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helm unittest

Since the end of January 2023, a new version of the unittest plugin is published in the main repository helm-unittest/helm-unittest.

Unit test for helm chart in YAML to keep your chart consistent and robust!

Feature:

• write test file in pure YAML
• render locally with no need of tiller
• create nothing on your cluster
• define values and release options
• snapshot testing
• test suite code completion and validation

Documentation

If you are ready for writing tests, check the DOCUMENT for the test API in YAML.

• Install
• Docker Usage
• Get Started
• Test Suite File
• Usage
  • Flags
• Example
• Snapshot Testing
• Dependent subchart Testing
• Tests within subchart
• test suite code completion and validation
• Frequently Asked Questions
• Related Projects / Commands
• Contributing

Install

$ helm plugin install https://github.com/quintush/helm-unittest

It will install the latest version of binary into helm plugin directory.

The latest version will point to latest version of helm-unittest/helm-unittest.

Docker Usage

# run help of latest helm with latest helm unittest plugin
docker run -ti --rm -v $(pwd):/apps quintush/helm-unittest

# run help of specific helm version with specific helm unittest plugin version
docker run -ti --rm -v $(pwd):/apps quintush/helm-unittest:3.3.0-0.2.2

# run unittests of a helm 2 chart
# make sure to mount local folder to /apps in container
docker run -ti --rm -v $(pwd):/apps quintush/helm-unittest:2.16.10-0.2.2 .

# run unittests of a helm 3 chart
# make sure to mount local folder to /apps in container
docker run -ti --rm -v $(pwd):/apps quintush/helm-unittest:3.3.0-0.2.2 -3 .

# run unittests of a helm 3 chart with Junit output for CI validation
# make sure to mount local folder to /apps in container
# the test-output.xml will be available in the local folder.
docker run -ti --rm -v $(pwd):/apps quintush/helm-unittest:3.3.0-0.2.2 -3 -o test-output.xml -t junit .

The docker container contains the fully installed helm client, including the helm-unittest plugin.

Get Started

Add tests in .helmignore of your chart, and create the following test file at $YOUR_CHART/tests/deployment_test.yaml:

suite: test deployment
templates:
  - deployment.yaml
tests:
  - it: should work
    set:
      image.tag: latest
    asserts:
      - isKind:
          of: Deployment
      - matchRegex:
          path: metadata.name
          pattern: -my-chart$
      - equal:
          path: spec.template.spec.containers[0].image
          value: nginx:latest

and run:

$ helm unittest $YOUR_CHART

Now there is your first test! ;)

Test Suite File

The test suite file is written in pure YAML, and default placed under the tests/ directory of the chart with suffix _test.yaml. You can also have your own suite files arrangement with -f, --file option of cli set as the glob patterns of test suite files related to chart directory, like:

$ helm unittest -f 'my-tests/*.yaml' -f 'more-tests/*.yaml' my-chart

Check DOCUMENT for more details about writing tests.

Usage

$ helm unittest [flags] CHART [...]

This renders your charts locally (without tiller) and runs tests defined in test suite files.

Flags

      --color                  enforce printing colored output even stdout is not a tty. Set to false to disable color
      --strict                 strict parse the testsuites (default false)
  -v, --values stringArray     absolute or glob paths of values files location, default no values files
  -f, --file stringArray       glob paths of test files location, default to tests\*_test.yaml (default [tests\*_test.yaml])
  -3, --helm3                  parse helm charts as helm3 charts (default false)
  -q, --failfast               direct quit testing, when a test is failed (default false)
  -h, --help                   help for unittest
  -t, --output-type string     the file-format where testresults are written in, accepted types are (JUnit, NUnit, XUnit) (default XUnit)
  -o, --output-file string     the file where testresults are written in format specified, defaults no output is written to file
  -u, --update-snapshot        update the snapshot cached if needed, make sure you review the change before update
  -s, --with-subchart charts   include tests of the subcharts within charts folder (default true)

Example

Check test/data/v2/basic/ for some basic use cases of a simple chart (version < 2). Check test/data/v3/basic/ for some basic use cases of a simple chart (version > 3).

Snapshot Testing

Sometimes you may just want to keep the rendered manifest not changed between changes without every details asserted. That's the reason for snapshot testing! Check the tests below:

templates:
  - deployment.yaml
tests:
  - it: pod spec should match snapshot
    asserts:
      - matchSnapshot:
          path: spec.template.spec
  # or you can snapshot the whole manifest
  - it: manifest should match snapshot
    asserts:
      - matchSnapshot: {}

The matchSnapshot assertion validate the content rendered the same as cached last time. It fails if the content changed, and you should check and update the cache with -u, --update-snapshot option of cli.

