helm-test

Mocha based testing for Helm packages!

What does it do?

Helm is a great tool for packaging and templating your kubernetes definitions. However as your templates grow in complexity, and you start to introduce conditionals and other logic it becomes increasingly easy to unwittingly break them.

I wanted to take some of the tooling that I use when coding, and create a simple cli to test the manifest files that helm generates. helm-test will run helm to generate your manifests and then parse the results into JSON for you to perform assertions against.

How to use it

Installation

helm-test is distributed as a command line interface, simply type npm install -g helm-test. Once you've got that installed, you just need to write some tests.

Writing tests

Tests should be placed in the root of your helm chart, in a tests/ folder like so:

/
  Chart.yaml
  values.yaml
  charts/
  templates/
  tests/
    your-tests.js
    some-more-tests.js

Your test specification follows the popular Mocha layout. You can see an example here

There are some global helper variables defined for use in your tests:

helm

This is the root context and exposes the following functions:

withValueFile(path): Specify a value file to use when running helm, relative to the root of your chart. You can call this multiple times
set(key, value): Allows you to override a specific value, for example set('service.port', '80') would do --set service.port=80 when running helm
go(done): Run a helm template generation and parse the output

yaml

This global helper function allows you to parse yaml using yamljs. This is useful for scenarios like a configmap containing a string block which sub contains yaml, that you wish to assert on.

eg.

const json = yaml.parse(results.ofType('ConfigMap')[0].spec.data);
json.metadata.name.should.eql('some-manifest');

results

After running helm.go, the results variable will be populated, and it exposes the following:

length: The number of manifest files
ofType(type): Get all manifests of a given type

Running your tests

Is a simple as doing helm-test:

❯ helm-test
  helm-test [info] Welcome to helm-test v0.1.6! +0ms
  helm-test [info] Testing... +0ms


  Helm Chart
    ✓ should have three manifests
    The Service
      ✓ should have standard labels
      ✓ should have valid metadata.name
      ✓ should be a LoadBalancer
      ✓ should be on an internal ip
      ✓ should have a single http-web port
      ✓ should select the right pods
    The StatefulSet
      ✓ should have the right name
      ✓ should have standard labels
      ✓ should have a serviceName
      ✓ should have a single replica
      ✓ should be a RollingUpdate strategy
      ✓ should have matching matchLabels and template labels
      Containers
        ✓ should have two containers
        Master
          ✓ should use the right image
          ✓ should limit 2gig of ram
          ✓ should limit 1.8 CPU
          ✓ should have a http-web port
    The ConfigMap
      ✓ should have standard labels
      ✓ should have valid metadata
      ✓ should have a docker-host key


  21 passing (123ms)

  helm-test [info] Complete. +443ms

Constantly running tests and watching for changes

You can have helm-test run every time it detects a change in your chart by simply doing helm-test --watch

cacedo/helm-test