tests: better printout on failure

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

test/utils.py

@@ -35,6 +35,24 @@
 }.get(detect_ci_provider(), True)
 
 
+def _subprocess_run(command: list[str], **kwargs: Any) -> None:
+    result = subprocess.run(
+        command,
+        capture_output=True,
+        check=False,
+        text=True,
+        **kwargs,
+    )
+    if result.returncode != 0:
+        msg = (
+            f"Subprocess failed with exit code {result.returncode}\n"
+            f"Command: {' '.join(command)}\n"
+            f"--- stdout ---\n{result.stdout}\n"
+            f"--- stderr ---\n{result.stderr}"
+        )
+        raise AssertionError(msg)
+
+
 def get_platform() -> str:
     """Return the current platform as determined by CIBW_PLATFORM or sys.platform."""
     platform = os.environ.get("CIBW_PLATFORM", "")
@@ -137,7 +155,7 @@ def cibuildwheel_run(
         env["CIBW_BUILD"] = "cp{}{}-*".format(*SINGLE_PYTHON_VERSION)
 
     with TemporaryDirectory() as tmp_output_dir:
-        subprocess.run(
+        _subprocess_run(
             [
                 sys.executable,
                 "-m",
@@ -149,7 +167,6 @@ def cibuildwheel_run(
             ],
             env=env,
             cwd=project_path,
-            check=True,
         )
         wheels = sorted(p.name for p in (output_dir or Path(tmp_output_dir)).iterdir())
     return wheels