fix: a step that could not run says so

tests/test_refresh_failures.py

@@ -0,0 +1,67 @@
+"""A step that could not do its job says so with its exit code.
+
+validate_pr --changed answered "No changed BIOS files detected" and exited
+0 when git itself had failed (no origin, or no repository), and
+check_buildbot_system --update exited 0 after a refresh it launched had
+failed, the cache left at the old version.
+"""
+
+from __future__ import annotations
+
+import subprocess
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+from unittest import mock
+
+REPO_ROOT = Path(__file__).resolve().parent.parent
+sys.path.insert(0, str(REPO_ROOT / "scripts"))
+
+import check_buildbot_system  # noqa: E402
+
+
+class GitThatCannotAnswer(unittest.TestCase):
+    def test_outside_a_repository_is_an_error_not_an_empty_change(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            proc = subprocess.run(
+                [sys.executable, str(REPO_ROOT / "scripts" / "validate_pr.py"), "--changed"],
+                cwd=tmp, capture_output=True, text=True, timeout=60, check=False,
+            )
+        self.assertEqual(proc.returncode, 2, proc.stdout + proc.stderr)
+        self.assertNotIn("No changed BIOS files detected", proc.stdout)
+
+    def test_a_clone_without_origin_reads_the_index_and_says_so(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            subprocess.run(["git", "init", "-q", tmp], check=True)
+            Path(tmp, "bios").mkdir()
+            Path(tmp, "bios", "x.bin").write_bytes(b"x")
+            subprocess.run(["git", "-C", tmp, "add", "bios/x.bin"], check=True)
+            proc = subprocess.run(
+                [sys.executable, "-c", (
+                    f"import sys; sys.path.insert(0, {str(REPO_ROOT / 'scripts')!r}); "
+                    "import validate_pr; print(validate_pr.get_changed_files())"
+                )],
+                cwd=tmp, capture_output=True, text=True, timeout=60, check=False,
+            )
+        self.assertEqual(proc.returncode, 0, proc.stderr)
+        self.assertIn("bios/x.bin", proc.stdout)
+        self.assertIn("staged changes only", proc.stderr)
+
+
+class RefreshFailuresAreFailures(unittest.TestCase):
+    def test_a_failed_refresh_is_returned_and_exits_nonzero(self):
+        report = {"entries": [{"status": "UPDATED", "key": "dolphin-sys"},
+                              {"status": "OK", "key": "ppsspp-assets"}]}
+        with mock.patch.object(
+            check_buildbot_system.subprocess, "run",
+            return_value=subprocess.CompletedProcess([], 1),
+        ):
+            self.assertEqual(check_buildbot_system.update_changed(report), ["dolphin-sys"])
+        source = (REPO_ROOT / "scripts" / "check_buildbot_system.py").read_text(encoding="utf-8")
+        self.assertIn("failed = update_changed(report)", source)
+        self.assertIn("sys.exit(1)", source[source.index("failed = update_changed(report)"):])
+
+
+if __name__ == "__main__":
+    unittest.main()