@@ -2,15 +2,39 @@
 
 from __future__ import annotations
 
+import os
 import shutil
 import subprocess
+import sys
 from pathlib import Path
 
 import pytest
 import yaml
 
 
-@pytest.mark.skipif(shutil.which("bash") is None, reason="CI invokes pytest with bash")
+def _bash() -> str | None:
+    """The bash the workflow's ``shell: bash`` runs, never the WSL launcher.
+
+    On a Windows runner ``bash`` on PATH can resolve to System32's WSL stub,
+    which exits 1 ("no installed distributions") without running anything,
+    so every case but exit status 1 failed. GitHub's ``shell: bash`` is Git
+    Bash.
+    """
+    if sys.platform != "win32":
+        return shutil.which("bash")
+    windir = os.environ.get("SystemRoot", r"C:\Windows").lower()
+    for folder in os.environ.get("PATH", "").split(os.pathsep):
+        found = shutil.which("bash", path=folder) if folder else None
+        if found and not (found.lower().startswith(windir) or "windowsapps" in found.lower()):
+            return found
+    default = Path(os.environ.get("ProgramFiles", r"C:\Program Files")) / "Git" / "bin" / "bash.exe"
+    return str(default) if default.is_file() else None
+
+
+BASH = _bash()
+
+
+@pytest.mark.skipif(BASH is None, reason="CI invokes pytest with bash")
 @pytest.mark.parametrize("exit_status", [0, 1, 2, 3, 4, 5, 130])
 def test_windows_ci_preserves_pytest_exit_status(tmp_path, exit_status):
     workflow_path = Path(__file__).resolve().parents[2] / ".github" / "workflows" / "ci.yml"
@@ -22,7 +46,7 @@ def test_windows_ci_preserves_pytest_exit_status(tmp_path, exit_status):
     fake_pytest = f"pytest() {{ printf '1 passed\\n'; return {exit_status}; }}\n"
 
     result = subprocess.run(
-        ["bash", "--noprofile", "--norc", "-e", "-o", "pipefail", "-c", fake_pytest + step["run"]],
+        [BASH, "--noprofile", "--norc", "-e", "-o", "pipefail", "-c", fake_pytest + step["run"]],
         cwd=tmp_path,
         capture_output=True,
         text=True,