Knative Reconciler Test

This repo contains tools and frameworks to help validate and test reconciler implementations.

Knative End-to-End and Conformance Testing Framework

We have developed a lightweight testing framework to compose and share Kubernetes cluster based tests for Knative. These tests are intended to be vendor-able by other downstream components, which is useful for Conformance tests and e2e testing for behaviors.

The testing framework is broken into two main components: Features: the small composable steps intended to validate a function or feature, and the Test Environment: which is highly dependent on the cluster, and the config that was passed. The two components are intended to be fairly independent.

A feature is a contained test with phases. A feature could be anything from a set of assertions, to waiting for or validating a condition, installing test dependencies, or interacting with an API. One or more features are tested in an Environment. One or more Environments are produced for test run.

Getting Started

We will compose our test integration into two parts: 1) test entry points, and 2) features.

Test Entry Points

Test entry points are the methods go sees when running go test ./... This includes TestMain and every function with a signature of func Test<Name>(t *testing.T). Because we do not want to run these integration style tests when running unit tests, we will tag the entry point files with // +build e2e

TestMain is where the GlobalEnvironment is created. This global variable will be used for the rest of the test run, it is a singleton.

main_test.go

// +build e2e

import (
	"knative.dev/pkg/injection"
	"knative.dev/reconciler-test/pkg/logging"
	"knative.dev/reconciler-test/pkg/environment"
)

// global is the singleton instance of GlobalEnvironment. It is used to parse
// the testing config for the test run. The config will specify the cluster
// config as well as the parsing level and state flags.
var global environment.GlobalEnvironment

// TestMain is the first entry point for `go test`.
func TestMain(m *testing.M) {
	// environment.InitFlags registers state, level and feature filter flags.
	environment.InitFlags(flag.CommandLine)

	// We get a chance to parse flags to include the framework flags for the
	// framework as well as any additional flags included in the integration.
	flag.Parse()

	// EnableInjectionOrDie will enable client injection, this is used by the
	// testing framework for namespace management, and could be leveraged by
	// features to pull Kubernetes clients or the test environment out of the
	// context passed in the features.
	ctx, startInformers := injection.EnableInjectionOrDie(
		logging.WithTestLogger(nil), nil) // nolint
	startInformers()

	// global is used to make instances of Environments, NewGlobalEnvironment
	// is passing and saving the client injection enabled context for use later.
	global = environment.NewGlobalEnvironment(ctx)

	// Run the tests.
	os.Exit(m.Run())
}

From the instance of GlobalEnvironment, we will test features on an instance of the environment.

// +build e2e

// TestFoo is an example simple test.
func TestFoo(t *testing.T) {
	// Signal to the go test framework that this test can be run in parallel
	// with other tests.
	t.Parallel()

	// Create an instance of an environment. The environment will be configured
	// with any relevant configuration and settings based on the global
	// environment settings. Using environment.Managed(t) will call env.Finish()
	// on test completion. If this option is not used, the test should call
	// env.Finish() to perform cleanup at the end of the test. Additional options
	// can be passed to Environment() if customization is required.
	ctx, env := global.Environment(environment.Managed(t) /*, optional environment options */)

	// With the instance of an Environment, perform one or more calls to Test().
	// Note: env.Test() is blocking until the feature completes.
	env.Test(ctx, t, FooFeature1())
	env.Test(ctx, t, FooFeature2())
}

The role of the Test<Name> methods is to control which features are tested on environment instances. It is your responsibility to understand if it is safe to run multiple features in an environment instance. It is reasonable to pass additional configurations to the feature constructor, unless it is data that should be pulled from the instance of env, which will be talked about in the next Features section.

Test Entry point files should be named "_test.go" and should be tagged e2e or some other meaningful tag that will prevent them from being run on un-excluded go test ./... invocations.

Features

Features are a series of steps that perform actions or validations. Each step is similar to a unit test. It has a scoped objective, and if written with care, a step can be composed and shared in downstream features.

Features have several phases that can be registered, each phase is executed in order, but there are no order guarantees for steps in the same phase. If strict ordering is required it is recommended to break that into an independent feature that is tested on an environment in order required.

Features have 4 phases (timing) on which steps can be composed: Setup, Requirement, Assert, and Teardown. The step functions run in that order.

