ActivityScenario

public final class ActivityScenario<A extends Activity> implements AutoCloseable, Closeable

ActivityScenario provides APIs to start and drive an Activity's lifecycle state for testing. It works with arbitrary activities and works consistently across different versions of the Android framework.

The ActivityScenario API uses State extensively. If you are unfamiliar with components, please read lifecycle before starting.

It is crucial to understand the difference between State and Event.

moveToState allows you to transition your Activity's state to CREATED, STARTED, RESUMED, or DESTROYED. There are two paths for an Activity to reach CREATED: after ON_CREATE happens but before ON_START, or after ON_STOP. ActivityScenario always moves the Activity's state using the second path. The same applies to STARTED.

DESTROYED is the terminal state. You cannot move your Activity to other state once it reaches to that state. If you want to test recreation of Activity instance, use recreate.

ActivityScenario does't clean up device state automatically and may leave the activity keep running after the test finishes. Call close in your test to clean up the state or use try-with-resources statement. This is optional but highly recommended to improve the stability of your tests. Also, consider using androidx.test.ext.junit.rules.ActivityScenarioRule.

This class is a replacement of ActivityController in Robolectric and ActivityTestRule in ATSL.

Following are the example of common use cases. 

Before:
  MyActivity activity = Robolectric.setupActivity(MyActivity.class);
  assertThat(activity.getSomething()).isEqualTo("something");

After:
  try(ActivityScenario<MyActivity> scenario = ActivityScenario.launch(MyActivity.class)) {
    scenario.onActivity(activity -> {
      assertThat(activity.getSomething()).isEqualTo("something");
    });
  }

Before:
  ActivityController<MyActivity> controller = Robolectric.buildActivity(MyActivity.class);
  controller.create().start().resume();  // Moves the activity state to State.RESUMED.
  controller.pause();    // Moves the activity state to State.STARTED. (ON_PAUSE is an event).
  controller.stop();     // Moves the activity state to State.CREATED. (ON_STOP is an event).
  controller.destroy();  // Moves the activity state to State.DESTROYED.

After:
  try(ActivityScenario<MyActivity> scenario = ActivityScenario.launch(MyActivity.class)) {
    scenario.moveToState(State.RESUMED);    // Moves the activity state to State.RESUMED.
    scenario.moveToState(State.STARTED);    // Moves the activity state to State.STARTED.
    scenario.moveToState(State.CREATED);    // Moves the activity state to State.CREATED.
    scenario.moveToState(State.DESTROYED);  // Moves the activity state to State.DESTROYED.
  }

Summary

Nested types
public interface ActivityScenario.ActivityAction<A extends Activity>

ActivityAction interface should be implemented by any class whose instances are intended to be executed by the main thread.

Public methods
void

Finishes the managed activity and cleans up device's state.
Instrumentation.ActivityResult

Waits for the activity to be finished and returns the activity result.
Lifecycle.State

Returns the current activity state.
static ActivityScenario<A>
<A extends Activity> launch(Class<A> activityClass)

Launches an activity of a given class and constructs ActivityScenario with the activity.
static ActivityScenario<A>
<A extends Activity> launch(Intent startActivityIntent)

Launches an activity by a given intent and constructs ActivityScenario with the activity.
static ActivityScenario<A>
<A extends Activity> launch(
    Class<A> activityClass,
    @Nullable Bundle activityOptions
)
static ActivityScenario<A>
<A extends Activity> launch(
    Intent startActivityIntent,
    @Nullable Bundle activityOptions
)

Launches an activity by a given intent and activity options and constructs ActivityScenario with the activity.
static @NonNull ActivityScenario<A>
<A extends Activity> launchActivityForResult(@NonNull Class<A> activityClass)

Launches an activity of a given class and constructs ActivityScenario with the activity.
static @NonNull ActivityScenario<A>
<A extends Activity> launchActivityForResult(@NonNull Intent startActivityIntent)

Launches an activity by a given intent and constructs ActivityScenario with the activity.
static @NonNull ActivityScenario<A>
<A extends Activity> launchActivityForResult(
    @NonNull Class<A> activityClass,
    @Nullable Bundle activityOptions
)

Launches an activity of a given class and activity options and constructs ActivityScenario with the activity.
static @NonNull ActivityScenario<A>
<A extends Activity> launchActivityForResult(
    @NonNull Intent startActivityIntent,
    @Nullable Bundle activityOptions
)

Launches an activity by a given intent and constructs ActivityScenario with the activity.
ActivityScenario<A>

Moves Activity state to a new state.
ActivityScenario<A>

Runs a given action on the current Activity's main thread.
ActivityScenario<A>

Recreates the Activity.

