Capture Django Query Context

I’m writing this down because it came in very handy recently when testing a Django queryset, and I seem to have a hard time remembering this feature exists.

In django.test.utils, there is a CaptureQueriesContext context manager which enables you to fetch the context for a query. (My latest use case was to verify that some additional constraints in a queryset did not result in an N+1 query.)

Justin Thurman has a good example:

from django.db import connection
from django.test.utils import CaptureQueriesContext

def test_foo():
  with CaptureQueriesContext(connection) as ctx:
    # run some SQL queries
    print(ctx.captured_queries)
    # run assertions after printing if you want to guarantee that print fires