array(
+				'typography' => array(
+					'fontFamilies' => array(
+						'fontFamily' => 'DM Sans, sans-serif',
+						'slug'       => 'dm-sans',
+						'name'       => 'DM Sans',
+					),
+				),
+				'color'      => array(
+					'palette' => array(
+						array(
+							'slug'  => 'foreground',
+							'color' => '#242321',
+							'name'  => 'Foreground',
+						),
+						array(
+							'slug'  => 'background',
+							'color' => '#FCFBF8',
+							'name'  => 'Background',
+						),
+						array(
+							'slug'  => 'primary',
+							'color' => '#71706E',
+							'name'  => 'Primary',
+						),
+						array(
+							'slug'  => 'tertiary',
+							'color' => '#CFCFCF',
+							'name'  => 'Tertiary',
+						),
+					),
+				),
+			),
+		);
+
+		// Sort the array.
+		wp_recursive_ksort( $theme_json );
+
+		// Expected result.
+		$expected_theme_json = array(
+			'settings' => array(
+				'color'      => array(
+					'palette' => array(
+						array(
+							'color' => '#242321',
+							'name'  => 'Foreground',
+							'slug'  => 'foreground',
+						),
+						array(
+							'color' => '#FCFBF8',
+							'name'  => 'Background',
+							'slug'  => 'background',
+						),
+						array(
+							'color' => '#71706E',
+							'name'  => 'Primary',
+							'slug'  => 'primary',
+						),
+						array(
+							'color' => '#CFCFCF',
+							'name'  => 'Tertiary',
+							'slug'  => 'tertiary',
+						),
+					),
+				),
+				'typography' => array(
+					'fontFamilies' => array(
+						'fontFamily' => 'DM Sans, sans-serif',
+						'name'       => 'DM Sans',
+						'slug'       => 'dm-sans',
+					),
+				),
+			),
+			'version'  => 1,
+		);
+		$this->assertSameSetsWithIndex( $theme_json, $expected_theme_json );
+	}
+}
diff --git a/tests/phpunit/tests/date/wpTimezone.php b/tests/phpunit/tests/functions/wpTimezone.php
similarity index 90%
rename from tests/phpunit/tests/date/wpTimezone.php
rename to tests/phpunit/tests/functions/wpTimezone.php
index d4e7e7e220fdd..17e27e0fe4462 100644
--- a/tests/phpunit/tests/date/wpTimezone.php
+++ b/tests/phpunit/tests/functions/wpTimezone.php
@@ -4,7 +4,6 @@
  * @group date
  * @group datetime
  *
- * @covers ::wp_timezone_string
  * @covers ::wp_timezone
  */
 class Tests_Date_wpTimezone extends WP_UnitTestCase {
@@ -32,8 +31,6 @@ public function test_should_convert_gmt_offset( $gmt_offset, $tz_name ) {
 		delete_option( 'timezone_string' );
 		update_option( 'gmt_offset', $gmt_offset );
 
-		$this->assertSame( $tz_name, wp_timezone_string() );
-
 		$timezone = wp_timezone();
 
 		$this->assertSame( $tz_name, $timezone->getName() );
@@ -110,11 +107,9 @@ public function data_should_convert_gmt_offset() {
 	/**
 	 * @ticket 24730
 	 */
-	public function test_should_return_timezone_string() {
+	public function test_should_return_timezone_object() {
 		update_option( 'timezone_string', 'Europe/Helsinki' );
 
-		$this->assertSame( 'Europe/Helsinki', wp_timezone_string() );
-
 		$timezone = wp_timezone();
 
 		$this->assertSame( 'Europe/Helsinki', $timezone->getName() );
@@ -125,12 +120,10 @@ public function test_should_return_timezone_string() {
 	 *
 	 * @ticket 56468
 	 */
-	public function test_should_return_deprecated_timezone_string() {
+	public function test_should_return_deprecated_timezone_object() {
 		$tz_string = 'America/Buenos_Aires'; // This timezone was deprecated pre-PHP 5.6.
 		update_option( 'timezone_string', $tz_string );
 
-		$this->assertSame( $tz_string, wp_timezone_string() );
-
 		$timezone = wp_timezone();
 
 		$this->assertSame( $tz_string, $timezone->getName() );
diff --git a/tests/phpunit/tests/functions/wpTimezoneString.php b/tests/phpunit/tests/functions/wpTimezoneString.php
new file mode 100644
index 0000000000000..cfea6d9ffa5ff
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpTimezoneString.php
@@ -0,0 +1,125 @@
+<?php
+
+/**
+ * @group date
+ * @group datetime
+ *
+ * @covers ::wp_timezone_string
+ */
+class Tests_Date_wpTimezoneString extends WP_UnitTestCase {
+
+	/**
+	 * Cleans up.
