Question

With two models:

class Model1(models.Model):
    attribute = models.CharField(max_length=100)

class Model2(models.Model):
    target = models.ForeignKey(Model1)

And a unittest tests.py:

class Model1Test(TestCase):
    def test_make_new_model_and_save():
        m = Model1()
        m.attribute = 'test values'
        m.save()

class Model2Test(TestCase):
    def test_make_new_model_and_save():
        # Make new Model1 to FK to
        m = Model1()
        m.attribute = 'test values'
        m.save()   

        m2 = Model2()
        m2.target = m
        m2.save()

I would like to just call the unittest function defined within Model1’s test class, rather than duplicating the code again in order to test Model2. This I imagine to be like:

class Model1Test(TestCase):
    def test_make_new_model_and_save():
        m = Model1()
        m.attribute = 'test values'
        m.save()
        return m

class Model2Test(TestCase):
    def test_make_new_model_and_save():
        # Make new Model1 to FK to
        m = Model1Test('test_make_new_model_and_save')

        m2 = Model2()
        m2.target = m
        m2.save()

But this doesn’t seem to work and I immediately find myself in the internals of the unit testing framework. I can’t find many references to this sort of thing, so being new to unit testing I feel I’ve taken a wrong turn somewhere.

Is there ‘normal’ method of reusing unit tests, or is my approach flawed?

Answer 1

This is really just a question about objects and classes in Python. The answer is to define a common superclass that contains the initialization code you want, inherit both Model1Test and Model2Test from it, and call it from both.

class CommonSetUp(TestCase):
    def make_new_model_and_save():
        m = Model1()
        m.attribute = 'test values'
        m.save()
        return m

class Model2Test(CommonSetUp):
    def test_make_new_model_and_save():
        self.make_new_model_and_save()
        self.assertTrue(...your assertions here...)

class Model2Test(CommonSetUp):
    def test_make_new_model_and_save():
        self.make_new_model_and_save()

        m2 = Model2()
        m2.target = m
        m2.save()

        self.assertTrue(...your assertions here...)