• Setup is used to install required components or configuration in the environment.
• Requirement is used to validate the cluster, environment, or anything else. Think of this as a preflight validation for the assertions. This can be used as a fast-fail for a feature test before running assert phase steps.
• Assert should assume the namespace is ready to perform or validate the test.
• Teardown should be used to do final feature cleanup, if needed. There is also automatic cleanup of resources and namespace for the environment.

Asserts have two additional properties that allow for filtering from within environment.Test, State and Level.

State represents how mature the requirement is for the feature, we support Alpha, Beta, and Stable.

Level relates to the spec language this test represents, we support Must, MustNot, Should, ShouldNot, and May.

States and Levels are used to filter feature steps based on test parameters.

Features should be in a file with the naming pattern "_feature.go", with no build tag on this file.

Composing Features

A feature.Feature is implemented as a builder pattern. Start with a new feature.Feature:

f := &feature.Feature{Name: "Meaningful Name"}

Then, add steps for each timing as required for the test:

f.Requirement("a cluster requirement is tested", HasClusterRequirement())

f.Setup("install a dependency", InstallADependency(opts))
f.Requirement("a dependency went ready", ADependencyIsReady())

f.Alpha("some experimental feature name").
	Must("does a thing", AssertThing(opts)).
    May("could do another thing", AssertAnotherThing)

f.Beta("pretty sure this is a good feature name").
	Must("does another thing", AssertAnotherThing(opts)).
		Should("please do thing", AssertPleaseDoThing(1, 2, 3))

f.Teardown("remove a dependency", DeleteADependency(opts))

The step functions all have the same function signature,

func AssertSomething(ctx context.Context, t *testing.T) {
	// TODO: some assert.
}

Step functions could return a feature.StepFn, allowing options or configuration to be passed to the StepFn. For example, AssertDelivery:

func AssertDelivery(to string, count int, interval, timeout time.Duration) feature.StepFn {
	return func(ctx context.Context, t *testing.T) {
		// TODO: some assert.
	}
}

The context passed to a StepFn is client injection enabled, and decorated with environment context (and extendable based on passing opts callbacks in global.Environment(opts EnvOpts...)).

In addition to the normal client injection typedclient.Get(ctx) methods, there is

env := environment.FromContext(ctx)

This returns the Environment the feature is being tested in.

Feature Sets

Sometimes it makes sense to be able to provide a set of Features all at once. We call these "Feature Sets". They are intended to allow upstreams to bundle sets of features together to provide a simple low code way to vendor and run a collection of Features together. Test and TestSet can be used together on an environment.

ctx, env := global.Environment(environment.Managed(t) /*, optional environment options */)

// With the instance of an Environment, perform one or more calls to Test().
env.Test(ctx, t, FooFeature1())
// Note: env.TestSet() is blocking until all features complete.
env.TestSet(ctx, t, FooFeatureSet1())

Composing Feature Sets

A feature.FeatureSet is implemented as a simple wrapper for a list of feature.Features, with a name for context.

fs := &feature.FeatureSet{
	Name:     "Some higher order idea",
	Features: []feature.Feature{
		*OneAspectFeature(),
		*AnotherAspectFeature(),
		*OptionalAspectFeature(),
	},
}

YAML Setup Helpers

The testing framework also enables YAML based installing of components. This framework can help:

1. produce go-based test images via ko publish.
2. discover ko-based packages in local YAML file.
3. apply local YAML files with some light go templating to the test environment.

To produce images, register an interest in one or more packages with the environment package in an init method.

import "knative.dev/reconciler-test/pkg/environment"

func init() {
	environment.RegisterPackage("example.com/some/local/package", "example.com/another/package")
}

This can be discovered dynamically by the helper function to scan embedded filesystem YAML files for ko:// images, manifest.ImagesFromFS(fs)

import (
	"knative.dev/reconciler-test/pkg/environment"
	"knative.dev/reconciler-test/pkg/manifest"
)
//go:embed job.yaml
var jobTemplate embed.FS

func init() {
	environment.RegisterPackage(manifest.ImagesFromFS(jobTemplate)...)
}

Images registered with the environment package will be produced on the first call to environment.ProduceImages(), which happens as a byproduct of calling global.Environment(). These images replace the ko:// tags in YAML files that are applied to the cluster with manifest.InstallYamlFS.

