test(frontend): extend ComputingUnitSelectionComponent coverage with resource getters

[mengw15]

What changes were proposed in this PR?

Extends the existing ComputingUnitSelectionComponent spec
(frontend/src/app/workspace/component/power-button/, codecov ~59%) to cover the
previously-untested resource-display getters and a few small handlers. Follows
frontend/TESTING.md and reuses the existing makeComputingUnit fixture.

Adds 13 tests:

• resource accessors — getCurrentComputingUnit{Cpu,Memory}Usage,
  getCurrentComputingUnit{Cpu,Memory,Gpu}Limit, getCurrentComputingUnitJvmMemorySize,
  getCurrentSharedMemorySize: read the selected unit's raw values, and return
  "NaN" for every accessor when nothing is selected.
• derived getters — getCpuLimit/getMemoryLimit (numbers), getGpuLimit/
  getJvmMemorySize/getSharedMemorySize, getCpuLimitUnit/getMemoryLimitUnit/
  getCpuUnit/getMemoryUnit; getCpuValue/getMemoryValue/getCpuPercentage/
  getMemoryPercentage return 0 when metrics are unavailable; getCpuStatus/
  getMemoryStatus map to "success"; getBadgeColor and getUnitStatusTooltip
  map status → color/tooltip.
• misc handlers — trackByCuid/trackByIndex identity, cancelEditingUnitName
  state reset, openComputingUnitMetadataModal opens the metadata modal with the
  unit as nzData, and scrollToBottomOfPipModal scrolls the deferred pip-log
  element (and is a safe no-op when it is absent).

No production code was changed.

Any related issues, documentation, discussions?

Closes #6551

How was this PR tested?

Extended Vitest spec, run locally in frontend/ (whole file green, run 4× to
confirm determinism; failure path verified by breaking an assertion). To stay
deterministic, scrollToBottomOfPipModal is driven with fake timers and a
stubbed document.getElementById (a plain stand-in object, restored after each
test) rather than relying on jsdom layout.

ng test --watch=false --include src/app/workspace/component/power-button/computing-unit-selection.component.spec.ts
# Test Files 1 passed (1) / Tests 100 passed (100)
eslint <spec>      # clean
prettier --check   # clean

Was this PR authored or co-authored using generative AI tooling?

Generated-by: Claude Code (Opus 4.8 [1M context])

[github-actions]

Automated Reviewer Suggestions

Based on the git blame history of the changed files, we recommend the following reviewers:

• Contributors with relevant context: @aglinxinyuan
  You can notify them by mentioning @aglinxinyuan in a comment.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.58%. Comparing base (80c45be) to head (ff3d8e1).

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6555      +/-   ##
============================================
+ Coverage     72.54%   72.58%   +0.04%     
  Complexity     3436     3436              
============================================
  Files          1145     1145              
  Lines         45129    45129              
  Branches       4975     4975              
============================================
+ Hits          32738    32757      +19     
+ Misses        10709    10686      -23     
- Partials       1682     1686       +4     

Flag	Coverage Δ		*Carryforward flag
access-control-service	70.00% <ø> (ø)		Carriedforward from 80c45be
agent-service	76.76% <ø> (ø)		Carriedforward from 80c45be
amber	66.81% <ø> (ø)		Carriedforward from 80c45be
computing-unit-managing-service	17.72% <ø> (ø)		Carriedforward from 80c45be
config-service	66.66% <ø> (ø)		Carriedforward from 80c45be
file-service	66.80% <ø> (ø)		Carriedforward from 80c45be
frontend	73.91% <ø> (+0.10%)	⬆️
notebook-migration-service	78.94% <ø> (ø)		Carriedforward from 80c45be
pyamber	91.79% <ø> (ø)		Carriedforward from 80c45be
workflow-compiling-service	55.14% <ø> (ø)		Carriedforward from 80c45be

*This pull request uses carry forward flags. Click here to find out more.

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[Copilot]

Pull request overview

This PR extends the existing frontend unit test coverage for ComputingUnitSelectionComponent by adding deterministic tests for previously-untested resource-display accessors/getters and a few small UI helper/handler methods. It aligns with the linked issue’s request to cover the “pure getter” surface area without changing production code.

Changes:

• Added unit tests for getCurrentComputingUnit* resource accessors, derived display getters (limits/units/values/percentages/status), and status mapping helpers.
• Added tests for trackBy*, cancelEditingUnitName, openComputingUnitMetadataModal, and scrollToBottomOfPipModal (including an absent-element no-op case).
• Imported ComputingUnitMetadataComponent for modal expectation matching in the new tests.

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[aglinxinyuan]

LGTM!