In this section, I am going to write test code. Here we"ll discuss a little bit philosophy of testing but more writing tests. So the first test I am going to write is a controller test. the reason I am writing controller test is because a lot is going in controller as it is taking some request an responding in the response. As you can see the job of the index action here is to load the post using the model and then saving it as instance variable and returning some kind of response. The simplest test we can write is to test the response and which is returning right kind of response. In this case I have a post controller test which is generated when i generated the controller. This is a simple test. Here what can I do is write where get is and index is actually the and the simplest say is get :index HTTP verb index action assert_response :success Lets run the test: In the console write rake rake run our test As you can see here test has passed