Try fix

mars/conftest.py

@@ -21,6 +21,7 @@
 
 from mars.config import option_context
 from mars.core.mode import is_kernel_mode, is_build_mode
+from mars.lib.aio.lru import clear_all_alru_caches
 from mars.oscar.backends.router import Router
 from mars.oscar.backends.ray.communication import RayServer
 from mars.serialization.ray import register_ray_serializers, unregister_ray_serializers
@@ -30,6 +31,11 @@
 MARS_CI_BACKEND = os.environ.get("MARS_CI_BACKEND", "mars")
 
 
+@pytest.fixture(autouse=True)
+def auto_cleanup(request):
+    request.addfinalizer(clear_all_alru_caches)
+
+
 @pytest.fixture(scope="module")
 def ray_start_regular_shared(request):  # pragma: no cover
     yield from _ray_start_regular(request)

mars/lib/aio/lru.py

@@ -23,13 +23,23 @@
 # THE SOFTWARE.
 
 import asyncio
+import os
+import weakref
 from collections import OrderedDict
 from functools import _CacheInfo, _make_key, partial, wraps
 
 
 __version__ = "1.0.2"
 
-__all__ = ("alru_cache",)
+__all__ = ("alru_cache", "clear_all_alru_caches")
+
+_is_ci = (os.environ.get("CI") or "0").lower() in ("1", "true")
+_all_wrapped = weakref.WeakSet()
+
+
+def clear_all_alru_caches():
+    for wrapped in _all_wrapped:
+        wrapped.cache_clear()
 
 
 def unpartial(fn):
@@ -206,6 +216,8 @@ async def wrapped(*fn_args, **fn_kwargs):
         wrapped.close = partial(_close, wrapped)
         wrapped.open = partial(_open, wrapped)
 
+        if _is_ci:
+            _all_wrapped.add(wrapped)
         return wrapped
 
     if fn is None: