Since section 6.7.2 of the spec says "The
session scope is active: ... when the container calls any HttpSessionListener", the TCK should also test if the scope is active during webapp undeploy and during server shutdown, as HttpSessionListeners ar called at that time also.

I guess a simple HttpSessionListener that accesses the session context during sessionDestroyed() (and doesn't catch any exceptions) is enough to test this, since the test will fail if there are any problems during the test undeployment process.