How do you generate dynamic (parameterized) unit tests in python?

Question

I have some kind of test data and want to create a unit test for each item. My first idea was to do it like this:

import unittest

l = [[\"foo\", \"a\", \"a\         


        

Answer 1

I'd been having trouble with a very particular style of parameterized tests. All our Selenium tests can run locally, but they also should be able to be run remotely against several platforms on SauceLabs. Basically, I wanted to take a large amount of already-written test cases and parameterize them with the fewest changes to code possible. Furthermore, I needed to be able to pass the parameters into the setUp method, something which I haven't seen any solutions for elsewhere.

Here's what I've come up with:

import inspect
import types

test_platforms = [
    {'browserName': "internet explorer", 'platform': "Windows 7", 'version': "10.0"},
    {'browserName': "internet explorer", 'platform': "Windows 7", 'version': "11.0"},
    {'browserName': "firefox", 'platform': "Linux", 'version': "43.0"},
]


def sauce_labs():
    def wrapper(cls):
        return test_on_platforms(cls)
    return wrapper


def test_on_platforms(base_class):
    for name, function in inspect.getmembers(base_class, inspect.isfunction):
        if name.startswith('test_'):
            for platform in test_platforms:
                new_name = '_'.join(list([name, ''.join(platform['browserName'].title().split()), platform['version']]))
                new_function = types.FunctionType(function.__code__, function.__globals__, new_name,
                                                  function.__defaults__, function.__closure__)
                setattr(new_function, 'platform', platform)
                setattr(base_class, new_name, new_function)
            delattr(base_class, name)

    return base_class

With this, all I had to do was add a simple decorator @sauce_labs() to each regular old TestCase, and now when running them, they're wrapped up and rewritten, so that all the test methods are parameterized and renamed. LoginTests.test_login(self) runs as LoginTests.test_login_internet_explorer_10.0(self), LoginTests.test_login_internet_explorer_11.0(self), and LoginTests.test_login_firefox_43.0(self), and each one has the parameter self.platform to decide what browser/platform to run against, even in LoginTests.setUp, which is crucial for my task since that's where the connection to SauceLabs is initialized.

Anyway, I hope this might be of help to someone looking to do a similar "global" parameterization of their tests!