diff --git a/tests/test_deck.py b/tests/test_deck.py
index e0f11beb4..2fe538c95 100644
--- a/tests/test_deck.py
+++ b/tests/test_deck.py
@@ -146,6 +146,17 @@ def test_deck_006(ref_string):
     assert len(deck5._keywords) == len(deck3._keywords) + len(deck4._keywords)
 
 
+@pytest.mark.keywords
+def test_deck_copy():
+    import copy
+    x = Deck()
+    x.append(kwd.Mat001(mid=99))
+    y = copy.deepcopy(x)
+    y.keywords[0].mid = 100
+    assert x.keywords[0].mid == 99
+    assert y.keywords[0].mid == 100
+
+
 @pytest.mark.keywords
 def test_deck_read_parameters():
     """Test reading a deck with parameters."""