test(api): inject disposable databases before API startup (#194)

tests/test_api_database_isolation.py

@@ -0,0 +1,71 @@
+"""API fixtures never open the configured database before installing test state."""
+
+import unittest.mock
+
+from py.api import PromptManagerAPI
+
+
+class TestAPIDatabaseIsolation(unittest.TestCase):
+    def test_injected_database_never_constructs_the_configured_database(self):
+        database = unittest.mock.MagicMock()
+        database.cleanup_duplicates.return_value = 0
+        with (
+            unittest.mock.patch(
+                "py.api.PromptDatabase", side_effect=AssertionError("default DB opened")
+            ) as factory,
+            unittest.mock.patch("py.api.get_logger"),
+        ):
+            api = PromptManagerAPI(db=database)
+        self.assertIs(api.db, database)
+        factory.assert_not_called()
+        database.cleanup_duplicates.assert_called_once_with()
+
+    def test_falsey_injected_database_is_still_used(self):
+        database = unittest.mock.MagicMock()
+        database.__bool__.return_value = False
+        database.cleanup_duplicates.return_value = 0
+        with (
+            unittest.mock.patch(
+                "py.api.PromptDatabase", side_effect=AssertionError("default DB opened")
+            ) as factory,
+            unittest.mock.patch("py.api.get_logger"),
+        ):
+            api = PromptManagerAPI(db=database)
+        self.assertIs(api.db, database)
+        factory.assert_not_called()
+
+    def test_default_runtime_construction_still_uses_the_configured_factory(self):
+        database = unittest.mock.MagicMock()
+        database.cleanup_duplicates.return_value = 2
+        with (
+            unittest.mock.patch(
+                "py.api.PromptDatabase", return_value=database
+            ) as factory,
+            unittest.mock.patch("py.api.get_logger") as logger,
+        ):
+            api = PromptManagerAPI()
+        self.assertIs(api.db, database)
+        factory.assert_called_once_with()
+        logger.return_value.info.assert_any_call(
+            "Startup cleanup: removed 2 duplicate prompts"
+        )
+
+    def test_injected_cleanup_failure_is_logged_without_falling_back_to_default(self):
+        database = unittest.mock.MagicMock()
+        database.cleanup_duplicates.side_effect = RuntimeError("test cleanup")
+        with (
+            unittest.mock.patch(
+                "py.api.PromptDatabase", side_effect=AssertionError("default DB opened")
+            ) as factory,
+            unittest.mock.patch("py.api.get_logger") as logger,
+        ):
+            api = PromptManagerAPI(db=database)
+        self.assertIs(api.db, database)
+        factory.assert_not_called()
+        logger.return_value.error.assert_called_once_with(
+            "Startup cleanup failed: test cleanup"
+        )
+
+
+if __name__ == "__main__":
+    unittest.main()