Thanks Jose Alcérreca! This solution helped me realize refactoring from theAndroidViewModel to ViewModel will improve local JUnit testing by removing the need to create Application Context.

I recently refactored the main feed of Coinverse’s Open App with the Unidirectional Data Flow (UDF) pattern to organize app logic. A major expectation was that in doing so it would make JUnit testing easier.

I quickly hit this StackOverflow issue with theAndroidViewModel. During JUnit setup and creating the AndroidViewModel, Application Context is required, causing a runtime error.

Implementation

Directory — app > src > test > java

ExampleUnitTest.kt

import androidx.test.core.app.ApplicationProvider
val context = ApplicationProvider.getApplicationContext<Context>()

Error

java.lang.IllegalStateException: No instrumentation registered! Must run under a registering instrumentation.

Solution

By removing the Application Context dependency and using one of the Dependency Injection libraries to create components in the ViewModel (ie — Repository, Database, Analytics, and etc.), the error above may be avoided.