With an automated testing framework in core, Drupal is now far along the road to a practice of Test-driven development. But there's one thing missing: a complete, in-depth, up-to-date tutorial on how to actually write these tests. Although there is the SimpleTest Automator module to help you create these tests through the user interface, it is currently imperfect and under development, so this post will be a tutorial on writing these tests manually.

Testing resources

Here's just a general list of resources we should keep handy while writing our test:

• Testing API functions - This is a quick cheat sheet of some functions that are very helpful during testing. These include controlling the internal testing browser, creating users with specific permissions, and simulating clicking on links that appear in the page.
• Available assertions - Assertions are how you determine whether your code is working or not - you assert that it should be working, and let the testing framework handle the rest for you. This is a library on the assertions that are available to use in our testing framework.

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