Testing Nautobot¶

Best practices for developing and maintaining Nautobot's automated unit/integration test suites.

Unit tests are automated tests written and run to ensure that a section of the Nautobot application (known as the "unit") meets its design and behaves as intended and expected. Most commonly as a developer of or contributor to Nautobot you will be writing unit tests to exercise the code you have written. Unit tests are not meant to test how the application behaves, only the individual blocks of code, therefore use of mock data and phony connections is common in unit test code. As a guiding principle, unit tests should be fast, because they will be executed quite often.

Integration tests are automated tests written and run to ensure that the Nautobot application behaves as expected when being used as it would be in practice. By contrast to unit tests, where individual units of code are being tested, integration tests rely upon the server code actually running, and web UI clients or API clients to make real connections to the service to exercise actual workflows, such as navigating to the login page, filling out the username/passwords fields, and clicking the "Log In" button.

Integration testing is much more involved, and builds on top of the foundation laid by unit testing. As a guiding principle, integration tests should be comprehensive, because they are the last mile to asserting that Nautobot does what it is advertised to do. Without integration testing, we have to do it all manually, and that's no fun for anyone!

Tagging Tests¶

By Nautobot convention, unit tests must be tagged with unit. The base test case class nautobot.core.testing.TestCase has this tag, therefore any test cases inheriting from that class do not need to be explicitly tagged. All existing view and API test cases in the Nautobot test suite inherit from this class.

By Nautobot convention, integration tests must be tagged with integration. The base test case class nautobot.core.testing.integration.SeleniumTestCase has this tag, therefore any test cases inheriting from that class do not need to be explicitly tagged. All existing integration test cases in the Nautobot test suite inherit from this class.

Changed in version 2.0.0

The base test classes moved from nautobot.utilities.testing to nautobot.core.testing.

The invoke unittest and invoke integration-test commands are intentionally distinct, and the correct tagging of test cases is essential to enforcing the division between these two test categories. We never want to risk running the unit tests and integration tests at the same time. The isolation from each other is critical to a clean and manageable continuous development cycle.

Base Classes and Code Location¶

Test Type	Base Class	Code Location
Unit	`nautobot.core.testing.TestCase` or subclass (see below)	`nautobot/APP/tests/test_*.py`
Integration	`nautobot.core.testing.integration.SeleniumTestCase`	`nautobot/APP/tests/integration/test_*.py`

New unit tests must always inherit from nautobot.core.testing.TestCase or one of its subclasses. Do not use django.test.TestCase.
- API view test cases should generally inherit from one or more of the classes in nautobot.core.testing.api.APIViewTestCases.
- Filterset test cases should generally inherit from nautobot.core.testing.filters.FilterTestCases.FilterTestCase.
- Model test cases should generally inherit from nautobot.core.testing.models.ModelTestCases.BaseModelTestCase.
- View test cases should generally inherit from one or more of the classes in nautobot.core.testing.views.ViewTestCases.
New integration tests must always inherit from nautobot.core.testing.integration.SeleniumTestCase. Do not use any other base class for integration tests.

Changed in version 2.0.0

The base test classes moved from nautobot.utilities.testing to nautobot.core.testing.

Generic Filter Tests¶

Added in version 2.0.0

Nautobot provides a set of generic tests for testing the behavior of FilterSets. These tests are located in nautobot.core.testing.filters.FilterTestCase and can be used to test some common filters in Nautobot.

Generic Boolean Filter Tests¶

When using FilterTestCase, all filters that are instances of nautobot.core.filters.RelatedMembershipBooleanFilter that are not using a custom filter method will be tested to verify that the filter returns the same results as the model's queryset. RelatedMembershipBooleanFilter filters will be tested for both True and False values.

Generic Multiple Choice Filter Tests¶

A generic_filter_tests attribute with a list of filters can be defined on the test class to run generic tests against multiple choice filters. The generic_filter_tests attribute should be in the following format:

generic_filter_tests = (
    # use a single item when the filter name matches the model field name
    ["model_field"],
    # use [filter_name, field_name] when the filter name does not match the model field name
    ["related_object_filter", "related_object__name"],
    # the field name is passed as a kwarg to the `queryset.filter` method, so the dunder syntax can be used to make nested queries
    ["related_object_filter", "related_object__id"],
)

Tags Filter Test¶

If the model being tested is a PrimaryModel, the tags filter will be automatically tested by passing at least two values to the filter and verifying that the result matches the equivalent queryset filter.

