Patterns of Testability

Testability requires interfaces for observing and controlling software, either built into the software itself or provided by the software ecosystem. Observability exposes the input and output data of components, as well as monitoring execution flow. Controllability provides the ability to change data and drive actions through the component interface. Without testability interfaces, defects are harder to find, reproduce, and fix. Manual testing can be improved by access to information these interfaces provide, while all automated testing requires them. Alan Myrvold shares software component diagrams that show patterns of testability. These patterns will help you architect and evaluate the observability and controllability of your system. Apply these testability patterns to describe and document your own testability interfaces. Learn new ways to think and talk about the testability of your software and create interfaces for a more robust test effort.