Assertions
Assertions allow you to declaratively write tests.
This should cover most of your testing needs. For complex tests, you can write test scripts.
Example:
Accessing headers
To access HTTP response headers, you can query res.headers.['xyz] (whereas xyz is the lower-cased header name like x-powered-byfor example). Be aware that accessing inexistent headers will result in an error, as an inexistent header is not an empty string, but "undefined".