Get returns the instance of S which must have been previously registered using Register.

Register allows a suite of type s to be later retrieved using Get.

Run is a helper method which calls m.Run and the Teardown function, returning the exit code from m.Run, or 1 if an error occured during Teardown.

Teardown runs the Teardown method on registered suites who ran their Setup methods.

Base is a placeholder type which can be embedded into other suites if they don't need to implement setup or teardown methods.

A Suite holds some shared state for multiple tests.