diff --git a/test/diff_test.rb b/test/diff_test.rb
index fe9aa27dc..96617c878 100644
--- a/test/diff_test.rb
+++ b/test/diff_test.rb
@@ -1145,9 +1145,7 @@ def test_patch
 \\ No newline at end of file
 EOS
 
-    expected.force_encoding('binary') if expected.respond_to?(:force_encoding)
-
-    assert_equal expected, diff.patch
+    assert_equal expected.b, diff.patch
   end
 
   def test_patch_compact