Add tests for api_only configuration setting

railties/test/application/configuration_test.rb

@@ -1393,5 +1393,20 @@ module ApplicationTests
 
       assert_equal 'unicorn', Rails.application.config.my_custom_config['key']
     end
+
+    test "api_only is false by default" do
+      app 'development'
+      refute Rails.application.config.api_only
+    end
+
+    test "api_only generator config is set when api_only is set" do
+      add_to_config <<-RUBY
+        config.api_only = true
+      RUBY
+      app 'development'
+
+      Rails.application.load_generators
+      assert Rails.configuration.api_only
+    end
   end
 end