@Test
public void testDisconnectListner() {

    final String sessionId = "my-session-id";
    final SessionDisconnectEvent mockEvent = mock(SessionDisconnectEvent.class);
    when(mockEvent.getSessionId()).thenReturn(sessionId);
    // Create mock Manager
    final WebSocketConsumersManager mockManager = mock(WebSocketConsumersManager.class);
    // Create our listener
    final PresenceEventListener eventListener = new PresenceEventListener(mockManager);
    // Call method
    eventListener.handleSessionDisconnect(mockEvent);
    // validate
    verify(mockManager, times(1)).removeConsumersForSessionId(eq(sessionId));
}