tests: Check git commit data

Test that the git commit was made with the correct values in the
metadata. Primarily this is useful to make sure that commit authorship
is being done correctly.

tests/test_main.py

@@ -48,15 +48,59 @@ def _clear_environment(self):
         for var in unwanted_vars:
             os.environ.pop(var, None)
 
-    def _run_cmd(self, cmd):
-        return subprocess.run(cmd, cwd=self.test_dir.name, check=True)
+    def _run_cmd(self, cmd, **kwargs):
+        return subprocess.run(cmd, cwd=self.test_dir.name, check=True, **kwargs)
+
+    def _get_commit_data(self, rev="HEAD"):
+        data = {}
+        for name, fmt in [
+            ("commit", "%H"),
+            ("subject", "%s"),
+            ("body", "%b"),
+            ("author_name", "%an"),
+            ("author_email", "%ae"),
+            ("committer_name", "%cn"),
+            ("committer_email", "%ce"),
+        ]:
+            cmd = ["git", "show", "--no-patch", f"--pretty=format:{fmt}", rev]
+            proc = self._run_cmd(cmd, stdout=subprocess.PIPE)
+            output = proc.stdout.decode("utf-8")
+            data[name] = output
+
+        return data
 
     async def test_full_run(self):
         args1 = main.parse_cli_args(["--update", "--commit-only", self.manifest_path])
         self.assertEqual(await main.run_with_args(args1), (2, 0, True))
+
+        commit_data = self._get_commit_data()
+        self.assertEqual(commit_data["subject"], "Update 2 modules")
+        self.assertEqual(commit_data["author_name"], "Test Runner")
+        self.assertEqual(commit_data["author_email"], "test@localhost")
+        self.assertEqual(commit_data["committer_name"], "Test Runner")
+        self.assertEqual(commit_data["committer_email"], "test@localhost")
+
+        body_lines = commit_data["body"].splitlines()
+        self.assertEqual(len(body_lines), 2)
+        self.assertRegex(body_lines[0], r"^Update libXaw-1.0.12.tar.bz2 to ")
+        self.assertRegex(body_lines[1], r"^Update xterm-snapshots.git to ")
+
         args2 = main.parse_cli_args([self.manifest_path])
         self.assertEqual(await main.run_with_args(args2), (0, 0, False))
 
+    async def test_git_envvars(self):
+        os.environ["GIT_AUTHOR_NAME"] = "Some Guy"
+        os.environ["GIT_AUTHOR_EMAIL"] = "someguy@localhost"
+        args1 = main.parse_cli_args(["--update", "--commit-only", self.manifest_path])
+        self.assertEqual(await main.run_with_args(args1), (2, 0, True))
+
+        commit_data = self._get_commit_data()
+        self.assertEqual(commit_data["subject"], "Update 2 modules")
+        self.assertEqual(commit_data["author_name"], "Some Guy")
+        self.assertEqual(commit_data["author_email"], "someguy@localhost")
+        self.assertEqual(commit_data["committer_name"], "Test Runner")
+        self.assertEqual(commit_data["committer_email"], "test@localhost")
+
 
 class TestForceForkTristate(unittest.TestCase):
     def test_neither_fork_arg(self):