+	 */
+	public function tear_down() {
+		// Reset changed options to their default value.
+		update_option( 'gmt_offset', 0 );
+		update_option( 'timezone_string', '' );
+
+		parent::tear_down();
+	}
+
+	/**
+	 * @ticket 24730
+	 *
+	 * @dataProvider data_should_convert_gmt_offset
+	 *
+	 * @param float  $gmt_offset Numeric offset from UTC.
+	 * @param string $tz_name    Expected timezone name.
+	 */
+	public function test_should_convert_gmt_offset( $gmt_offset, $tz_name ) {
+		delete_option( 'timezone_string' );
+		update_option( 'gmt_offset', $gmt_offset );
+
+		$this->assertSame( $tz_name, wp_timezone_string() );
+	}
+
+	/**
+	 * Data provider to test numeric offset conversion.
+	 *
+	 * @return array
+	 */
+	public function data_should_convert_gmt_offset() {
+		return array(
+			array( -12, '-12:00' ),
+			array( -11.5, '-11:30' ),
+			array( -11, '-11:00' ),
+			array( -10.5, '-10:30' ),
+			array( -10, '-10:00' ),
+			array( -9.5, '-09:30' ),
+			array( -9, '-09:00' ),
+			array( -8.5, '-08:30' ),
+			array( -8, '-08:00' ),
+			array( -7.5, '-07:30' ),
+			array( -7, '-07:00' ),
+			array( -6.5, '-06:30' ),
+			array( -6, '-06:00' ),
+			array( -5.5, '-05:30' ),
+			array( -5, '-05:00' ),
+			array( -4.5, '-04:30' ),
+			array( -4, '-04:00' ),
+			array( -3.5, '-03:30' ),
+			array( -3, '-03:00' ),
+			array( -2.5, '-02:30' ),
+			array( -2, '-02:00' ),
+			array( '-1.5', '-01:30' ),
+			array( -1.5, '-01:30' ),
+			array( -1, '-01:00' ),
+			array( -0.5, '-00:30' ),
+			array( 0, '+00:00' ),
+			array( '0', '+00:00' ),
+			array( 0.5, '+00:30' ),
+			array( 1, '+01:00' ),
+			array( 1.5, '+01:30' ),
+			array( '1.5', '+01:30' ),
+			array( 2, '+02:00' ),
+			array( 2.5, '+02:30' ),
+			array( 3, '+03:00' ),
+			array( 3.5, '+03:30' ),
+			array( 4, '+04:00' ),
+			array( 4.5, '+04:30' ),
+			array( 5, '+05:00' ),
+			array( 5.5, '+05:30' ),
+			array( 5.75, '+05:45' ),
+			array( 6, '+06:00' ),
+			array( 6.5, '+06:30' ),
+			array( 7, '+07:00' ),
+			array( 7.5, '+07:30' ),
+			array( 8, '+08:00' ),
+			array( 8.5, '+08:30' ),
+			array( 8.75, '+08:45' ),
+			array( 9, '+09:00' ),
+			array( 9.5, '+09:30' ),
+			array( 10, '+10:00' ),
+			array( 10.5, '+10:30' ),
+			array( 11, '+11:00' ),
+			array( 11.5, '+11:30' ),
+			array( 12, '+12:00' ),
+			array( 12.75, '+12:45' ),
+			array( 13, '+13:00' ),
+			array( 13.75, '+13:45' ),
+			array( 14, '+14:00' ),
+		);
+	}
+
+	/**
+	 * @ticket 24730
+	 */
+	public function test_should_return_timezone_string() {
+		update_option( 'timezone_string', 'Europe/Helsinki' );
+
+		$this->assertSame( 'Europe/Helsinki', wp_timezone_string() );
+	}
+
+	/**
+	 * Ensures that deprecated timezone strings are handled correctly.
+	 *
+	 * @ticket 56468
+	 */
+	public function test_should_return_deprecated_timezone_string() {
+		$tz_string = 'America/Buenos_Aires'; // This timezone was deprecated pre-PHP 5.6.
