feat: run the PR checks with one command

tests/test_contributing_text.py

@@ -65,7 +65,7 @@ class BeforeOpeningAPullRequest(unittest.TestCase):
 
         text = (REPO_ROOT / "CONTRIBUTING.md").read_text(encoding="utf-8")
         section = text.split("## Before opening a PR", 1)[1].split("\n## ", 1)[0]
-        block = _re.search(r"```bash\n(.*?)```", section, _re.S).group(1)
+        block = "".join(_re.findall(r"```bash\n(.*?)```", section, _re.S))
         for command in ("validate_pr.py --changed", "validate_schemas.py --source-only",
                         "unittest discover"):
             self.assertIn(command, block)
@@ -217,3 +217,68 @@ class TheGuideRebuildsWhenItsPinsMove(unittest.TestCase):
             (REPO_ROOT / ".github" / "workflows" / "deploy-site.yml").read_text(encoding="utf-8"))
         paths = deploy[True]["push"]["paths"]
         self.assertIn(".github/workflows/validate.yml", paths)
+
+
+class OneCommandRunsTheChecks(unittest.TestCase):
+    """A contributor copied ten commands by hand before a pull request, and
+    skipping one (refresh_data_dirs) failed the pack tests with no hint."""
+
+    CHECK = re.compile(r"(?:xargs -0 |run: |^\s*)((?:python3?\.?8? -m unittest|python scripts/\w+\.py"
+                       r"|vermin|npm (?:ci|run build)))")
+
+    def test_every_check_ci_runs_is_a_step(self):
+        import pr_checks
+
+        workflow = (REPO_ROOT / ".github" / "workflows" / "validate.yml").read_text(encoding="utf-8")
+        ran = {m.group(1) for line in workflow.splitlines()
+               if not line.strip().startswith("#") for m in [self.CHECK.search(line)] if m}
+        self.assertGreaterEqual(len(ran), 10)
+        steps = [step.command for step in pr_checks.STEPS]
+        for check in sorted(ran):
+            with self.subTest(check=check):
+                self.assertTrue(any(command.startswith(check) for command in steps))
+
+    def test_steps_keep_ci_order(self):
+        import pr_checks
+
+        workflow = (REPO_ROOT / ".github" / "workflows" / "validate.yml").read_text(encoding="utf-8")
+        order = [workflow.index(key) for key in (
+            "refresh_data_dirs.py", "run: python scripts/generate_site.py",
+            "npm run build --prefix website", "python -m unittest discover",
+            "validate_site.py")]
+        self.assertEqual(order, sorted(order))
+        commands = [step.command for step in pr_checks.STEPS]
+        positions = [next(i for i, c in enumerate(commands) if key in c) for key in (
+            "refresh_data_dirs.py", "generate_site.py", "npm run build",
+            "unittest discover", "validate_site.py")]
+        self.assertEqual(positions, sorted(positions))
+
+    def test_the_guide_gives_the_runner_and_what_it_runs(self):
+        import pr_checks
+
+        text = generate_readme.generate_contributing()
+        section = text.split("## Before opening a PR", 1)[1].split("\n## ", 1)[0]
+        self.assertIn("python scripts/pr_checks.py\n", section)
+        for step in pr_checks.STEPS:
+            with self.subTest(step=step.command):
+                self.assertIn(step.command, section)
+
+    def test_a_missing_tool_is_reported_and_a_failure_does_not_stop_the_run(self):
+        import contextlib
+        import io
+
+        import pr_checks
+
+        steps = (
+            pr_checks.Step("python -c raise(SystemExit(3))", "fails"),
+            pr_checks.Step("no-such-tool-here --x", "absent", needs="no-such-tool-here",
+                           provider="nothing"),
+            pr_checks.Step("python -c pass", "passes"),
+        )
+        out = io.StringIO()
+        with contextlib.redirect_stdout(out):
+            code = pr_checks.run(steps)
+        self.assertEqual(code, 1)
+        self.assertIn("FAILED   python -c raise(SystemExit(3)) (exit 3)", out.getvalue())
+        self.assertIn("NOT RUN  no-such-tool-here --x", out.getvalue())
+        self.assertIn("1/3 checks passed", out.getvalue())