Integration Tests¶

Troubleshooting Integration Tests¶

Because integration tests normally involve interacting with Nautobot through a browser via Selenium and the Splinter wrapper library, they can be difficult to troubleshoot directly from the Python code when a failure occurs. A common troubleshooting technique is to add a breakpoint() at the appropriate place in the Python test code (i.e., immediately prior to the observed failure). When the breakpoint is hit and the test pauses, you can then use a VNC viewer application (such as macOS's "Screen Sharing" app) to connect to the running Selenium instance (localhost:15900 if using the Docker development environment; the default password if prompted is simply "secret"). This will allow you to interact live with the testing web browser in its current state and can often provide invaluable insight into the nature of any test failure.

Factories¶

Added in version 1.5.0

Nautobot uses the factory_boy library as a way to generate randomized but plausible database data for use in unit and integration tests, or for convenience in populating a local development instance.

Factories for each Nautobot app's models are defined in the corresponding nautobot/APPNAME/factory.py files. Helper classes and functions for certain common patterns are defined in nautobot/core/factory.py. Factories can be used directly from nautobot-server nbshell so long as you have factory_boy installed. Examples:

>>> from nautobot.tenancy.factory import TenantFactory, TenantGroupFactory
>>> # Create a single TenantGroup instance
>>> TenantGroupFactory.create()
<TenantGroup: Peterson, Nunez and Miller>
>>> # Create 5 Tenant instances
>>> TenantFactory.create_batch(5)
[<Tenant: Smith-Vance>, <Tenant: Sanchez, Brown and Davis>, <Tenant: Benson and Sons>, <Tenant: Pennington PLC>, <Tenant: Perez and Sons>]
>>> # Create 5 more Tenant instances all with a specified "group" value
>>> TenantFactory.create_batch(5, group=TenantGroup.objects.first())
[<Tenant: Mercado, Wilson and Fuller>, <Tenant: Blackburn-Andrade>, <Tenant: Oliver-Ramirez>, <Tenant: Pugh-Clay>, <Tenant: Norman and Sons>]

Warning

factory_boy is only a development dependency of Nautobot. You cannot use the model factories in a production deployment of Nautobot unless you directly pip install factory_boy into such a deployment.

Nautobot's custom test runner class (nautobot.core.tests.runner.NautobotTestRunner) makes use of the various factories to pre-populate the test database with data before running any tests. This reduces the need for individual tests to define their own baseline data sets.

Info

Because plugins also commonly use Nautobot's test runner, the base Nautobot settings.py currently defaults TEST_USE_FACTORIES to False so as to not negatively impact plugin tests that may not be designed to account for the presence of pre-populated test data in the database. This configuration is overridden to True in nautobot/core/tests/nautobot_config.py for Nautobot's own tests.

Factory Caching¶

Added in version 1.5.11

To reduce the time taken between multiple test runs, a new argument has been added to the nautobot-server test, invoke unittest and invoke integration-test commands: --cache-test-fixtures. When running one of these commands with --cache-test-fixtures for the first time, after the factory data has been generated it will be saved to a factory_dump.json file in the development directory. On subsequent runs of unit or integration tests, the factory data will be loaded from the file instead of being generated again. This can significantly reduce the time taken to run tests. It's a good idea to let this file be regenerated after pulling new code from the repository, as the factory data may have changed.

Factory caching is disabled by default. When using the invoke commands to run tests, caching can be enabled by default for your development environment by setting the cache_test_fixtures key to True in the invoke.yml file.

Performance Tests¶

Added in version 1.5.0

Running Performance Tests¶

Nautobot uses django-slowtests to run performance tests. To run performance tests, you need to install the django-slowtests package. Once you install the package, you can do invoke performance-test or invoke unittest --performance-test to run unit tests with NautobotPerformanceTestRunner. The invoke commands will automatically add --testrunner nautobot.core.tests.runner.NautobotPerformanceTestRunner to the coverage run command and this flag will replace the default NautobotTestRunner while retaining all its functionalities with the addition of performance evaluation after test runs.

NautobotPerformanceTestRunner which inherits from DiscoverSlowestTestsRunner will only be available when django-slowtests is installed. The runner measures the time to run unit tests against baselines stored in a designated .yml file (defaults to nautobot/core/tests/performance_baselines.yml) in addition to running the unit tests themselves.

