Let's check gc

aiodocker/docker.py

@@ -86,6 +86,7 @@ def __init__(
         ssl_context: Optional[ssl.SSLContext] = None,
         api_version: str = "auto",
     ) -> None:
+        self._init = False
         docker_host = url  # rename
         if docker_host is None:
             docker_host = os.environ.get("DOCKER_HOST", None)
@@ -166,6 +167,7 @@ def __init__(
         # legacy aliases
         self.pull = self.images.pull
         self.push = self.images.push
+        self._init = True
 
     async def __aenter__(self) -> "Docker":
         return self
@@ -181,7 +183,10 @@ async def __aexit__(
     async def close(self) -> None:
         await self.events.stop()
         await self.session.close()
-        await self.connector.close()
+
+    def __del__(self) -> None:
+        if self._init and not self.session.closed:
+            raise RuntimeError("A Docker instance must be explicitly closed")
 
     async def auth(self, **credentials: Any) -> Dict[str, Any]:
         response = await self._query_json("auth", "POST", data=credentials)

tests/conftest.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import asyncio
 import os
 import sys
 import traceback
@@ -95,6 +96,7 @@ async def docker(testing_images):
             raise RuntimeError(f"Cannot find docker API version for {version}")
 
     docker = Docker(**kwargs)
+    print(asyncio.get_running_loop())
     try:
         yield docker
     finally: