Up until now, you have seen what's already been implemented, what is possible to do out of the box, and some additional functionalities like the fixtures.
Now let's have a look at what testing a REST interface entails; the default functional tests available in Codeception are executed by PHPBrowser, and the interface exposed to interact with it is quite limited and can only be used to deal and interact with the markup output by the web server. The REST module provided by Codeception is something we would love.
Just to cite a few of the features available, you'll have functions to set and read headers, such as
haveHttpHeader(), and specific methods to call HTTP requests towards our interface, ...