diff --git a/stix2/test/test_utils.py b/stix2/test/test_utils.py
index cbe5b0f..4705ec8 100644
--- a/stix2/test/test_utils.py
+++ b/stix2/test/test_utils.py
@@ -82,3 +82,21 @@ def test_get_dict_invalid(data):
 ])
 def test_get_type_from_id(stix_id, typ):
     assert stix2.utils.get_type_from_id(stix_id) == typ
+
+
+def test_deduplicate(stix1_objs):
+    unique = stix2.utils.deduplicate(stix1_objs)
+
+    # Only 3 objects are unique
+    # 2 id's vary
+    # 2 modified times vary for a particular id
+
+    assert len(unique) == 3
+
+    ids = [obj['id'] for obj in unique]
+    mods = [obj['modified'] for obj in unique]
+
+    assert "indicator--d81f86b8-975b-bc0b-775e-810c5ad45a4f" in ids
+    assert "indicator--d81f86b9-975b-bc0b-775e-810c5ad45a4f" in ids
+    assert "2017-01-27T13:49:53.935Z" in mods
+    assert "2017-01-27T13:49:53.936Z" in mods