Shadows are sometimes hidden, sometimes seen, and can lead you to the real object. Why “Shadow?” Shadow objects are not quite Proxies, not quite Fakes, not quite Mocks or Stubs. Using byte code instrumentation Robolectric is able to weave in cross platform fake implementations to substitute for native code and add additional APIs to make testing possible. When an Android class is instantiated, Robolectric looks for a corresponding shadow class, and if it finds one it creates a shadow object to associate with it. Each shadow can modify or extend the behavior of a corresponding class in the Android OS. Robolectric fills these gaps with a set of classes known as Shadows. Inadequate testing APIs - Android includes next to no APIs suitable for testing.Out of process calls - There are no Android system services running on your development machine.Native code - Android native code cannot execute on your development machine.This means when your tests or code under test calls into the Android framework you get a more realistic experience as for the most part the same code is executed as would be on a real device. Robolectric works by creating a runtime environment that includes the real Android framework code.

Robolectric shadow log android studio