> The isolation comes from the test implementation not the framework. There isn’t any framework out there that can guarantee/give you isolation.
I'm not sure what you mean by that. All the frameworks I ever used were designed with test isolation as the primary design goal. Even when you set shared test fixtures and setup/teardown code, all they provide is a way to share code across tests, which are by themselves independent and isolated. BDD-style frameworks are the notable exception in breaking away from the pattern of having isolation as a fundamental design trait. In fact, the whole reason why BDD-style tools require special support from testing frameworks is that they need to work around test isolation in order to share context across steps.
I'm not sure what you mean by that. All the frameworks I ever used were designed with test isolation as the primary design goal. Even when you set shared test fixtures and setup/teardown code, all they provide is a way to share code across tests, which are by themselves independent and isolated. BDD-style frameworks are the notable exception in breaking away from the pattern of having isolation as a fundamental design trait. In fact, the whole reason why BDD-style tools require special support from testing frameworks is that they need to work around test isolation in order to share context across steps.