ExploratoryTesting

Exploratory testing is a manual testing technique designed to find contradictions (i.e. bugs or UX issues) among a software system's behaviors.

During exploratory testing, the tester interacts with the system in a freeform way, not following a particular test plan. They build a mental Model of how the system works, which guides them toward areas of the system where bugs are most likely to occur. They try to Falsify the model by comparing it to the system's actual Behavior. In WhiteBox exploratory testing, the tester also looks at the code to build their model. Often, this scrutiny reveals CornerCases where the system behaves in an unexpected way because its Developers did not have a coherent mental model of what it should do in that case.

Here is a video of exploratory testing in action: https://www.youtube.com/watch?v=xvUKVpOCqAY