diff --git a/test/rdoc/test_rdoc_generator_json_index.rb b/test/rdoc/test_rdoc_generator_json_index.rb
index 6b69337b45..30b9a4d174 100644
--- a/test/rdoc/test_rdoc_generator_json_index.rb
+++ b/test/rdoc/test_rdoc_generator_json_index.rb
@@ -105,7 +105,7 @@ def test_generate
     generated_file = Pathname(File.join @tmpdir, 'js/navigation.js')
 
     # This is dirty hack on JRuby
-    assert orig_file.mtime.inspect == generated_file.mtime.inspect,
+    assert_equal orig_file.mtime.inspect, generated_file.mtime.inspect,
       '.js files should be the same timestamp of original'
 
     json = File.read 'js/search_index.js'