CODEWITHSUNDEEP
pythonunit-testingdjango-rest-frameworkmockingpatch
Shahzad Farukh
Shahzad Farukh

Reputation: 337

Mock Patch check parent class method call

I want to unit test this class method update

class EmployeeUpdateSerializer(serializers.ModelSerializer):

    def update(self, instance, data):
        shift_types = data.pop('shift_types', None)
        instance = super().update(instance, data)
        self.update_shift_type(instance, shift_types)
        return instance

I am doing this

class TestEmployeeUpdateSerializer(TestCase):
    def setUp(self):
        self.company, self.user, self.header = create_user_session()
        self.serializer = EmployeeUpdateSerializer()

    def test_update(self):
        employee = self.user

        with patch.object(self.serializer, 'update') as update:
            with patch.object(self.serializer, 'update_shift_type') as update_shift_type:
                res = self.serializer.update(employee, dict())

                update.assert_called_once_with(employee, dict())
                update_shift_type.assert_called_once_with(employee, None)

                self.assertEqual(res, employee)

But this gives me an error

    Traceback (most recent call last):
  File "/Users/shahzadfarukh/my-croft/backend/account/tests/test_employee_serializers.py", line 222, in test_update
    update_shift_type.assert_called_once_with(employee, None)
  File "/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/unittest/mock.py", line 830, in assert_called_once_with
    raise AssertionError(msg)
AssertionError: Expected 'update_shift_type' to be called once. Called 0 times.

Please help me! is something I am doing wrong?

Upvotes: 0

Views: 914

Answers (1)

MrBean Bremen
MrBean Bremen

Reputation: 16815

You have mocked update, so its original code won't get called. If you want to test what update calls, you have to call the original version, and mock only functions/methods called within the update. Assuming the base class is imported like import serializers, you could do something like this (untested)

class TestEmployeeUpdateSerializer(TestCase):
    def setUp(self):
        self.company, self.user, self.header = create_user_session()
        self.serializer = EmployeeUpdateSerializer()

     @patch('serializers.ModelSerializer.update')
     @patch('serializers.ModelSerializer.update_shift_type')
     def test_update(self, mocked_update_shift_type, mocked_update):
         employee = self.user
         res = self.serializer.update(employee, dict())
         mocked_update.assert_called_once_with(employee, dict())
         mocked_update_shift_type.assert_called_once_with(employee, None)
         self.assertEqual(res, employee)

Upvotes: 2

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