diff --git a/tests/test_pdfforms_fill.py b/tests/test_pdfforms_fill.py
index bdec074..a6ac821 100644
--- a/tests/test_pdfforms_fill.py
+++ b/tests/test_pdfforms_fill.py
@@ -345,7 +345,7 @@ def test_main_generate_fdf():
     else:
         pytest.fail(f"pattern {pattern!r} not found in FDF output")
 
-@pytest.mark.skipUnless(PDFTK, "need pdftk installed")
+@pytest.mark.skipif(not PDFTK, reason="need pdftk installed")
 @pytest.mark.xfail(reason="`pdftk fill_form` expects a full PDF")
 def test_main_fill_pdf():
     arglist = [