Locust (locust.io) is an open source load testing tool which allows you to write load tests in Python. This is a nice approach because you can leverage the full possibilities of this nice programming language and are not restricted to complicated and overloaded UIs to configure your tests. (you probably have an idea about which tool I am referring to)
The starting point of each load test is a so called locust-file which contains the code that is executed in order to run the test. Locust can be used to test all kind of technology but is per default optimized for http-based systems like REST services or web-UIs.
Doing REST calls and simple GET-requests is easy and they are pretty much self-explanatory:
In this example two simple get request is issued to the web sites "index.html" and "login.html". The task annotations define an action that a user is doing repeatedly.
When you have to support frameworks like JSF the challenges increase. For example when doing a JSF login with locust (python) you have to keep two things in mind:
- JSF uses a JSESSIONID which is set to a cookie and identifies the session of a user on the server. Therefore the client needs to save the JSESSIONID after login in order to make sure the session is not lost between the requests.
- JSF uses a view state to keep track of the JSF component tree on the server side. The view state ID has to be sent to the server otherwise an exception is thrown.