helm snapshot

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

Documentation

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

• Install
• Get Started
• Test Suite File
• Usage
  • Flags
• Example
• Snapshot Testing
• Related Projects / Commands
• Contributing

Install

$ helm plugin install https://github.com/bdun1013/helm-snapshot

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

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

Check DOCUMENT for more details about writing tests.

Usage

$ helm snapshot [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
-f, --file stringArray   glob paths of test files location, default to tests/*_test.yaml (default [tests/*_test.yaml])
-h, --help               help for snapshot
-u, --update-snapshot    update the snapshot cached if needed, make sure you review the change before update

Example

Check __fixtures__/basic/ for some basic use cases of a simple chart.

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 snapshot -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.

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:

# parent-chart/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 __fixtures__/with-subchart/ as an example.

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.

License

MIT

Contributing

Issues and PRs are welcome!
Before start developing this plugin, you must have go and dep installed, and run:

git clone git@github.com:lrills/helm-snapshot.git
cd helm-snapshot
dep ensure

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

• dep status passed. Make sure you run dep ensure if new dependencies added.
• gofmt no changes needed. Please run gofmt -w -s before you commit.
• go test ./snapshot/... 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 ./snapshot/...

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