django how to see sql query when running tests?

If you want to print/log all SQL queries from the tests, try subclassing TestCase like this:

from django.conf import settings
from django.template import Template, Context
import sys
from django.db import connection
from django.test import TestCase

class LoggingTestCase(TestCase):

  @staticmethod
  def setUpClass():
    # The test runner sets DEBUG to False. Set to True to enable SQL logging.
    settings.DEBUG = True
    super(LoggingTestCase, LoggingTestCase).setUpClass()

  @staticmethod
  def tearDownClass():
    super(LoggingTestCase, LoggingTestCase).tearDownClass()

    time = sum([float(q['time']) for q in connection.queries])
    t = Template("{{count}} quer{{count|pluralize:\"y,ies\"}} in {{time}} seconds:\n\n{% for sql in sqllog %}[{{forloop.counter}}] {{sql.time}}s: {{sql.sql|safe}}{% if not forloop.last %}\n\n{% endif %}{% endfor %}")
    print >> sys.stderr, t.render(Context({'sqllog': connection.queries, 'count': len(connection.queries), 'time': time}))

    # Empty the query list between TestCases.    
    connection.queries = []

Then use LoggingTestCase instead of TestCase as the base class in your tests. Just remember to call this tearDownClass if you override it.


Another option is to use CaptureQueriesContext (tested with pytest).

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


def test_foo():
    with CaptureQueriesContext(connection) as ctx:
        # code that runs SQL queries
        print(ctx.captured_queries)

Sources:

  • https://blog.ploetzli.ch/2019/showing-sql-queries-with-pytest-and-django/
  • How to force django to print each executed sql query

You can also do the following to get the queries (and then for instance print it or evaluate it in your test).

Actually you shouldn't alter django.conf.settings nowadays, therefore I use override_settings.

from django.db import connection, reset_queries
from django.test import override_settings, TransactionTestCase

class TransactionTests(TransactionTestCase):

    @override_settings(DEBUG=True)
    def test_sql(self):
        reset_queries()
        try:
            # Code that uses the ORM goes here
        except Exception as e:
            pass
        self.assertEqual(connection.queries, [])

TestCase might also be suitable, see the differences in this answer.

See the Django documentation for details for SQL output.