diff --git a/test/unit/test_caches_local.py b/test/unit/test_caches_local.py
index 6fd68c72f..db2b21ff1 100644
--- a/test/unit/test_caches_local.py
+++ b/test/unit/test_caches_local.py
@@ -300,11 +300,13 @@ def patch_get_single_entry(mocker):
 def test_get_encryption_materials(patch_get_single_entry):
     cache = build_lcmc()
 
-    test = cache.get_encryption_materials(cache_key=sentinel.cache_key, plaintext_length=sentinel.plaintext_length)
+    plaintext_length = 42
+
+    test = cache.get_encryption_materials(cache_key=sentinel.cache_key, plaintext_length=plaintext_length)
 
     patch_get_single_entry.assert_called_once_with(sentinel.cache_key)
     patch_get_single_entry.return_value._update_with_message_bytes_encrypted.assert_called_once_with(
-        sentinel.plaintext_length
+        plaintext_length
     )
     assert test is patch_get_single_entry.return_value