Negative Testing: Broad Properties
Explore how to use broad properties in negative testing within property-based development. This lesson guides you through testing beyond happy paths by defining general properties that uncover less obvious errors. You will learn to write and patch properties for robust Erlang applications, improving error handling and consistency verification.
We'll cover the following...
Negative tests
An interesting aspect of the code and tests we have written so far is that the list of items being bought is generated through the list of supported items. Designing the test case from the price list shows a lack of tests looking for unexpected use cases. Our tests are positive, happy-path tests, validating that everything is operating as it should. Negative tests, by comparison, try to specifically exercise underspecified scenarios to find what happens in less happy paths.
Our current properties are good. We don’t want to modify them or make them more complex. Instead, we’ll write a few broad properties that test more general properties of the code and see if the requirements we had in place are actually consistent. On their own, broad (and often vague) properties are not too useful, but they serve as great anchors to ...