In integrating Signon.js with QUnit and jsTestDriver, I found that if
the tests threw an exception or an assertion failed, then jsTestDriver
would not stop running and failed to report the error (at least the
Eclipse plug-in).  I determined this was due to starting Sinon's
fakeServer in setup(), but teardown() was never called to stop it.  I've
added a try catch around the test.call(context) to catch errors and call
teardown to make sure the fakeServer is stopped.