Property-Based Testing

In property-based testing you state a general property that should hold for all inputs, and the framework generates many random inputs to try to falsify it. This finds edge cases hand-written examples miss.

An example test checks one case: reverse(List(1,2,3)) == List(3,2,1). A property states a rule: reversing twice yields the original list, for any list. The framework checks that rule on hundreds of generated lists.