add test checking that precompiling assets performs caching

railties/test/application/assets_test.rb

@@ -8,7 +8,7 @@ class AssetsTest < Test::Unit::TestCase
     include Rack::Test::Methods
 
     def setup
-      build_app
+      build_app(:initializers => true)
       boot_rails
     end
 
@@ -61,6 +61,16 @@ def app
       end
     end
 
+    test "precompile properly performs caching" do
+      app_file "app/assets/stylesheets/application.css.erb", "<%= asset_path('rails.png') %>"
+
+      capture(:stdout) do
+        Dir.chdir(app_path){ `bundle exec rake assets:precompile` }
+      end
+      file = Dir["#{app_path}/public/assets/application-*.css"].first
+      assert_match /\/assets\/rails-([0-z]+)\.png/, File.read(file)
+    end
+
     test "assets are cleaned up properly" do
       app_file "public/assets/application.js", "alert();"
       app_file "public/assets/application.css", "a { color: green; }"