diff --git a/tests/test_x509.py b/tests/test_x509.py
index cf58324..3823120 100644
--- a/tests/test_x509.py
+++ b/tests/test_x509.py
@@ -251,6 +251,10 @@
 
 
 class TestNameAttribute(object):
+    def test_init_bad_oid(self):
+        with pytest.raises(TypeError):
+            x509.NameAttribute(None, 'value')
+
     def test_eq(self):
         assert x509.NameAttribute(
             x509.ObjectIdentifier('oid'), 'value'