diff --git a/Rakefile b/Rakefile
index efde3b4..264a5be 100644
--- a/Rakefile
+++ b/Rakefile
@@ -2,8 +2,19 @@
 
 require "decidim/dev/common_rake"
 
+def fix_babel_config(path)
+  Dir.chdir(path) do
+    babel_config = "#{Dir.pwd}/babel.config.json"
+    File.delete(babel_config) if File.exist?(babel_config)
+    FileUtils.cp("#{__dir__}/babel.config.json", Dir.pwd)
+  end
+end
+
 desc "Generates a dummy app for testing"
-task test_app: "decidim:generate_external_test_app"
+task test_app: "decidim:generate_external_test_app" do
+  ENV["RAILS_ENV"] = "test"
+  fix_babel_config("spec/decidim_dummy_app")
+end
 
 desc "Generates a development app."
 task development_app: "decidim:generate_external_development_app"