Why do you use the AndroidJUnitRunner when running UI tests?
Notice: AndroidJUnitRunner lets us run JUnit3/4-style tests on Android Devices
a. The test runner facilitates loading your test package and the app under test onto a device or emulator, runs the test, and reports the results.
b. The test runner creating screenshots of each screen that displayed while tests are executed.
c. The test runner facilitates parallelization of test classes by providing for each test class.
d. The test runner facilitates interacting with visible elements on a device, regardless of the activity or fragment that has focus.