diff --git a/tests/test_workflow_modules.py b/tests/test_workflow_modules.py
index d8e1d2c..4c10b6b 100644
--- a/tests/test_workflow_modules.py
+++ b/tests/test_workflow_modules.py
@@ -340,8 +340,10 @@ class TestCompositeColor:
 
         output = output_dir / "fg.png"
         assert output.is_file()
-        result = run_command([magick, "identify", "-format", "%[type]", str(output)])
-        assert result.stdout.strip() != "Grayscale"
+        from PIL import Image
+
+        with Image.open(output) as img:
+            assert img.mode != "L"
 
 
 has_workflow_tools = check_workflow_tools()