session.setServletContext(new MockServletContext());
HttpSessionEvent event = new HttpSessionEvent(session);
server.sessionCreated(event);
assertEquals(1, server.getActiveSessionCount());
server.sessionDestroyed(event);
assertEquals(0, server.getActiveSessionCount());
// 6 sessions created and 1 destroyed
server.sessionCreated(event);
server.sessionCreated(event);
server.sessionCreated(event);