diff --git a/tests/test_filters.py b/tests/test_filters.py
index f709761d9a84043602a47005d662db9a0cb560e6..a6a5b03f4c0d88e23575016d183cc961eff7f24e 100644
--- a/tests/test_filters.py
+++ b/tests/test_filters.py
@@ -183,3 +183,6 @@ def test_audit_date(entry):
         assert actual is None
     else:
         assert actual == entry.date
+
+def test_iter_unique():
+    assert list(filters.iter_unique('1213231')) == list('123')