Testing randomness and time

Code that depends on external influences such as date, time or chance is particularly difficult to test. If implemented incorrectly, such tests quickly lead to an unstable test suite that is no longer trusted.

Here, I explain the challenges of testing time-dependent or random-based code and show you strategies for isolated and reproducible testing of this code.

If you want to be sure that software works properly, you have to test it continuously. Tools such as PHPUnit are constantly being improved, as are best practices for their use.

It doesn't matter whether you already have many years of experience testing PHP software with PHPUnit or are just getting started in the world of testing, for example in our training courses Test Automation with PHPUnit or Advanced PHPUnit: When it comes to testing software, there is always something new to learn and old patterns to rethink.

In Tester's Corner, we concisely cover a topic related to automated software testing every month.

• Testing code that looks at the clock
• Testing code that works with randomness
• Increase confidence in your test suite

Tester's Corner is aimed at all developers who test their software with PHPUnit. Whether you are a beginner or an experienced user of PHPUnit, there is always something new to learn here.

Prerequisites are (at least initial) practical experience with PHPUnit and knowledge of object-oriented programming in PHP. The necessary basics are taught in the training courses Test Automation with PHPUnit and OOP Done Right.

• Understand PHPUnit, from the basics to advanced problem solving
• Gain comprehensive knowledge of lesser-known features and techniques
• Continuously optimise your test strategy to adapt it to new requirements.