Public methods

close

public void close()

Finishes the managed activity and cleans up device's state. This method blocks execution until the activity becomes DESTROYED.

It is highly recommended to call this method after you test is done to keep the device state clean although this is optional.

You may call this method more than once. If the activity has been finished already, this method does nothing.

Avoid calling this method directly. Consider one of the following options instead: 

          
 Option 1, use try-with-resources:

 try (ActivityScenario<MyActivity> scenario = ActivityScenario.launch(MyActivity.class)) {
   // Your test code goes here.
 }

 Option 2, use ActivityScenarioRule:

@Rule
          
 public ActivityScenarioRule<MyActivity> rule = new ActivityScenarioRule<>(MyActivity.class);

@Test
          
 public void myTest() {
   ActivityScenario<MyActivity> scenario = rule.getScenario();
   // Your test code goes here.
 }

getResult

public Instrumentation.ActivityResult getResult()

Waits for the activity to be finished and returns the activity result.

ActivityScenario.launchActivityForResult() must be used to launch an Activity before this method is called.

Note: This method doesn't call finish. The activity must be finishing or finished otherwise this method will throws runtime exception after the timeout. 

Example:
  ActivityScenario<MyActivity> scenario =
     ActivityScenario.launchActivityForResult(MyActivity.class);
  // Let's say MyActivity has a button that finishes itself.
  onView(withId(R.id.finish_button)).perform(click());
  assertThat(scenario.getResult().getResultCode()).isEqualTo(Activity.RESULT_OK);
Returns
Instrumentation.ActivityResult

activity result of the activity that managed by this scenario class.
Throws
java.lang.IllegalStateException

when you call this method with an Activity that was not started by launchActivityForResult

getState

public Lifecycle.State getState()

Returns the current activity state. The possible states are CREATED, STARTED, RESUMED, and DESTROYED.

This method cannot be called from the main thread except in Robolectric tests.

launch

public static ActivityScenario<A> <A extends Activity> launch(Class<A> activityClass)

Launches an activity of a given class and constructs ActivityScenario with the activity. Waits for the lifecycle state transitions to be complete. Typically the initial state of the activity is RESUMED but can be in another state. For instance, if your activity calls finish from your onCreate, the state is DESTROYED when this method returns.

If you need to supply parameters to the start activity intent, use launch.

If you need to get the activity result, use launchActivityForResult.

This method cannot be called from the main thread except in Robolectric tests.

Parameters
Class<A> activityClass

an activity class to launch
Returns
ActivityScenario<A>

ActivityScenario which you can use to make further state transitions
Throws
java.lang.AssertionError

if the lifecycle state transition never completes within the timeout

launch

public static ActivityScenario<A> <A extends Activity> launch(Intent startActivityIntent)

Launches an activity by a given intent and constructs ActivityScenario with the activity. Waits for the lifecycle state transitions to be complete. Typically the initial state of the activity is RESUMED but can be in another state. For instance, if your activity calls finish from your onCreate, the state is DESTROYED when this method returns.

If you need to get the activity result, use launchActivityForResult.

This method cannot be called from the main thread except in Robolectric tests.

Parameters
Intent startActivityIntent

an intent to start the activity
Returns
ActivityScenario<A>

ActivityScenario which you can use to make further state transitions
Throws
java.lang.AssertionError

if the lifecycle state transition never completes within the timeout

launch

public static ActivityScenario<A> <A extends Activity> launch(
    Class<A> activityClass,
    @Nullable Bundle activityOptions
)
Parameters
Class<A> activityClass

an activity class to launch
@Nullable Bundle activityOptions

an activity options bundle to be passed along with the intent to start activity.
See also
launch

launch

public static ActivityScenario<A> <A extends Activity> launch(
    Intent startActivityIntent,
    @Nullable Bundle activityOptions
)

Launches an activity by a given intent and activity options and constructs ActivityScenario with the activity. @see #launch(Intent)

Parameters
Intent startActivityIntent

an intent to start the activity
@Nullable Bundle activityOptions

an activity options bundle to be passed along with the intent to start activity.

launchActivityForResult

public static @NonNull ActivityScenario<A> <A extends Activity> launchActivityForResult(@NonNull Class<A> activityClass)

Launches an activity of a given class and constructs ActivityScenario with the activity. Waits for the lifecycle state transitions to be complete. Typically the initial state of the activity is RESUMED but can be in another state. For instance, if your activity calls finish from your onCreate, the state is DESTROYED when this method returns. Broadcasts activity result.

