diff --git a/gcsfs/core.py b/gcsfs/core.py
index f425afc0..7308e9c2 100644
--- a/gcsfs/core.py
+++ b/gcsfs/core.py
@@ -596,7 +596,7 @@ async def _list_objects(self, path, prefix="", versions=False, **kwargs):
 
         # Don't cache prefixed/partial listings, in addition to
         # not using the inventory report service to do listing directly.
-        if not prefix and use_snapshot_listing is False:
+        if not prefix and not use_snapshot_listing:
             self.dircache[path] = out
         return out
 
diff --git a/gcsfs/retry.py b/gcsfs/retry.py
index 4bb860ba..42c73a51 100644
--- a/gcsfs/retry.py
+++ b/gcsfs/retry.py
@@ -58,15 +58,17 @@ class ChecksumError(Exception):
 )
 
 
+errs = list(range(500, 505)) + [
+    # Request Timeout
+    408,
+    # Too Many Requests
+    429,
+]
+errs = set(errs + [str(e) for e in errs])
+
+
 def is_retriable(exception):
     """Returns True if this exception is retriable."""
-    errs = list(range(500, 505)) + [
-        # Request Timeout
-        408,
-        # Too Many Requests
-        429,
-    ]
-    errs += [str(e) for e in errs]
     if isinstance(exception, HttpError):
         return exception.code in errs
 
diff --git a/gcsfs/tests/test_core.py b/gcsfs/tests/test_core.py
index 1415d66f..37912a54 100644
--- a/gcsfs/tests/test_core.py
+++ b/gcsfs/tests/test_core.py
@@ -26,12 +26,27 @@
 TEST_REQUESTER_PAYS_BUCKET = gcsfs.tests.settings.TEST_REQUESTER_PAYS_BUCKET
 
 
-def test_simple(gcs):
-    assert not GoogleCredentials.tokens
+def test_simple(gcs, monkeypatch):
+    monkeypatch.setattr(GoogleCredentials, "tokens", None)
     gcs.ls(TEST_BUCKET)  # no error
     gcs.ls("/" + TEST_BUCKET)  # OK to lead with '/'
 
 
+def test_dircache_filled(gcs):
+    assert not dict(gcs.dircache)
+    gcs.ls(TEST_BUCKET)
+    assert len(gcs.dircache) == 1
+    gcs.dircache[TEST_BUCKET][0]["CHECK"] = True
+    out = gcs.ls(TEST_BUCKET, detail=True)
+    assert [o for o in out if o.get("CHECK", None)]
+
+    gcs.invalidate_cache()
+    assert not dict(gcs.dircache)
+
+    gcs.find(TEST_BUCKET)
+    assert len(gcs.dircache)
+
+
 def test_many_connect(docker_gcs):
     from multiprocessing.pool import ThreadPool