XCallback xCallback = new XCallback( mock( XCallbackConfiguration.class ) );
XCallbackListener listener = mock( XCallbackListener.class );
XCallbackListener listener2 = mock( XCallbackListener.class );
xCallback.addXCallbackListener( listener );
xCallback.addXCallbackListener( listener2 );
JsonObject parameters = new JsonObject();
parameters.add( "errorCode", "42" );
parameters.add( "errorMessage", "foo" );
environment.dispatchNotify( "Error", parameters );
InOrder order = inOrder( listener, listener2 );
order.verify( listener ).onError( "42", "foo" );