If you need to supply parameters to the start activity intent, use launchActivityForResult.

This method cannot be called from the main thread except in Robolectric tests.

Parameters
@NonNull Class<A> activityClass

an activity class to launch
Returns
@NonNull ActivityScenario<A>

ActivityScenario which you can use to make further state transitions
Throws
java.lang.AssertionError

if the lifecycle state transition never completes within the timeout

launchActivityForResult

public static @NonNull ActivityScenario<A> <A extends Activity> launchActivityForResult(@NonNull Intent startActivityIntent)

Launches an activity by a given intent and constructs ActivityScenario with the activity. Waits for the lifecycle state transitions to be complete. Typically the initial state of the activity is RESUMED but can be in another state. For instance, if your activity calls finish from your onCreate, the state is DESTROYED when this method returns. Broadcasts activity result.

This method cannot be called from the main thread except in Robolectric tests.

If you are using AndroidX based activities, use androidx.activity.result.ActivityResult instead of this method. See https://developer.android.com/training/basics/intents/result#test

Parameters
@NonNull Intent startActivityIntent

an intent to start the activity
Returns
@NonNull ActivityScenario<A>

ActivityScenario which you can use to make further state transitions
Throws
java.lang.AssertionError

if the lifecycle state transition never completes within the timeout

launchActivityForResult

public static @NonNull ActivityScenario<A> <A extends Activity> launchActivityForResult(
    @NonNull Class<A> activityClass,
    @Nullable Bundle activityOptions
)

Launches an activity of a given class and activity options and constructs ActivityScenario with the activity. @see #launchActivityForResult(Class)

Parameters
@NonNull Class<A> activityClass

an activity class to launch
@Nullable Bundle activityOptions

an activity options bundle to be passed along with the intent to start activity.

launchActivityForResult

public static @NonNull ActivityScenario<A> <A extends Activity> launchActivityForResult(
    @NonNull Intent startActivityIntent,
    @Nullable Bundle activityOptions
)

Launches an activity by a given intent and constructs ActivityScenario with the activity. @see #launchActivityForResult(Intent)

Parameters
@NonNull Intent startActivityIntent

an intent to start the activity
@Nullable Bundle activityOptions

an activity options bundle to be passed along with the intent to start activity.

moveToState

public ActivityScenario<A> moveToState(Lifecycle.State newState)

Moves Activity state to a new state.

If a new state and current state are the same, it does nothing. It accepts CREATED, STARTED, RESUMED, and DESTROYED.

DESTROYED is the terminal state. You cannot move the state to other state after the activity reaches that state.

The activity must be at the top of the back stack (excluding internal facilitator activities started by this library), otherwise AssertionError may be thrown. If the activity starts another activity (such as DialogActivity), make sure you close these activities and bring back the original activity foreground before you call this method.

This method cannot be called from the main thread except in Robolectric tests.

Throws
java.lang.IllegalArgumentException

if unsupported newState is given
java.lang.IllegalStateException

if Activity is destroyed, finished or finishing
java.lang.AssertionError

if Activity never becomes requested state

onActivity

public ActivityScenario<A> onActivity(ActivityScenario.ActivityAction<A> action)

Runs a given action on the current Activity's main thread.

Note that you should never keep Activity reference passed into your action because it can be recreated at anytime during state transitions.

Throws
java.lang.IllegalStateException

if Activity is destroyed, finished or finishing

recreate

public ActivityScenario<A> recreate()

Recreates the Activity.

A current Activity will be destroyed after its data is saved into android.os.Bundle with onSaveInstanceState, then it creates a new Activity with the saved Bundle. After this method call, it is ensured that the Activity state goes back to the same state as its previous state.

This method cannot be called from the main thread except in Robolectric tests.

Throws
java.lang.IllegalStateException

if Activity is destroyed, finished or finishing
java.lang.AssertionError

if Activity never be re-created