Handling setup/teardown

To fully convert a TestCase subclass to pytest style, we need to replace unittest with pytest's idioms. We have already seen how to do that with self.assert* methods in the previous section, by using unittest2pytest. But what can we do do about setUp and tearDown methods?

As we learned previously, autouse fixtures work just fine in TestCase subclasses, so they are a natural way to replace setUp and tearDown methods. Let's use the example from the previous section.

 

After converting the assert statements, the first thing to do is to remove the unittest.TestCase subclassing:

class Test(unittest.TestCase):
    ...

This becomes the following:

class Test:
    ...

Next, we need to transform the setup/teardown methods into fixture equivalents:

    @classmethod
    def setUpClass(cls):
        cls.temp_dir = Path(tempfile.mkdtemp())
        cls.filepath = cls.temp_dir / "data.csv"
        cls.filepath.write_text(DATA.strip())

    @classmethod
    def tearDownClass(cls):
      ...