robolectric/src/main/java/org/robolectric/android/internal/LocalActivityInvoker.java
@Override
  public Intent getIntentForActivity(Class<? extends Activity> activityClass) {
    PackageManager packageManager = getTargetContext().getPackageManager();
    ComponentName componentName = new ComponentName(getTargetContext(), activityClass);
    Intent intent = Intent.makeMainActivity(componentName);
    if (packageManager.resolveActivity(intent, 0) != null) {
      return intent;
    }
    return Intent.makeMainActivity(new ComponentName(getContext(), activityClass));
  }
@Override
  public Intent getIntentForActivity(Class<? extends Activity> activityClass) {
    PackageManager packageManager = getTargetContext().getPackageManager();
    ComponentName componentName = new ComponentName(getTargetContext(), activityClass);
    Intent intent = Intent.makeMainActivity(componentName);
    if (packageManager.resolveActivity(intent, 0) != null) {
      return intent;
    }
    return Intent.makeMainActivity(new ComponentName(getContext(), activityClass));
  }
This implementation makes sure, that the activity you are trying to launch exists