Add changelog CLI command and tests (see ChatGPT conversation 2025-12-08) https://chatgpt.com/share/69370663-4eb8-800f-bba9-4f5c42682450

tests/unit/pkgmgr/test_changelog.py

@@ -0,0 +1,142 @@
+from __future__ import annotations
+
+import unittest
+from unittest.mock import patch
+
+from pkgmgr.changelog import generate_changelog
+from pkgmgr.git_utils import GitError
+from pkgmgr.cli_core.commands.changelog import _find_previous_and_current_tag
+
+
+class TestGenerateChangelog(unittest.TestCase):
+    @patch("pkgmgr.changelog.run_git")
+    def test_generate_changelog_default_range_no_merges(self, mock_run_git) -> None:
+        """
+        Default behaviour:
+        - to_ref = HEAD
+        - from_ref = None
+        - include_merges = False -> adds --no-merges
+        """
+        mock_run_git.return_value = "abc123 (HEAD -> main) Initial commit"
+
+        output = generate_changelog(cwd="/repo")
+
+        self.assertEqual(
+            output,
+            "abc123 (HEAD -> main) Initial commit",
+        )
+        mock_run_git.assert_called_once()
+        args, kwargs = mock_run_git.call_args
+
+        # Command must start with git log and include our pretty format.
+        self.assertEqual(args[0][0], "log")
+        self.assertIn("--pretty=format:%h %d %s", args[0])
+        self.assertIn("--no-merges", args[0])
+        self.assertIn("HEAD", args[0])
+        self.assertEqual(kwargs.get("cwd"), "/repo")
+
+    @patch("pkgmgr.changelog.run_git")
+    def test_generate_changelog_with_range_and_merges(self, mock_run_git) -> None:
+        """
+        Explicit range and include_merges=True:
+        - from_ref/to_ref are combined into from..to
+        - no --no-merges flag
+        """
+        mock_run_git.return_value = "def456 (tag: v1.1.0) Some change"
+
+        output = generate_changelog(
+            cwd="/repo",
+            from_ref="v1.0.0",
+            to_ref="v1.1.0",
+            include_merges=True,
+        )
+
+        self.assertEqual(output, "def456 (tag: v1.1.0) Some change")
+        mock_run_git.assert_called_once()
+        args, kwargs = mock_run_git.call_args
+
+        cmd = args[0]
+        self.assertEqual(cmd[0], "log")
+        self.assertIn("--pretty=format:%h %d %s", cmd)
+        # include_merges=True -> no --no-merges flag
+        self.assertNotIn("--no-merges", cmd)
+        # Range must be exactly v1.0.0..v1.1.0
+        self.assertIn("v1.0.0..v1.1.0", cmd)
+        self.assertEqual(kwargs.get("cwd"), "/repo")
+
+    @patch("pkgmgr.changelog.run_git")
+    def test_generate_changelog_giterror_returns_error_message(self, mock_run_git) -> None:
+        """
+        If Git fails, we do NOT raise; instead we return a human readable error string.
+        """
+        mock_run_git.side_effect = GitError("simulated git failure")
+
+        result = generate_changelog(cwd="/repo", from_ref="v0.1.0", to_ref="v0.2.0")
+
+        self.assertIn("[ERROR] Failed to generate changelog", result)
+        self.assertIn("simulated git failure", result)
+        self.assertIn("v0.1.0..v0.2.0", result)
+
+    @patch("pkgmgr.changelog.run_git")
+    def test_generate_changelog_empty_output_returns_info(self, mock_run_git) -> None:
+        """
+        Empty git log output -> informational message instead of empty string.
+        """
+        mock_run_git.return_value = "   \n   "
+
+        result = generate_changelog(cwd="/repo", from_ref=None, to_ref="HEAD")
+
+        self.assertIn("[INFO] No commits found for range 'HEAD'", result)
+
+
+class TestFindPreviousAndCurrentTag(unittest.TestCase):
+    def test_no_semver_tags_returns_none_none(self) -> None:
+        tags = ["foo", "bar", "v1.2", "v1.2.3.4"]  # all invalid for SemVer
+        prev_tag, cur_tag = _find_previous_and_current_tag(tags)
+
+        self.assertIsNone(prev_tag)
+        self.assertIsNone(cur_tag)
+
+    def test_latest_tags_when_no_target_given(self) -> None:
+        """
+        When no target tag is given, the function should return:
+        (second_latest_semver_tag, latest_semver_tag)
+        based on semantic version ordering, not lexicographic order.
+        """
+        tags = ["v1.0.0", "v1.2.0", "v1.1.0", "not-a-tag"]
+        prev_tag, cur_tag = _find_previous_and_current_tag(tags)
+
+        self.assertEqual(prev_tag, "v1.1.0")
+        self.assertEqual(cur_tag, "v1.2.0")
+
+    def test_single_semver_tag_returns_none_and_that_tag(self) -> None:
+        tags = ["v0.1.0"]
+        prev_tag, cur_tag = _find_previous_and_current_tag(tags)
+
+        self.assertIsNone(prev_tag)
+        self.assertEqual(cur_tag, "v0.1.0")
+
+    def test_with_target_tag_in_the_middle(self) -> None:
+        tags = ["v1.0.0", "v1.1.0", "v1.2.0"]
+        prev_tag, cur_tag = _find_previous_and_current_tag(tags, target_tag="v1.1.0")
+
+        self.assertEqual(prev_tag, "v1.0.0")
+        self.assertEqual(cur_tag, "v1.1.0")
+
+    def test_with_target_tag_first_has_no_previous(self) -> None:
+        tags = ["v1.0.0", "v1.1.0"]
+        prev_tag, cur_tag = _find_previous_and_current_tag(tags, target_tag="v1.0.0")
+
+        self.assertIsNone(prev_tag)
+        self.assertEqual(cur_tag, "v1.0.0")
+
+    def test_unknown_target_tag_returns_none_none(self) -> None:
+        tags = ["v1.0.0", "v1.1.0"]
+        prev_tag, cur_tag = _find_previous_and_current_tag(tags, target_tag="v2.0.0")
+
+        self.assertIsNone(prev_tag)
+        self.assertIsNone(cur_tag)
+
+
+if __name__ == "__main__":
+    unittest.main()