[Django]-A DRY way of writing similar unit tests in python

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3👍

✅

What are you trying to do is essentially a parameterized test. This feature isn’t included in standard django or python unittest modules, but a number of libs provide it: nose-parameterized, py.test, ddt

My favorite so far is ddt: it resembles NUnit-JUnit style parameterized tests most, pretty lightweight, don’t get in your way and does not require dedicated test runner (like nose-parameterized do). The way it can help you is that it modifies test name to include all parameters, so you would clearly see which test case failed by looking at a test name.

With ddt your example would look like this:

import ddt

@ddt.ddt
class TestProcessCreateAgencyOfferAndDispatch(TestCase):

    @ddt.data(TYPE_A, TYPE_B, TYPE_C)
    def test_foo_bar_type(self, type):
        self.assertTrue(foo(bar=type))

In such case names will look like test_foo_bar_type__TYPE_A (technically, it constructs it something like [test_name]__[repr(parameter_1)]__[repr(parameter_2)]).

As a bonus, it is much cleaner (no helper method), and you get three methods instead of one. The advantage here is that you can test various code paths in a method and get one test case per each path (but a certain amount of thinking is needed, sometimes it’s better to have a dedicated test for some of code paths)

👤J0HN

0👍

Most TestCase assertion methods, including assertTrue, take an optional msg argument.

If you change your BAR_TYPES tuple to include the variable names, then you can include this in the message that is shown when the assertion fails.

class TestProcessCreateAgencyOfferAndDispatch(TestCase):
    BAR_TYPES = (
        ('TYPE_A', TYPE_A),
        ('TYPE_B', TYPE_B),
        ('TYPE_C', TYPE_C),
        ...
    )

    def _foo_test(self, var_name, bar_type):
        self.assertTrue(foo(bar=bar_type), var_name)

    def test_foo_bar_type(self):
        for (var_name, bar_type) in BAR_TYPES:
            _foo_test(bar=bar_type), var_name=var_name)
👤Alasdair

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