+		update_option( 'timezone_string', $tz_string );
+
+		$this->assertSame( $tz_string, wp_timezone_string() );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpUniqueFilename.php b/tests/phpunit/tests/functions/wpUniqueFilename.php
new file mode 100644
index 0000000000000..ed48f242ea805
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpUniqueFilename.php
@@ -0,0 +1,193 @@
+<?php
+
+/**
+ * @group functions
+ * @group upload
+ *
+ * @covers ::wp_unique_filename
+ */
+class Tests_Functions_WpUniqueFilename extends WP_UnitTestCase {
+
+	/**
+	 * @dataProvider data_wp_unique_filename
+	 *
+	 * @param string $filename Original filename.
+	 * @param string $expected Expected unique filename.
+	 * @param string $message  Assertion message.
+	 */
+	public function test_wp_unique_filename( $filename, $expected, $message ) {
+		$testdir = DIR_TESTDATA . '/images/';
+
+		$this->assertSame( $expected, wp_unique_filename( $testdir, $filename ), $message );
+	}
+
+	/**
+	 * Data provider for test_wp_unique_filename.
+	 *
+	 * @return array[]
+	 */
+	public function data_wp_unique_filename() {
+		return array(
+			'non-existing file'                     => array(
+				'filename' => 'abcdefg.png',
+				'expected' => 'abcdefg.png',
+				'message'  => 'Test non-existing file, file name should be unchanged.',
+			),
+			'file already exists'                   => array(
+				'filename' => 'test-image.png',
+				'expected' => 'test-image-1.png',
+				'message'  => 'File name not unique, number not appended.',
+			),
+			'uppercase extension'                   => array(
+				'filename' => 'test-image.PNG',
+				'expected' => 'test-image-1.png',
+				'message'  => 'File name with uppercase extension not unique, number not appended.',
+			),
+			'already added number'                  => array(
+				'filename' => 'test-image-2.gif',
+				'expected' => 'test-image-2-1.gif',
+				'message'  => 'File name not unique, number not appended correctly.',
+			),
+			'special chars'                         => array(
+				'filename' => 'testtést-imagé.png',
+				'expected' => 'testtest-image.png',
+				'message'  => 'Filename with special chars failed',
+			),
+			'special chars with potential conflict' => array(
+				'filename' => 'tést-imagé.png',
+				'expected' => 'test-image-1.png',
+				'message'  => 'Filename with special chars failed',
+			),
+			'single quotes in name'                 => array(
+				'filename' => "abcdefg'h.png",
+				'expected' => 'abcdefgh.png',
+				'message'  => 'File with quote failed',
+			),
+			'double quotes in name'                 => array(
+				'filename' => 'abcdefg"h.png',
+				'expected' => 'abcdefgh.png',
+				'message'  => 'File with quote failed',
+			),
+			'crazy name'                            => array(
+				'filename' => '12%af34567890#~!@#$..%^&*()|_+qwerty  fgh`jkl zx<>?:"{}[]="\'/?.png',
+				'expected' => '12af34567890@.^_qwerty-fghjkl-zx.png',
+				'message'  => 'Failed crazy file name',
+			),
+			'single slash'                          => array(
+				'filename' => 'abcde\fg.png',
+				'expected' => 'abcdefg.png',
+				'message'  => 'Slash not removed',
+			),
+			'double slash'                          => array(
+				'filename' => 'abcde\\fg.png',
+				'expected' => 'abcdefg.png',
+				'message'  => 'Double slashed not removed',
+			),
+			'triple slash'                          => array(
+				'filename' => 'abcde\\\fg.png',
+				'expected' => 'abcdefg.png',
+				'message'  => 'Triple slashed not removed',
+			),
+		);
+	}
+
+	/**
+	 * @ticket 42437
+	 */
+	public function test_unique_filename_with_dimension_like_filename() {
+		$testdir = DIR_TESTDATA . '/images/';
+
+		add_filter( 'upload_dir', array( $this, 'upload_dir_patch_basedir' ) );
+
+		// Test collision with "dimension-like" original filename.
+		$this->assertSame( 'one-blue-pixel-100x100-1.png', wp_unique_filename( $testdir, 'one-blue-pixel-100x100.png' ) );
+		// Test collision with existing sub-size filename.
+		// Existing files: one-blue-pixel-100x100.png, one-blue-pixel-1-100x100.png.
