DEVX-179: fix: strip [skip ci] tokens and prefer newest commit in squash titles

tests/unit/test_auto_merge.py

@@ -232,6 +232,40 @@ class TestExtractConventionalMsg:
         ]
         assert extract_conventional_msg(commits) == "random message"
 
+    def test_skip_ci_subjects_are_ineligible(self) -> None:
+        """[skip ci] commits must never become the merge title (REQ-1)."""
+        commits = [
+            {"commit": {"message": "ci: retrigger validation"}},
+            {"commit": {"message": "chore: update badge URLs to commit abc123 [skip ci]"}},
+        ]
+        assert extract_conventional_msg(commits) == "ci: retrigger validation"
+
+    def test_skip_ci_variants_excluded(self) -> None:
+        """All skip-token spellings are ineligible."""
+        for token in ("[skip ci]", "[ci skip]", "[skip actions]", "[actions skip]", "[SKIP CI]"):
+            commits = [
+                {"commit": {"message": "feat: real change"}},
+                {"commit": {"message": f"chore: noise {token}"}},
+            ]
+            assert extract_conventional_msg(commits) == "feat: real change"
+
+    def test_tie_prefers_newest_commit(self) -> None:
+        """Equal-priority ties resolve to the newest commit (REQ-2); the
+        API returns commits newest-first."""
+        commits = [
+            {"commit": {"message": "ci: add workflow_dispatch trigger"}},
+            {"commit": {"message": "ci: retrigger validation"}},
+        ]
+        assert extract_conventional_msg(commits) == "ci: add workflow_dispatch trigger"
+
+    def test_all_skip_ci_fallback_strips_token(self) -> None:
+        """When every commit carries [skip ci], the token is stripped so
+        the merge still triggers post-merge."""
+        commits = [
+            {"commit": {"message": "chore: noise [skip ci]"}},
+        ]
+        assert extract_conventional_msg(commits) == "chore: noise"
+
 
 # -- run_cmd --