Warning

This functionality requires the installation of the django-slowtests Python package, which is present in Nautobot's own development environment, but is not an inherent dependency of the Nautobot package when installed otherwise, such as into a plugin's development environment.

Info

invoke performance-test is enabled when django-slowtests is installed and when called, it will run and evaluate the performance of specific unit tests that are tagged with performance i.e. @tag("performance"). invoke unittest --performance-report and invoke integration-test --performance-report will also be enabled and when called, they will generate a performance report for all the tests ran in the terminal. If performance baselines for tests are not available:

175 abnormally slower tests:
Performance baseline for test_account (nautobot.circuits.tests.test_filters.ProviderTestCase) is not available. Test took 0.0758s to run
Performance baseline for test_asn (nautobot.circuits.tests.test_filters.ProviderTestCase) is not available. Test took 0.0427s to run
Performance baseline for test_bulk_create_objects (nautobot.circuits.tests.test_api.CircuitTerminationTest) is not available. Test took 0.2900s to run
Performance baseline for test_bulk_create_objects (nautobot.circuits.tests.test_api.CircuitTest) is not available. Test took 0.2292s to run
Performance baseline for test_bulk_create_objects (nautobot.circuits.tests.test_api.CircuitTypeTest) is not available. Test took 0.1596s to run
Performance baseline for test_bulk_create_objects (nautobot.circuits.tests.test_api.ProviderNetworkTest) is not available. Test took 0.1897s to run
Performance baseline for test_bulk_create_objects (nautobot.circuits.tests.test_api.ProviderTest) is not available. Test took 0.2092s to run
Performance baseline for test_bulk_delete_objects (nautobot.circuits.tests.test_api.CircuitTerminationTest) is not available. Test took 0.1168s to run
Performance baseline for test_bulk_delete_objects (nautobot.circuits.tests.test_api.CircuitTest) is not available. Test took 0.2762s to run
Performance baseline for test_bulk_delete_objects (nautobot.circuits.tests.test_api.CircuitTypeTest) is not available. Test took 0.0663s to run
Performance baseline for test_bulk_delete_objects (nautobot.circuits.tests.test_api.ProviderNetworkTest) is not available. Test took 0.0875s to run
...

Info

If performance baselines for tests are available and the time it take to run tests are siginificantly slower than baselines:

12 abnormally slower tests:
0.9838s test_bulk_import_objects_with_constrained_permission (nautobot.ipam.tests.test_views.VLANTestCase) is significantly slower than the baseline 0.3692s
1.2548s test_create_multiple_objects_with_constrained_permission (nautobot.dcim.tests.test_views.ConsolePortTestCase) is significantly slower than the baseline 0.5385s
1.4289s test_create_multiple_objects_with_constrained_permission (nautobot.dcim.tests.test_views.DeviceBayTestCase) is significantly slower than the baseline 0.5616s
1.1551s test_create_multiple_objects_with_constrained_permission (nautobot.dcim.tests.test_views.InventoryItemTestCase) is significantly slower than the baseline 0.5822s
1.4712s test_create_multiple_objects_with_constrained_permission (nautobot.dcim.tests.test_views.RearPortTestCase) is significantly slower than the baseline 0.5695s
1.5958s test_create_multiple_objects_with_constrained_permission (nautobot.virtualization.tests.test_views.VMInterfaceTestCase) is significantly slower than the baseline 1.0020s
1.0566s test_create_object_with_constrained_permission (nautobot.virtualization.tests.test_views.VirtualMachineTestCase) is significantly slower than the baseline 0.3627s
...

Info

To output the performance evaluation to a file for later use, i.e. as performance baselines for future test runs, do invoke performance-test --performance-snapshot. This command will collect the names of the test and their execution_time and store them in a .yml file default to report.yml. Subsequently, the data in that file will have to be manually added to the baseline file set at TEST_PERFORMANCE_BASELINE_FILE to be used as baselines in performance tests.

Example output of invoke performance-test --performance-snapshot:

- tests:
  - name: test_account (nautobot.circuits.tests.test_filters.ProviderTestCase)
    execution_time: 0.07075
  - name: test_asn (nautobot.circuits.tests.test_filters.ProviderTestCase)
    execution_time: 0.041262
  - name: test_cabled (nautobot.circuits.tests.test_filters.CircuitTerminationTestCase)
    execution_time: 0.268673
  - name: test_cid (nautobot.circuits.tests.test_filters.CircuitTestCase)
    execution_time: 0.116057
  - name: test_circuit_id (nautobot.circuits.tests.test_filters.CircuitTerminationTestCase)
    execution_time: 0.042665
  - name: test_commit_rate (nautobot.circuits.tests.test_filters.CircuitTestCase)
    execution_time: 0.047894
  - name: test_connected (nautobot.circuits.tests.test_filters.CircuitTerminationTestCase)
    execution_time: 0.056196
  - name: test_id (nautobot.circuits.tests.test_filters.CircuitTerminationTestCase)
    execution_time: 0.03598
...

