Chart Tests

A chart contains a number of Kubernetes resources and components that worktogether. As a chart author, you may want to write some tests that validate thatyour chart works as expected when it is installed. These tests also help thechart consumer understand what your chart is supposed to do.

A test in a helm chart lives under the templates/ directory and is a poddefinition that specifies a container with a given command to run. The containershould exit successfully (exit 0) for a test to be considered a success. The poddefinition must contain one of the helm test hook annotations: helm.sh/hook:test-success or helm.sh/hook: test-failure.

Example tests:- Validate that your configuration from the values.yaml file was properlyinjected.- Make sure your username and password work correctly- Make sure an incorrect username and password does not work- Assert that your services are up and correctly load balancing- etc.

You can run the pre-defined tests in Helm on a release using the command helmtest <RELEASE_NAME>. For a chart consumer, this is a great way to sanity checkthat their release of a chart (or application) works as expected.

A Breakdown of the Helm Test Hooks

In Helm, there are two test hooks: test-success and test-failure

test-success indicates that test pod should complete successfully. In otherwords, the containers in the pod should exit 0. test-failure is a way toassert that a test pod should not complete successfully. If the containers inthe pod do not exit 0, that indicates success.

Example Test

Here is an example of a helm test pod definition in an example mariadb chart:

  1. mariadb/
  2.   Chart.yaml
  3.   README.md
  4.   values.yaml
  5.   charts/
  6.   templates/
  7.   templates/tests/test-mariadb-connection.yaml

In wordpress/templates/tests/test-mariadb-connection.yaml:

  1. apiVersion: v1
  2. kind: Pod
  3. metadata:
  4.   name: "{{ .Release.Name }}-credentials-test"
  5.   annotations:
  6.     "helm.sh/hook": test-success
  7. spec:
  8.   containers:
  9.   - name: {{ .Release.Name }}-credentials-test
  10.     image: {{ .Values.image }}
  11.     env:
  12.       - name: MARIADB_HOST
  13.         value: {{ template "mariadb.fullname" . }}
  14.       - name: MARIADB_PORT
  15.         value: "3306"
  16.       - name: WORDPRESS_DATABASE_NAME
  17.         value: {{ default "" .Values.mariadb.mariadbDatabase | quote }}
  18.       - name: WORDPRESS_DATABASE_USER
  19.         value: {{ default "" .Values.mariadb.mariadbUser | quote }}
  20.       - name: WORDPRESS_DATABASE_PASSWORD
  21.         valueFrom:
  22.           secretKeyRef:
  23.             name: {{ template "mariadb.fullname" . }}
  24.             key: mariadb-password
  25.     command: ["sh", "-c", "mysql --host=$MARIADB_HOST --port=$MARIADB_PORT --user=$WORDPRESS_DATABASE_USER --password=$WORDPRESS_DATABASE_PASSWORD"]
  26.   restartPolicy: Never

Steps to Run a Test Suite on a Release

  • $ helm install mariadb
  1. NAME:   quirky-walrus
  2. LAST DEPLOYED: Mon Feb 13 13:50:43 2017
  3. NAMESPACE: default
  4. STATUS: DEPLOYED
  • $ helm test quirky-walrus
  1. RUNNING: quirky-walrus-credentials-test
  2. SUCCESS: quirky-walrus-credentials-test

Notes

  • You can define as many tests as you would like in a single yaml file or spreadacross several yaml files in the templates/ directory
  • You are welcome to nest your test suite under a tests/ directory like<chart-name>/templates/tests/ for more isolation