main: Set module names as title

If the length crosses 56 characters then the title breaks off to
multiple lines and becomes too verbose. So revert to the old message
to avoid that.

src/main.py

@@ -181,7 +181,12 @@ def commit_changes(changes: t.List[str]) -> CommittedChanges:
     log.info("Committing updates")
     body: t.Optional[str]
     if len(changes) > 1:
-        subject = "Update {} modules".format(len(changes))
+        module_names = set([i.split(":", 1)[0] for i in changes])
+        subj_string = "Update: " + ", ".join(module_names)
+        if len(subj_string) <= 56:
+            subject = subj_string
+        else:
+            subject = "Update {} modules".format(len(changes))
         body = "\n".join(changes)
         message = subject + "\n\n" + body
     else:

tests/test_main.py

@@ -74,7 +74,7 @@ async def test_full_run(self):
         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["subject"], "Update: libXaw, xterm")
         self.assertEqual(commit_data["author_name"], "Test Runner")
         self.assertEqual(commit_data["author_email"], "test@localhost")
         self.assertEqual(commit_data["committer_name"], "Test Runner")
@@ -95,7 +95,7 @@ async def test_git_envvars(self):
         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["subject"], "Update: libXaw, xterm")
         self.assertEqual(commit_data["author_name"], "Some Guy")
         self.assertEqual(commit_data["author_email"], "someguy@localhost")
         self.assertEqual(commit_data["committer_name"], "Test Runner")