Simplify the process of adding shared tests for python code.
This is a class-level annotation that adds tests to the
unittest.TestCase subclass. It takes as input a list of functions that
each take the self argument. These functions will automatically have
test_ prepended to them, so you don't have to do that.
You can also optionally specify kwargs to be passed in to all functions (as kwargs).
See the tests for examples of using this.