setup_module（）与py.test中的顶级语句有何不同？

Question

If I don't have any teardown, do I need to use setup_module, or can I just use top-level statements?

=== test_1.py ===
foo = 3
def test_foo(): assert foo == 3

=== test_2.py 
def setup_module(m): m.foo = 3
def test_foo(): assert foo == 3

Will py.test execute all the top-level statements in order, and before it executes the first test?

Thanks!

Answer 1

It seems like py.test will evaluate your top-level-statements before any test, so test_1.py will work.

However, when you are writing tests, it is generally not a good idea to have any top-level-statements. You should try to structure your tests into Test Cases (a Class that holds your related test code) and which tests specific features of your application. So, if you take your code ( test_2.py ) and turn it into a Test Case, it will look something like this:

def setup_module(module):
    module.TestFoo.foo = 3

class TestFoo:
    def test_foo(self):
        assert self.foo == 3

This way, you can keep adding all the related tests to TestFoo and even add more than one TestCase per module (although it's usually best to have each TestCase in it's own file).

Regarding your teardown_module question, you only need a teardown when you need to restore the application state to its initial state (removing newly created items, etc) or to clean up hanging connections (closing files, sockets, etc). In this case, since your setup_module is not doing anything that needs any clean up, teardown is not needed and py.test won't complain the lack of it.