ForumActivityTest fails due to custom toolbar

java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.

	at android.support.v7.app.AppCompatDelegateImplV7.setSupportActionBar(AppCompatDelegateImplV7.java:197)
	at android.support.v7.app.AppCompatActivity.setSupportActionBar(AppCompatActivity.java:129)
	at org.briarproject.briar.android.activity.BriarActivity.setUpCustomToolbar(BriarActivity.java:109)
	at org.briarproject.briar.android.forum.ForumActivity.onCreate(ForumActivity.java:66)
	at android.app.Activity.performCreate(Activity.java:5933)
	at org.robolectric.util.ReflectionHelpers.callInstanceMethod(ReflectionHelpers.java:195)
	at org.robolectric.util.ActivityController$1.run(ActivityController.java:122)
	at org.robolectric.shadows.ShadowLooper.runPaused(ShadowLooper.java:304)
	at org.robolectric.shadows.CoreShadowsAdapter$2.runPaused(CoreShadowsAdapter.java:45)
	at org.robolectric.util.ActivityController.create(ActivityController.java:118)
	at org.robolectric.util.ActivityController.create(ActivityController.java:129)
	at org.briarproject.briar.android.forum.ForumActivityTest.setUp(ForumActivityTest.java:93)