diff --git a/tests/test_mgf.py b/tests/test_mgf.py
index 5d690fca..3c8f942b 100644
--- a/tests/test_mgf.py
+++ b/tests/test_mgf.py
@@ -152,7 +152,7 @@ def test_write_single(self):
             for spectrum in self.spectra:
                 mgf.write(spectra=spectrum, output=tmpfile)
 
-        self.assertEqual(len(ws), 2)
+        self.assertGreaterEqual(len(ws), 2)
         for w in ws:
             self.assertTrue(issubclass(w.category, UserWarning))
             self.assertTrue("discouraged" in str(w.message))