helm_unit_tests.rst

Helm Unit Tests

On the Airflow Project, we have decided to stick with pythonic testing for our Helm chart. This makes our chart easier to test, easier to modify, and able to run with the same testing infrastructure. To add Helm unit tests add them in helm_tests.

class TestBaseChartTest: ...

To render the chart create a YAML string with the nested dictionary of options you wish to test. You can then use our render_chart function to render the object of interest into a testable Python dictionary. Once the chart has been rendered, you can use the render_k8s_object function to create a k8s model object. It simultaneously ensures that the object created properly conforms to the expected resource spec and allows you to use object values instead of nested dictionaries.

Example test here:

from tests.charts.common.helm_template_generator import render_chart, render_k8s_object

git_sync_basic = """
dags:
  gitSync:
  enabled: true
"""


class TestGitSyncScheduler:
    def test_basic(self):
        helm_settings = yaml.safe_load(git_sync_basic)
        res = render_chart(
            "GIT-SYNC",
            helm_settings,
            show_only=["templates/scheduler/scheduler-deployment.yaml"],
        )
        dep: k8s.V1Deployment = render_k8s_object(res[0], k8s.V1Deployment)
        assert "dags" == dep.spec.template.spec.volumes[1].name

To execute all Helm tests using breeze command and utilize parallel pytest tests, you can run the following command (but it takes quite a long time even in a multi-processor machine).

breeze testing helm-tests

You can also execute tests from a selected package only. Tests in tests/chart are grouped by packages so rather than running all tests, you can run only tests from a selected package. For example:

breeze testing helm-tests --test-type basic

Will run all tests from tests-charts/basic package.

You can also run Helm tests individually via the usual breeze command. Just enter breeze and run the tests with pytest as you would do with regular unit tests (you can add -n auto command to run Helm tests in parallel - unlike most of the regular unit tests of ours that require a database, the Helm tests are perfectly safe to be run in parallel (and if you have multiple processors, you can gain significant speedups when using parallel runs):

breeze

This enters breeze container.

pytest helm_tests -n auto

This runs all chart tests using all processors you have available.

pytest helm_tests/test_airflow_common.py -n auto

This will run all tests from tests_airflow_common.py file using all processors you have available.

pytest helm_tests/test_airflow_common.py

This will run all tests from tests_airflow_common.py file sequentially.

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For other kinds of tests look at Testing document