Gathering Performance Test Baseline Data¶

TEST_PERFORMANCE_BASELINE_FILE specifies the file in which performance baselines are stored, defaults to nautobot/core/tests/performance_baselines.yml. Currently, only baselines for those unit tests tagged with performance are stored.

You can add baselines for your own test to nautobot/core/tests/performance_baselines.yml or have your own baseline yaml file for performance testing by specifying a different file path for TEST_PERFORMANCE_BASELINE_FILE in plugin's development/test nautobot_config.py, and store the output of invoke performance-test --performance-snapshot in that file. --performance-snapshot flag will store the results of your performance test to a new report.yml and all you need to do is copy/paste the results to the file set by TEST_PERFORMANCE_BASELINE_FILE. Now you have baselines for your own tests!

Example output of invoke performance-test --performance-snapshot:

- tests:
  - name: test_account (nautobot.circuits.tests.test_filters.ProviderTestCase)
    execution_time: 0.07075
  - name: test_asn (nautobot.circuits.tests.test_filters.ProviderTestCase)
    execution_time: 0.041262
  - name: test_cabled (nautobot.circuits.tests.test_filters.CircuitTerminationTestCase)
    execution_time: 0.268673
  - name: test_cid (nautobot.circuits.tests.test_filters.CircuitTestCase)
    execution_time: 0.116057
  - name: test_circuit_id (nautobot.circuits.tests.test_filters.CircuitTerminationTestCase)
...

if you decide to run invoke unittest --performance-test which will run tests that currently do not have their baselines present in the file, your output could look something like this:

175 abnormally slower tests:
Performance baseline for test_account (nautobot.circuits.tests.test_filters.ProviderTestCase) is not available. Test took 0.0758s to run
Performance baseline for test_asn (nautobot.circuits.tests.test_filters.ProviderTestCase) is not available. Test took 0.0427s to run
Performance baseline for test_bulk_create_objects (nautobot.circuits.tests.test_api.CircuitTerminationTest) is not available. Test took 0.2900s to run
Performance baseline for test_bulk_create_objects (nautobot.circuits.tests.test_api.CircuitTest) is not available. Test took 0.2292s to run
Performance baseline for test_bulk_create_objects (nautobot.circuits.tests.test_api.CircuitTypeTest) is not available. Test took 0.1596s to run
Performance baseline for test_bulk_create_objects (nautobot.circuits.tests.test_api.ProviderNetworkTest) is not available. Test took 0.1897s to run
Performance baseline for test_bulk_create_objects (nautobot.circuits.tests.test_api.ProviderTest) is not available. Test took 0.2092s to run
Performance baseline for test_bulk_delete_objects (nautobot.circuits.tests.test_api.CircuitTerminationTest) is not available. Test took 0.1168s to run
Performance baseline for test_bulk_delete_objects (nautobot.circuits.tests.test_api.CircuitTest) is not available. Test took 0.2762s to run
Performance baseline for test_bulk_delete_objects (nautobot.circuits.tests.test_api.CircuitTypeTest) is not available. Test took 0.0663s to run
Performance baseline for test_bulk_delete_objects (nautobot.circuits.tests.test_api.ProviderNetworkTest) is not available. Test took 0.0875s to run
...

Caveats¶

Warning

django-slowtests is only a development dependency of Nautobot. You cannot run performance tests in a production deployment of Nautobot unless you directly pip install django-slowtests into such a deployment.

Info

Because plugins also commonly use Nautobot's default test runner NautobotTestRunner, in order to use NautobotPerformanceTestRunner you need to add django-slowtests as a part of your plugin dev dependencies.

Test Code Style¶

Use more specific/feature-rich test assertion methods where available (e.g. self.assertInHTML(fragment, html) rather than self.assertTrue(re.search(fragment, html)) or assert re.search(fragment, html) is not None).
Keep test case scope (especially in unit tests) small. Split test functions into smaller tests where possible; otherwise, use self.subTest() to delineate test blocks as appropriate.