A workaround that is strongly inspired from https://youtrack.jetbrains.com/issue/IDEA-140041 is to start your main class with the test classpath (which includes the embedded servlet.)
Steps (IntelliJ 16):
Run->Edit Configurations->Add new configuration-> PickApplicationtype.- Set
Main classto<your.main.class> - Set
Use classpath of moduleto<*>_test(the test module!) OkandRunit!