test pack

[thedavidmeister]

Tighten the underflow test: make it pure and target the threshold precisely.

Mark the test pure (no state read/write).
Bound signedCoefficient to ≥1 to avoid discards.
Pin exponent to a value ≤ int32.min − 77 to deterministically exercise the lossy‑zero path.

Apply this diff:

• function testPackNegativeExponentLossyZero(int256 signedCoefficient, int256 exponent) external view {

•    exponent = bound(exponent, type(int256).min, int256(type(int32).min) - 77);
  

•    vm.assume(signedCoefficient != 0);
  

• function testPackNegativeExponentLossyZero(int256 signedCoefficient, int256 exponent) external pure {

•    signedCoefficient = bound(signedCoefficient, 1, type(int256).max);
  

•    exponent = bound(exponent, int256(type(int32).min) - 77, int256(type(int32).min) - 77);
     (Float float, bool lossless) = this.packLossyExternal(signedCoefficient, exponent);
     assertFalse(lossless, "lossless");
     assertEq(Float.unwrap(float), Float.unwrap(LibDecimalFloat.FLOAT_ZERO), "float");
  

  }

Consider adding a sibling test for the “within 1..76” underflow window to assert non‑zero, lossy pack clamped at int32.min.