## Spy Object Brief ![[Spy Object.excalidraw.svg|100]] A [[Software construction/Testing/Test Doubles/Test Doubles|Test double]] that allows the Test to validate the behavior of the [[System Under Test]] by exposing the indirect outputs the [[System Under Test]] performes on the [[Spy Object]]. ## Illustration ![[Test-Spy-lifecycle.gif]] ## Sources http://xunitpatterns.com/Test%20Spy.html