$ helm unittest -u my-chart

The cache files is stored as __snapshot__/*_test.yaml.snap at the directory your test file placed, you should add them in version control with your chart.

Dependent subchart Testing

If you have dependent subcharts (installed via helm dependency) existed in charts directory (they don't need to be extracted), it is possible to unittest these from the root chart. This feature can be helpfull to validate if good default values are accidently overwritten within your default helm chart.

# $YOUR_CHART/tests/xxx_test.yaml
templates:
  - charts/postgresql/templates/xxx.yaml
tests:
  - it:
    set:
      # this time required to prefix with "postgresql."
      postgresql.somevalue: should_be_scoped
    asserts:
      - ...

Note 1: if dependent subcharts uses an alias, use the alias name in the templates. Note 2: using the folder structure in templates can also be used to unittest templates which are placed in subfolders or unittest subcharts from the rootchart.

Check test/data/v2/with-subchart/ or test/data/v3/with-subchart/ as an example.

Tests within subchart

If you have customized subchart (not installed via helm dependency) existed in charts directory, tests inside would also be executed by default. You can disable this behavior by setting --with-subchart=false flag in cli, thus only the tests in root chart will be executed. Notice that the values defined in subchart tests will be automatically scoped, you don't have to add dependency scope yourself:

# with-subchart/charts/child-chart/tests/xxx_test.yaml
templates:
  - xxx.yaml
tests:
  - it:
    set:
      # no need to prefix with "child-chart."
      somevalue: should_be_scoped
    asserts:
      - ...

Check test/data/v2/with-subchart/ or test/data/v3/with-subchart/ as an example.

Test Suite code completion and validation

Most popular IDEs (IntelliJ, Visual Studio Code, etc.) support applying schemas to YAML files using a JSON Schema. This provides comprehensive documentation as well as code completion while editing the test-suite file:

In addition, test-suite files can be validated while editing so wrongfully added additional properties or incorrect data types can be detected while editing:

Visual Studio Code

When developing with VSCode, the very popular YAML plug-in (created by RedHat) allows adding references to schemas by adding a comment line on top of the file:

# yaml-language-server: $schema=https://raw.githubusercontent.com/quintush/helm-unittest/master/schema/helm-testsuite.json
suite: http-service.configmap_test.yaml
templates: [configmap.yaml]
release:
  name: test-release
  namespace: TEST_NAMESPACE

Alternatively, you can add the schema globally to the IDE, using a well defined pattern:

"yaml.schemas": {
  "https://raw.githubusercontent.com/quintush/helm-unittest/master/schema/helm-testsuite.json": ["charts/*/tests/*_test.yaml"]
}

IntelliJ

Similar to VSCode, IntelliJ allows mapping file patterns to schemas via preferences: Languages & Frameworks -> Schemas and DTDs -> JSON Schema Mappings

Frequently Asked Questions

As more people use the unittest plugin, more questions will come. Therefore a Frequently Asked Question page is created to answer the most common questions.

If you are missing an anwer to a question feel free to raise a ticket.

Related Projects / Commands

This plugin is inspired by helm-template, and the idea of snapshot testing and some printing format comes from jest.

And there are some other helm commands you might want to use:

• helm template: render the chart and print the output.

• helm lint: examines a chart for possible issues, useful to validate chart dependencies.

• helm test: test a release with testing pod defined in chart. Note this does create resources on your cluster to verify if your release is correct. Check the doc.

Alternatively, you can also use generic tests frameworks:

• Python

• Go - terratest

License

MIT

Contributing

Issues and PRs are welcome!
Before start developing this plugin, you must have [go] (https://golang.org/doc/install) >= 1.18 installed, and run:

git clone git@github.com:quintush/helm-unittest.git
cd helm-unittest

And please make CI passed when request a PR which would check following things:

• gofmt no changes needed. Please run gofmt -w -s . before you commit.
• go test ./unittest/... passed.

In some cases you might need to manually fix the tests in *_test.go. If the snapshot tests (of the plugin's test code) failed you need to run:

UPDATE_SNAPSHOTS=true go test ./...

This update the snapshot cache file and please add them before you commit.