What is InstantTaskExecutorRule

Defining InstantTaskExecutorRule

• This is a Junit rule used in test cases for tests that use android architecture components.
• One such scenario is for the execution of livedata that happens instantly so that we can use the values in the test.

Gradle

testImplementation ‘android.arch.core:core-testing:1.1.1’

Usage in code

@get:Rule
val instantTaskExecutorRule = InstantTaskExecutorRule()

More information

• This rule swaps the background executor used by the architecture components with a different one that executes each task synchronously.
• This is very important when writing the unit tests
• Basically, it helps to execute tests one after another in a single thread all at once