Fix Windows check-build failure by broadening OSTYPE detection in test.sh

[Copilot]

The check-build GitHub Actions job on windows-latest with Python 3.12 failed because test.sh did not initialize CMD on Windows Git Bash. The script matched OSTYPE only when exactly msys, while runners report values like msys_nt-*.

• Root cause

  • Windows branch in test.sh used an exact match:
    • [[ "$OSTYPE" == "msys" ]]
  • On Actions, this condition does not match, so CMD remains unset under set -u.

• Change

  • Updated Windows OS detection to prefix match:
    • [[ "$OSTYPE" == "msys"* ]]
  • This ensures the Windows code path consistently sets PYTHON/CMD across Git Bash variants.

• Patch excerpt

  -elif [[ "$OSTYPE" == "msys" ]]; then
  +elif [[ "$OSTYPE" == "msys"* ]]; then
     PYTHON="python"
     CMD="$PYTHON -m sacrebleu"

[mjpost]

Ah, I see, the previous version didn't match "msys" and there is no default case.

[martinpopel]

@copilot The tests are still failing. Let's set the default CMD and PYTHON and override it only for "$OSTYPE" == "darwin"*:

PYTHON="python"
CMD="$PYTHON -m sacrebleu"
if [[ "$OSTYPE" == "darwin"* ]]; then
  # OS X ships python -> python2 by default, be explicit
  PYTHON=python3
  CMD="$PYTHON -m sacrebleu"
fi

[Copilot]

@copilot The tests are still failing. Let's set the default CMD and PYTHON and override it only for "$OSTYPE" == "darwin"*:

PYTHON="python"

...

Implemented in commit f411782.
test.sh now sets default PYTHON/CMD first and overrides only for darwin*.