How can I decorate a Python unittest method to skip if a property I've previously evaluated isn't True?

Question

I'm writing a TestCase in Python using unittest, that looks something like this:

class MyTestCase(unittest.TestCase):
  def setUp(self):
    # ... check if I'm online - might result in True or False
    self.isOnline = True

  @unittest.skipIf(not self.isOnline, "Not online")
  def test_xyz(self):
    # do a test that relies on being online

However, this doesn't seem to work, I assume because @skipIf cannot use self outside the body of the function declaration. I know I can check the value of self.isOnline inside the test_xyz function and use skipTest instead, but this is less elegant. Are there any other options?

Answer 1

You could write your own decorator to which you pass the name of the flag:

def skipIfTrue(flag):
    def deco(f):
        def wrapper(self, *args, **kwargs):
            if getattr(self, flag):
                self.skipTest()
            else:
                f(self, *args, **kwargs)
        return wrapper
    return deco

Then in your class you would define the test method like this:

@skipIfTrue('isOnline')
def test_thing(self):
    print("A test")

Whether this is better than just checking in the method depends on the situation. If you are doing this with many methods, it could be better than writing the check in every one. On the other hand, if you're doing that, you might want to group them together and do one check to skip the entire suite.