assertNumQueries example

tests.py

from django.test import TransactionTestCase
from .services import my_function_that_hits_the_db

class MyTest(TransactionTestCase):

    def test_db_performance(self):
        # called directly
        self.assertNumQueries(7, my_function_that_hits_the_db)
        # used as a context manager
        with self.assertNumQueries(2):
            Person.objects.create(name="Aaron")
            Person.objects.create(name="Beth")