When you see yourself repeating a number of assertions in your unit tests, or you have to think hard each time you make some kind of assertion, it’s time to create your own assertions, which wraps these complicated assertions into one single method call on your TestCase class. In the example below, I will create a custom assertion which would recognize the following JSON string as a “successful response”:

{"success":true}

Inside a TestCase we could run the following lines of code to verify the successfulness of the given JSON response string: