diff --git a/tests/storage/test__base.py b/tests/storage/test__base.py
index 2598dbe0a7..8e69b1e9cc 100644
--- a/tests/storage/test__base.py
+++ b/tests/storage/test__base.py
@@ -20,83 +20,11 @@ from mock import Mock
 from twisted.internet import defer
 
 from synapse.util.async_helpers import ObservableDeferred
-from synapse.util.caches.deferred_cache import DeferredCache
 from synapse.util.caches.descriptors import cached
 
 from tests import unittest
 
 
-class DeferredCacheTestCase(unittest.HomeserverTestCase):
-    def prepare(self, reactor, clock, homeserver):
-        self.cache = DeferredCache("test")
-
-    def test_empty(self):
-        failed = False
-        try:
-            self.cache.get("foo")
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
-
-    def test_hit(self):
-        self.cache.prefill("foo", 123)
-
-        self.assertEquals(self.cache.get("foo"), 123)
-
-    def test_invalidate(self):
-        self.cache.prefill(("foo",), 123)
-        self.cache.invalidate(("foo",))
-
-        failed = False
-        try:
-            self.cache.get(("foo",))
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
-
-    def test_eviction(self):
-        cache = DeferredCache("test", max_entries=2)
-
-        cache.prefill(1, "one")
-        cache.prefill(2, "two")
-        cache.prefill(3, "three")  # 1 will be evicted
-
-        failed = False
-        try:
-            cache.get(1)
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
-
-        cache.get(2)
-        cache.get(3)
-
-    def test_eviction_lru(self):
-        cache = DeferredCache("test", max_entries=2)
-
-        cache.prefill(1, "one")
-        cache.prefill(2, "two")
-
-        # Now access 1 again, thus causing 2 to be least-recently used
-        cache.get(1)
-
-        cache.prefill(3, "three")
-
-        failed = False
-        try:
-            cache.get(2)
-        except KeyError:
-            failed = True
-
-        self.assertTrue(failed)
-
-        cache.get(1)
-        cache.get(3)
-
-
 class CacheDecoratorTestCase(unittest.HomeserverTestCase):
     @defer.inlineCallbacks
     def test_passthrough(self):
diff --git a/tests/util/caches/test_deferred_cache.py b/tests/util/caches/test_deferred_cache.py
index 9b6acdfc43..9717be56b6 100644
--- a/tests/util/caches/test_deferred_cache.py
+++ b/tests/util/caches/test_deferred_cache.py
@@ -18,12 +18,41 @@ from functools import partial
 
 from twisted.internet import defer
 
-import synapse.util.caches.deferred_cache
+from synapse.util.caches.deferred_cache import DeferredCache
 
 
 class DeferredCacheTestCase(unittest.TestCase):
+    def test_empty(self):
+        cache = DeferredCache("test")
+        failed = False
+        try:
+            cache.get("foo")
+        except KeyError:
+            failed = True
+
+        self.assertTrue(failed)
+
+    def test_hit(self):
+        cache = DeferredCache("test")
+        cache.prefill("foo", 123)
+
+        self.assertEquals(cache.get("foo"), 123)
+
+    def test_invalidate(self):
+        cache = DeferredCache("test")
+        cache.prefill(("foo",), 123)
+        cache.invalidate(("foo",))
+
+        failed = False
+        try:
+            cache.get(("foo",))
+        except KeyError:
+            failed = True
+
+        self.assertTrue(failed)
+
     def test_invalidate_all(self):
-        cache = synapse.util.caches.deferred_cache.DeferredCache("testcache")
+        cache = DeferredCache("testcache")
 
         callback_record = [False, False]
 
@@ -62,3 +91,47 @@ class DeferredCacheTestCase(unittest.TestCase):
         # letting the other lookup complete should do nothing
         d1.callback("result1")
         self.assertIsNone(cache.get("key1", None))
+
+    def test_eviction(self):
+        cache = DeferredCache(
+            "test", max_entries=2, apply_cache_factor_from_config=False
+        )
+
+        cache.prefill(1, "one")
+        cache.prefill(2, "two")
+        cache.prefill(3, "three")  # 1 will be evicted
+
+        failed = False
+        try:
+            cache.get(1)
+        except KeyError:
+            failed = True
+
+        self.assertTrue(failed)
+
+        cache.get(2)
+        cache.get(3)
+
+    def test_eviction_lru(self):
+        cache = DeferredCache(
+            "test", max_entries=2, apply_cache_factor_from_config=False
+        )
+
+        cache.prefill(1, "one")
+        cache.prefill(2, "two")
+
+        # Now access 1 again, thus causing 2 to be least-recently used
+        cache.get(1)
+
+        cache.prefill(3, "three")
+
+        failed = False
+        try:
+            cache.get(2)
+        except KeyError:
+            failed = True
+
+        self.assertTrue(failed)
+
+        cache.get(1)
+        cache.get(3)