chat: added clear_cache() function and test

tests/test_chat.py

@@ -300,3 +300,48 @@ class TestChatDB(CmmTestCase):
         # check that they now have the DB path
         self.assertEqual(chat_db.messages[6].file_path, pathlib.Path(self.db_path.name, '0007.txt'))
         self.assertEqual(chat_db.messages[7].file_path, pathlib.Path(self.db_path.name, '0008.yaml'))
+
+    def test_chat_db_clear(self) -> None:
+        # create a new ChatDB instance
+        chat_db = ChatDB.from_dir(pathlib.Path(self.cache_path.name),
+                                  pathlib.Path(self.db_path.name))
+        # check that Message.file_path is correct
+        self.assertEqual(chat_db.messages[0].file_path, pathlib.Path(self.db_path.name, '0001.txt'))
+        self.assertEqual(chat_db.messages[1].file_path, pathlib.Path(self.db_path.name, '0002.yaml'))
+        self.assertEqual(chat_db.messages[2].file_path, pathlib.Path(self.db_path.name, '0003.txt'))
+        self.assertEqual(chat_db.messages[3].file_path, pathlib.Path(self.db_path.name, '0004.yaml'))
+
+        # write the messages to the cache directory
+        chat_db.write_cache()
+        # check if the written files are in the cache directory
+        cache_dir_files = list(pathlib.Path(self.cache_path.name).glob('*'))
+        self.assertEqual(len(cache_dir_files), 4)
+
+        # now rewrite them to the DB dir and check for modified paths
+        chat_db.write_db()
+        db_dir_files = list(pathlib.Path(self.db_path.name).glob('*'))
+        self.assertEqual(len(db_dir_files), 4)
+        self.assertIn(pathlib.Path(self.db_path.name, '0001.txt'), db_dir_files)
+        self.assertIn(pathlib.Path(self.db_path.name, '0002.yaml'), db_dir_files)
+        self.assertIn(pathlib.Path(self.db_path.name, '0003.txt'), db_dir_files)
+        self.assertIn(pathlib.Path(self.db_path.name, '0004.yaml'), db_dir_files)
+
+        # add a new message with empty file_path
+        message_empty = Message(question=Question("What the hell am I doing here?"),
+                                answer=Answer("You don't belong here!"))
+        # and one for the cache dir
+        message_cache = Message(question=Question("What the hell am I doing here?"),
+                                answer=Answer("You're a creep!"),
+                                file_path=pathlib.Path(self.cache_path.name, '0005.txt'))
+        chat_db.add_msgs([message_empty, message_cache])
+
+        # clear the cache and check the cache dir
+        chat_db.clear_cache()
+        cache_dir_files = list(pathlib.Path(self.cache_path.name).glob('*'))
+        self.assertEqual(len(cache_dir_files), 0)
+        # make sure that the DB messages (and the new message) are still there
+        self.assertEqual(len(chat_db.messages), 5)
+        db_dir_files = list(pathlib.Path(self.db_path.name).glob('*'))
+        self.assertEqual(len(db_dir_files), 4)
+        # but not the message with the cache dir path
+        self.assertFalse(any(m.file_path == message_cache.file_path for m in chat_db.messages))