diff --git a/test/test_img_math.rb b/test/test_img_math.rb
index 33f7d347..4f0e35d8 100644
--- a/test/test_img_math.rb
+++ b/test/test_img_math.rb
@@ -88,7 +88,7 @@ def test_make_math_image
 
   def compare_images(image1, image2)
     MiniMagick.errors = false
-    compare = MiniMagick::Tool::Compare.new
+    compare = MiniMagick.compare
     compare << '-fuzz'
     compare << '10%'
     compare.metric('AE')