Warning: See here for limitations when running Robolectric tests via Android Studio when using the Hilt Gradle plugin.
Setting the test application
Hilt’s testing APIs are built to be agnostic of the particular testing environment; however, the instructions for setting up the application class in your test will depend on whether you are using Robolectric or Android instrumentation tests.
For Robolectric tests, the application can be set either locally using
@Config or globally using robolectric.properties. For Hilt tests, the
application must either be HiltTestApplication or one of Hilt’s
custom test applications.
Note: This setup is not particular to Hilt. See the official Robolectric documentation for more details.
Using @Config
The Hilt application class can be set locally using
@Config. To set the application, just annotate the test (or test method) with
@Config and set the value of the annotation to the desired application class.
@HiltAndroidTest
@Config(application = HiltTestApplication.class)
public class FooTest {...}
@HiltAndroidTest
@Config(application = HiltTestApplication::class)
class FooTest {...}
Using robolectric.properties
The Hilt application class can be set globally using the
robolectric.properties file. To set the application, just create the
robolectric.properties file in the appropriate resources package, and set
the Hilt test application class.
application=dagger.hilt.android.testing.HiltTestApplication
This approach can be useful when a test needs to run in both Robolectric and
Android instrumentation environments, since the @Config annotation cannot be
used with Android instrumentation tests.