Testing Apps¶

In general apps can be tested like other Django apps. In most cases you'll want to run your automated tests via the nautobot-server test <app_module> command or, if using the coverage Python library, coverage run --module nautobot.core.cli test <app_module>.

Detecting N+1 Query Patterns¶

The AssertNoRepeatedQueries context manager helps detect N+1 query patterns in your tests. It captures all SQL queries executed within the block, normalizes them by stripping literal values to create structural templates, and fails the test if any template repeats more than the specified threshold.

from nautobot.apps.testing import AssertNoRepeatedQueries

class MyTestCase(TestCase):
    def test_list_view_no_n_plus_one(self):
        with AssertNoRepeatedQueries(self, threshold=10):
            self.client.get(reverse("plugins:my_app:widget_list"))

    def test_api_no_n_plus_one(self):
        with AssertNoRepeatedQueries(self, threshold=5):
            response = self.client.get(reverse("plugins-api:my_app-api:widget-list"), **self.header)

Parameters:

test_case - A TestCase instance (typically self).
threshold - Maximum allowed repetitions of any single query template (default: 10).

The context manager normalizes queries by replacing quoted string literals and IN (...) clauses with placeholders, so queries that differ only in their parameter values are counted together. If a violation is detected, the test fails with a message showing the offending query pattern(s), their repetition counts, and the total number of queries.

Factories¶

The TEST_USE_FACTORIES setting defaults to False when testing apps, primarily for backwards-compatibility reasons. It can prove a useful way of populating a baseline of Nautobot database data for your tests and save you the trouble of creating a large amount of baseline data yourself. We recommend adding factory-boy to your app's development dependencies and settings TEST_USE_FACTORIES = True in your app's development/test nautobot_config.py to take advantage of this.