django test method mock persists with call_command

Question

SSCCE example here:

first_app/tests/test_file.py

from unittest.mock import patch

from django.core.management import call_command
from django.test import TestCase


class TestWierdo(TestCase):

    @patch('first_app.class_a.method_to_import')
    def test_b(self, mock_obj2):
        call_command('this_is_command', item='abcd')
        print(mock_obj2.call_args)    
       # prints "i should be called for test_b, call('abcd')", this is good so far
       # will have issue here later.
        self.assertTrue(False)

first_app/management/commands/this_is_command.py

from django.core.management import BaseCommand

from first_app.class_a import method_to_call_from_command


class Command(BaseCommand):
    def add_arguments(self, parser):
        parser.add_argument(
            '--char',
            action='store',
            dest='item',
        )

    def handle(self, *args, **options):
        char = options['item']
        method_to_call_from_command(str(char))

first_app/class_a.py

from first_app.class_b import method_to_import


def method_to_call_from_command(a):
    print('i should be called for test_b')
    generated = method_to_import(a)
    return generated

first_app/class_b.py

def method_to_import(a):
    return

All is good, but let's add another test in TestWierdo class with a mistake:

class TestWierdo(TestCase):

    @patch('first_app.class_a.method_to_call_from_command') <- Notice wrong mock path here.
    # @patch('first_app.management.commands.this_is_command.method_to_call_from_command') <- correct one
    def test_a(self, mock_obj):
        call_command('this_is_command', item='test')  # commenting this line also fixes the issue
        print(mock_obj.call_args) # print 'test'
        self.assertTrue(False)

    @patch('first_app.class_a.method_to_import')
    def test_b(self, mock_obj2):
        call_command('this_is_command', item='abcd')
        print(mock_obj2.call_args)  <----- # print None !!!!, does not print "i should be called for test_b"
        self.assertTrue(False)

What is going on here? It seems like the mock persists from test_a. Commenting out call_command('this_is_command', item='test') or wrong mock patch decorator fixes the issue.

But why does wrong mock from the test_a affect test_b?

django test method mock persists with call_command

0 Answers0