chore: update _closed internal variable in connect function

Author: kgala2

google/cloud/sql/connector/connector.py

@@ -243,6 +243,8 @@ def connect(
         # connect runs sync database connections on background thread.
         # Async database connections should call 'connect_async' directly to
         # avoid hanging indefinitely.
+        if self._closed:
+            raise RuntimeError("Cannot connect using a closed Connector.")
         connect_future = asyncio.run_coroutine_threadsafe(
             self.connect_async(instance_connection_string, driver, **kwargs),
             self._loop,
@@ -467,6 +469,7 @@ def close(self) -> None:
                 self._loop.call_soon_threadsafe(self._loop.stop)
             # wait for thread to finish closing (i.e. loop to stop)
             self._thread.join()
+        self._closed = True
 
     async def close_async(self) -> None:
         """Helper function to cancel the cache's tasks

tests/unit/test_connector.py

@@ -482,7 +482,7 @@ async def test_connect_async_closed_connector(
         connector._client = fake_client
         await connector.close_async()
         # wait for close to complete
-        await asyncio.sleep(0.1)
+        # await asyncio.sleep(0.1)
         with pytest.raises(RuntimeError) as exc_info:
             await connector.connect_async(
                 "test-project:test-region:test-instance",
@@ -501,7 +501,7 @@ def test_connect_closed_connector(
     with Connector(credentials=fake_credentials) as connector:
         connector._client = fake_client
         connector.close()
-        time.sleep(3.1)
+        # time.sleep(3.1)
         with pytest.raises(RuntimeError) as exc_info:
             connector.connect(
                 "test-project:test-region:test-instance",