diff --git a/railties/lib/rails/test_unit/line_filtering.rb b/railties/lib/rails/test_unit/line_filtering.rb
index e8b891d07b..f8ca77fe4a 100644
--- a/railties/lib/rails/test_unit/line_filtering.rb
+++ b/railties/lib/rails/test_unit/line_filtering.rb
@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require "method_source"
 require "rails/test_unit/runner"
 
 module Rails