test(win32): build the env-fault verify script for the host shell (#292)

[dracic]

Closes #292

Problem

test_fix_phase_session_env_fault_escalates put a POSIX check.sh into a VerifyPolicy command tuple. Verify commands run through the host shell, so on Windows cmd hands that path to ShellExecute — two failure modes, neither of which the test can see:

• no .sh association (stock Windows): the interactive "How do you want to open this file?" picker pops mid-run and steals focus.
• .sh associated (e.g. Git for Windows): the associated app launches and the command returns success without the script ever running — a silent false pass.

Either way the test passes, because the fault it asserts comes from an injected SessionResult(env_fault=True), so CI stayed green and only local full-suite runs saw the dialog.

Fix

Two commits, both test-only.

1. tests/test_engine.py — write check.cmd on win32, check.sh elsewhere; the POSIX branch is unchanged.

A win32 skip was rejected: the subject (#194 — a fix session that lost its API connection escalates instead of burning dev budget) is not POSIX-specific, unlike the three sibling tests, which skip on win32 because they depend on sh rc 126/127. Skipping would drop real Windows coverage of the escalation path.

Two details in the win32 branch:

• @exit /b 0, not @exit 0 — a bare exit in a batch file terminates the invoking cmd, not just the script.
• "\n", not "\r\n" — Path.write_text uses newline=None and already translates to CRLF on Windows; the explicit \r lands on disk as \r\r\n (reproduced).

2. tests/conftest.py — write_script_launcher had that identical redundant CR in its win32 launcher, so it gets the same correction. Harmless for a one-line launcher today, but the same defect, and fixing one site while leaving the shared helper broken would be symptom patching.

Verification

• Windows 11: pytest tests/test_engine.py → 194 passed, 3 skipped, no dialog
• Windows 11: pytest tests/test_engine_plugin.py tests/test_opencode_http.py (the write_script_launcher callers) → 112 passed, 4 skipped
• Linux: pytest tests/test_engine.py -k env_fault → 6 passed, 0 skipped
• ruff check / ruff format --check clean; tests/ is outside pyright's include

Scope

The three other inline .sh verify sites (_self_disarming_script and test_fix_phase_env_fault_escalates_instead_of_looping) are already @pytest.mark.skipif(sys.platform == "win32"), so this was the only unguarded one.

Follow-up: #302

One finding from this review is deliberately out of scope and filed as its own issue: ENV_FAULT_RCS = frozenset({126, 127}) never matches on Windows — cmd reports a missing or non-executable verify tool as 9009/1, so the charged-attempt behavior #126 exists to prevent still happens on win32, and the three skips above hide it. Reclassifying rc 1 carries a real false-positive risk (under cmd it is also the ordinary "tests failed" code), so it needs its own decision rather than riding a test-only fix.

[coderabbitai]

Walkthrough

The env-fault escalation test now creates check.cmd on Windows and an executable check.sh elsewhere, ensuring verify commands use a host-compatible script.

Changes

Test platform compatibility

Layer / File(s)	Summary
Platform-specific verify script setup tests/test_engine.py	The test generates a Windows batch script with exit /b 0, while non-Windows platforms continue using an executable shell script.

Estimated code review effort: 1 (Trivial) | ~3 minutes

Suggested reviewers: pbean

Poem

A bunny hops where scripts run,
check.cmd greets the Windows sun.
Bash still burrows, neat and bright,
No dialog interrupts the night.
Tests leap onward—what a sight!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The test now uses check.cmd on Windows and check.sh elsewhere, preserving Windows coverage as requested in #292.
Out of Scope Changes check	✅ Passed	The changes stay confined to the env-fault test and directly support the linked Windows script fix.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the Windows-host-shell test fix for the env-fault verify script.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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