+		$this->assertSame( 'one-blue-pixel-2.png', wp_unique_filename( $testdir, 'one-blue-pixel.png' ) );
+		// Same as above with upper case extension.
+		$this->assertSame( 'one-blue-pixel-2.png', wp_unique_filename( $testdir, 'one-blue-pixel.PNG' ) );
+
+		remove_filter( 'upload_dir', array( $this, 'upload_dir_patch_basedir' ) );
+	}
+
+	// Callback to patch "basedir" when used in `wp_unique_filename()`.
+	public function upload_dir_patch_basedir( $upload_dir ) {
+		$upload_dir['basedir'] = DIR_TESTDATA . '/images/';
+		return $upload_dir;
+	}
+
+	/**
+	 * @ticket 53668
+	 */
+	public function test_wp_unique_filename_with_additional_image_extension() {
+		$testdir = DIR_TESTDATA . '/images/';
+
+		add_filter( 'upload_dir', array( $this, 'upload_dir_patch_basedir' ) );
+
+		// Set conversions for uploaded images.
+		add_filter( 'image_editor_output_format', array( $this, 'image_editor_output_format_handler' ) );
+
+		// Ensure the test images exist.
+		$this->assertFileExists( $testdir . 'test-image-1-100x100.jpg', 'test-image-1-100x100.jpg does not exist' );
+		$this->assertFileExists( $testdir . 'test-image-2.gif', 'test-image-2.gif does not exist' );
+		$this->assertFileExists( $testdir . 'test-image-3.jpg', 'test-image-3.jpg does not exist' );
+		$this->assertFileExists( $testdir . 'test-image-4.png', 'test-image-4.png does not exist' );
+
+		// Standard test: file does not exist and there are no possible intersections with other files.
+		$this->assertSame(
+			'abcdef.png',
+			wp_unique_filename( $testdir, 'abcdef.png' ),
+			'The abcdef.png, abcdef.gif, and abcdef.jpg images do not exist. The file name should not be changed.'
+		);
+
+		// Actual clash recognized.
+		$this->assertSame(
+			'canola-1.jpg',
+			wp_unique_filename( $testdir, 'canola.jpg' ),
+			'The canola.jpg image exists. The file name should be unique.'
+		);
+
+		// Same name with different uppercase extension and the image will be converted.
+		$this->assertSame(
+			'canola-1.png',
+			wp_unique_filename( $testdir, 'canola.PNG' ),
+			'The canola.jpg image exists. Uploading canola.PNG that will be converted to canola.jpg should produce unique file name.'
+		);
+
+		// Actual clash with several images with different extensions.
+		$this->assertSame(
+			'test-image-5.png',
+			wp_unique_filename( $testdir, 'test-image.png' ),
+			'The test-image.png, test-image-1-100x100.jpg, test-image-2.gif, test-image-3.jpg, and test-image-4.png images exist.' .
+			'All of them may clash when creating sub-sizes or regenerating thumbnails in the future. The filename should be unique.'
+		);
+
+		// Possible clash with regenerated thumbnails in the future.
+		$this->assertSame(
+			'codeispoetry-1.jpg',
+			wp_unique_filename( $testdir, 'codeispoetry.jpg' ),
+			'The codeispoetry.png image exists. When regenerating thumbnails for it they will be converted to JPG.' .
+			'The name of the newly uploaded codeispoetry.jpg should be made unique.'
+		);
+
+		remove_filter( 'image_editor_output_format', array( $this, 'image_editor_output_format_handler' ) );
+		remove_filter( 'upload_dir', array( $this, 'upload_dir_patch_basedir' ) );
+	}
+
+	/**
+	 * Changes the output format when editing images. When uploading a PNG file
+	 * it will be converted to JPEG, GIF to JPEG, and PICT to BMP
+	 * (if the image editor in PHP supports it).
+	 *
+	 * @param array $formats
+	 *
+	 * @return array
+	 */
+	public function image_editor_output_format_handler( $formats ) {
+		$formats['image/png'] = 'image/jpeg';
+		$formats['image/gif'] = 'image/jpeg';
+		$formats['image/pct'] = 'image/bmp';
+
+		return $formats;
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpUniqueId.php b/tests/phpunit/tests/functions/wpUniqueId.php
new file mode 100644
index 0000000000000..931ea82b136f3
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpUniqueId.php
@@ -0,0 +1,36 @@
+<?php
+
+/**
+ * @group functions
+ *
+ * @covers ::wp_unique_id
+ */
+class Tests_Functions_WpUniqueId extends WP_UnitTestCase {
+	/**
+	 * Tests wp_unique_id().
