diff --git a/actioncable/test/javascript_package_test.rb b/actioncable/test/javascript_package_test.rb
index 421eab2d60..948f98e686 100644
--- a/actioncable/test/javascript_package_test.rb
+++ b/actioncable/test/javascript_package_test.rb
@@ -4,10 +4,16 @@
 
 class JavascriptPackageTest < ActiveSupport::TestCase
   def test_compiled_code_is_in_sync_with_source_code
-    compiled_file = File.expand_path("../app/assets/javascripts/action_cable.js", __dir__)
+    compiled_files = %w[
+      app/assets/javascripts/actioncable.js
+      app/assets/javascripts/actioncable.esm.js
+      app/assets/javascripts/action_cable.js
+    ].map do |file|
+      Pathname(file).expand_path("#{__dir__}/..")
+    end
 
-    assert_no_changes -> { File.read(compiled_file) } do
-      system "yarn build"
+    assert_no_changes -> { compiled_files.map(&:read) } do
+      system "yarn build", exception: true
     end
   end
 end