Question

When writing unit tests, I sometimes cut and paste a test and don’t remember to change the method name. This results in overwriting the previous test, effectively hiding it and preventing it from running. For example;

class WidgetTestCase(unittest.TestCase):

  def test_foo_should_do_some_behavior(self):
    self.assertEquals(42, self.widget.foo())

  def test_foo_should_do_some_behavior(self):
    self.widget.bar()
    self.assertEquals(314, self.widget.foo())

In this case, only the latter test would get called. Is there a way of programmatically catching this sort of error, short of parsing the raw source code directly?

Answer 1

If you run Pylint over your code, it will inform you when you have overwritten another method:

For example, I ran this:

class A(object):
    def blah(self):
        print("Hello, World!")

    def blah(self):
        print("I give up!")

In this online Pylint checker. Besides all the missing docstrings and such, I get this:

E: 5:A.blah: method already defined line 2

Alternatively, via the command line:

python -m pyflakes .

Output:

.\blah.py:5:5 redefinition of unused 'blah' from line 2