In case if heat installation failed, your tests fail to without descriptive massage. We should cover such situation too. So you need to add in SetUp(or more great place in class set up method) verification is heat available (as example for neutron we request network list) some of light-weight operation. If it fails - invoke self.fail method with descriptive message like heat is unavailable, please see documentation(link or place where user can see how to resolve the problem)