A go file local to the target YAML can have an install step function like:

//go:embed job.yaml
var jobTemplate embed.FS

func Install(message string) feature.StepFn {
	cfg := map[string]interface{}{
		"additional": "this",
		"customizations": message,
	}
	return func(ctx context.Context, t *testing.T) {
		if _, err := manifest.InstallYamlFS(ctx, jobTemplate, cfg); err != nil {
			t.Fatal(err)
		}
	}
}

Then given a YAML file:

apiVersion: batch/v1
kind: Job
metadata:
  name: echo
  namespace: { { .namespace } }
  labels:
    additional: { { .additional } }
spec:
  backoffLimit: 0
  parallelism: 1
  template:
    spec:
      restartPolicy: Never
      containers:
        - name: echo
          image: ko://knative.dev/reconciler-test/test/example/cmd/echo
          env:
            - name: ECHO
              value: "{{ .customizations }}"

Will be processed first as a go template, then applied the Environment using the dynamic client.

Communicating State

There are times when the test author would rather pass state from a Setup or Requirement of a feature without a complicated parameter passing or callbacks. An example of this would be generating names of resources. To Address this need, we added f.State.

If State is not set on the Feature then a new state.KVStore is assigned for the invocation of env.Test (or via env.TestSet).

State is stored into the context that is passed to each StepFn, implemented as a pointer to that feature instance's State object. Meaning, State is effectively global for the scope of the env.Test run.

Note: the default implementation in reconciler-test uses JSON marshaling to save and load values to/from the store. You may provide your own implementation by implementing the state.Store interface.

The recommended way to access state is to use the context accessors:

import knative.dev/reconciler-test/pkg/state

// Direct Store access:
store := state.FromContext(ctx) Store

store.Set(ctx, key, value)

store.Get(ctx, key, &value)

// Helpers to work with Store without needing fetch Store directly.

aString := state.GetStringOrFail(ctx, t, key)

state.GetOrFail(ctx, t, key, &value)

state.SetOrFail(ctx, t, key, value)

In use,

func FancyFeature(brokerName string) *feature.Feature {
	f := feature.NewFeatureNamed("MyNewFeature")

	f.Setup("Set Foo and Bar", func(ctx context.Context, t *testing.T) {
		state.SetOrFail(ctx, t, "foo", "baz-"+random)
        state.SetOrFail(ctx, t, "bar", CustomStruct{Exported:"values"})
	})

	f.Stable("An aspect of the feature").
		Should("make some assertion with foo", someAssertion).
		Must("another assertion with bar", anotherAssertion)

	return f
}

func someAssertion(ctx context.Context, t *testing.T) {
    foo := state.GetStringOrFail(ctx, t, "foo")
    // do something with the string `foo`.
}

func someAssertion(ctx context.Context, t *testing.T) {
    bar := CustomStruct{}
    state.GetOrFail(ctx, t, "bar", &bar)
    // do something with the struct `bar`.
}

This shows someAssertion can be written in a way that does not require it to have some complicated callback logic wrapping it but still get custom parameters that are dependent on the specific test run. State is useful for passing generated names of known keys between Setup and StepFns. It is intended to remove the need for oddly nested callbacks and globals. By default, State is scoped for the lifecycle of a Feature in the context of Test. Remember: when FancyFeature is called in the example above, its job is to compose a Feature for running later via env.Test or env.TestSet. With state, we are attempting to make it less difficult to communicate between Setup and Assert phases of testing.

Running Tests

Running tests is nothing more than using go test.

go test -v -count=1 -timeout=15m -tags=e2e ./test/...

And normal go test filters work on test entry point names:

go test -v -count=1 -tags=e2e ./test/... -run TestKoPublish

Filters

At the moment, all features and all requirements are defaulted on. These can be disabled using the following flags:

They can be used in combination, to run only Beta state features:

go test -v -count=1 -tags=e2e ./test/... --feature.any=false --feature.beta

Or, only alpha and beta state features for only Must and Must Not requirements:

go test -v -count=1 -tags=e2e ./test/... --feature.any=false --feature.beta --requirement.all=false --requirement.must --requirement.mustnot

And normal go filters work on the go test entry point names.

go test -v -count=1 -tags=e2e ./test/... --feature.any=false --feature.beta -run TestKoPublish

Run all instances of Noop feature, including instances in a Feature Set

go test -v -count=1 -tags=e2e ./test/... --feature=Noop