diff --git a/test/icat/test_lru_cache.py b/test/icat/test_lru_cache.py
new file mode 100644
index 00000000..f413e7e1
--- /dev/null
+++ b/test/icat/test_lru_cache.py
@@ -0,0 +1,26 @@
+from unittest.mock import MagicMock
+
+from cachetools import cached
+
+from datagateway_api.common.config import config
+from datagateway_api.common.icat.lru_cache import ExtendedLRUCache
+
+
+class TestLRUCache:
+    def test_valid_cache_creation(self):
+        test_cache = ExtendedLRUCache()
+        assert test_cache.maxsize == config.get_client_cache_size()
+
+    def test_valid_popitem(self, icat_client):
+        test_cache = ExtendedLRUCache()
+
+        test_cache.popitem = MagicMock(side_effect=test_cache.popitem)
+
+        @cached(cache=test_cache)
+        def get_cached_client(cache_number):
+            return icat_client
+
+        for cache_number in range(config.get_client_cache_size() + 1):
+            get_cached_client(cache_number)
+
+        assert test_cache.popitem.called