Espresso is a testing framework used to write UI test cases. It automatically tests your actions with the UI of your application. The framework also ensures that your activity is started before the test run. It can be used to test across multiple applications. If used for testing outside application, you can perform only black box testing. as you cannot the classes inside the application.
Espresso has three components:
ViewMatchers: Allows to find the view in the current view library.
ViewActions: Allows to perform actions on the view
ViewAssertions: Allows to assert state of the view
Why Espresso?
It’s fast: It is really important to run test cases at a fast pace as there can be many tests. UI test takes time and is costly and it is possible that you might not be able to run all the tests.
It’s easy to setup: Setup process on local machines is easy and Android developers feel comfortable in the mobile SDK language which they use every day.
It’s less flaky: Automated DevOps process…
