Build assets automatically if necessary

In CI, these are unnecessary because done by preprocessing.
To test locally, you need to do it manually. If assets not exist, it will
fail when a run specific test, so force to build those only when necessary.

1 files changed, 7 insertions, 0 deletions

diff --git a/railties/test/isolation/abstract_unit.rb b/railties/test/isolation/abstract_unit.rb
index 3f1638a516..b0662e0159 100644
--- a/railties/test/isolation/abstract_unit.rb
+++ b/railties/test/isolation/abstract_unit.rb
@@ -488,7 +488,14 @@ Module.new do
     f.puts "require 'rails/all'"
   end
 
+  unless File.exist?("#{RAILS_FRAMEWORK_ROOT}/actionview/lib/assets/compiled/rails-ujs.js")
+    Dir.chdir("#{RAILS_FRAMEWORK_ROOT}/actionview") { `yarn build` }
+  end
+
   assets_path = "#{RAILS_FRAMEWORK_ROOT}/railties/test/isolation/assets"
+  unless Dir.exist?("#{assets_path}/node_modules")
+    Dir.chdir(assets_path) { `yarn install` }
+  end
   FileUtils.cp("#{assets_path}/package.json", "#{app_template_path}/package.json")
   FileUtils.cp("#{assets_path}/config/webpacker.yml", "#{app_template_path}/config/webpacker.yml")
   FileUtils.cp_r("#{assets_path}/config/webpack", "#{app_template_path}/config/webpack")