+	 *
+	 * @covers ::wp_unique_id
+	 * @ticket 44883
+	 */
+	public function test_wp_unique_id() {
+
+		// Test without prefix.
+		$ids = array();
+		for ( $i = 0; $i < 20; $i += 1 ) {
+			$id = wp_unique_id();
+			$this->assertIsString( $id );
+			$this->assertIsNumeric( $id );
+			$ids[] = $id;
+		}
+		$this->assertSame( $ids, array_unique( $ids ) );
+
+		// Test with prefix.
+		$ids = array();
+		for ( $i = 0; $i < 20; $i += 1 ) {
+			$id = wp_unique_id( 'foo-' );
+			$this->assertMatchesRegularExpression( '/^foo-\d+$/', $id );
+			$ids[] = $id;
+		}
+		$this->assertSame( $ids, array_unique( $ids ) );
+	}
+}
diff --git a/tests/phpunit/tests/functions/wpUploadDir.php b/tests/phpunit/tests/functions/wpUploadDir.php
new file mode 100644
index 0000000000000..31a2f647ef4ed
--- /dev/null
+++ b/tests/phpunit/tests/functions/wpUploadDir.php
@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * @ticket 65526
+ *
+ * @group functions
+ * @group upload
+ *
+ * @covers ::wp_upload_dir
+ */
+class Tests_Functions_WpUploadDir extends WP_UnitTestCase {
+
+	public function set_up() {
+		parent::set_up();
+		$this->reset_options();
+	}
+
+	private function reset_options() {
+		// System defaults.
+		update_option( 'upload_path', 'wp-content/uploads' );
+		update_option( 'upload_url_path', '' );
+		update_option( 'uploads_use_yearmonth_folders', 1 );
+	}
+
+	/**
+	 * @covers ::wp_upload_dir
+	 */
+	public function test_upload_dir_default() {
+		// wp_upload_dir() with default parameters.
+		$info   = wp_upload_dir();
+		$subdir = date_format( date_create( 'now' ), '/Y/m' );
+
+		$this->assertSame( get_option( 'siteurl' ) . '/wp-content/uploads' . $subdir, $info['url'] );
+		$this->assertSame( ABSPATH . 'wp-content/uploads' . $subdir, $info['path'] );
+		$this->assertSame( $subdir, $info['subdir'] );
+		$this->assertFalse( $info['error'] );
+	}
+}
diff --git a/tests/phpunit/tests/upload.php b/tests/phpunit/tests/functions/wpUploadDirInternal.php
similarity index 86%
rename from tests/phpunit/tests/upload.php
rename to tests/phpunit/tests/functions/wpUploadDirInternal.php
index 46fcea7099097..822fcd580891b 100644
--- a/tests/phpunit/tests/upload.php
+++ b/tests/phpunit/tests/functions/wpUploadDirInternal.php
@@ -1,11 +1,14 @@
 <?php
+
 /**
+ * @ticket 65526
+ *
+ * @group functions
  * @group upload
- * @group media
+ *
+ * @covers ::_wp_upload_dir
  */
-class Tests_Upload extends WP_UnitTestCase {
-
-	public $siteurl;
+class Tests_Functions_WpUploadDirInternal extends WP_UnitTestCase {
 
 	public function set_up() {
 		parent::set_up();
@@ -19,17 +22,6 @@ private function reset_options() {
 		update_option( 'uploads_use_yearmonth_folders', 1 );
 	}
 
-	public function test_upload_dir_default() {
-		// wp_upload_dir() with default parameters.
-		$info   = wp_upload_dir();
-		$subdir = date_format( date_create( 'now' ), '/Y/m' );
-
-		$this->assertSame( get_option( 'siteurl' ) . '/wp-content/uploads' . $subdir, $info['url'] );
-		$this->assertSame( ABSPATH . 'wp-content/uploads' . $subdir, $info['path'] );
-		$this->assertSame( $subdir, $info['subdir'] );
-		$this->assertFalse( $info['error'] );
-	}
-
 	public function test_upload_dir_relative() {
 		// wp_upload_dir() with a relative upload path that is not 'wp-content/uploads'.
 		update_option( 'upload_path', 'foo/bar' );