k3s/tests/TESTING.md

Testing Standards in K3s

Go testing in K3s comes in 3 forms: Unit, Integration, and End-to-End (E2E). This document will explain when each test should be written and how each test should be generated, formatted, and run.

Note: all shell commands given are relateive to the root k3s repo directory.

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Unit Tests

Unit tests should be written when a component or function of a package needs testing. Unit tests should be used for "white box" testing.

Framework

All unit tests in K3s follow a Table Driven Test style. Specifically, K3s unit tests are automatically generated using the gotests tool. This is built into the Go vscode extension, has documented integrations for other popular editors, or can be run via command line. Additionally, a set of custom templates are provided to extend the generated test's functionality. To use these templates, call:

gotests --template_dir=<PATH_TO_K3S>/contrib/gotests_templates

Or in vscode, edit the Go extension setting Go: Generate Tests Flags
and add --template_dir=<PATH_TO_K3S>/contrib/gotests_templates as an item.

To facilitate unit test creation, see tests/util/runtime.go helper functions.

Format

All unit tests should be placed within the package of the file they test.
All unit test files should be named: <FILE_UNDER_TEST>_test.go.
All unit test functions should be named: Test_Unit<FUNCTION_TO_TEST> or Test_Unit<RECEIVER>_<METHOD_TO_TEST>.
See the etcd unit test as an example.

Running

go test ./pkg/... -run Unit

Note: As unit tests call functions directly, they are the primary drivers of K3s's code coverage metric.

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Integration Tests

Integration tests should be used to test a specific functionality of k3s that exists across multiple Go packages, either via exported function calls, or more often, CLI comands. Integration tests should be used for "black box" testing.

Framework

All integration tests in K3s follow a Behavior Diven Development (BDD) style. Specifically, K3s uses Ginkgo and Gomega to drive the tests.
To generate an initial test, the command ginkgo bootstrap can be used.

To facilitate K3s CLI testing, see tests/util/cmd.go helper functions.

Format

Integration tests can be placed in two areas:

1. Next to the go package they intend to test.
2. In tests/integration/<TESTNAME> for package agnostic testing.

Package specific integration tests should use the <PACKAGE_UNDER_TEST>_test package.
Package agnostic integration tests should use the integration package.
All integration test files should be named: <TEST_NAME>_int_test.go
All integration test functions should be named: Test_Integration<Test_Name>.
See the etcd snapshot test as a package specific example.
See the local storage test as a package agnostic example.

Running

Integration tests can be run with no k3s cluster present, each test will spin up and kill the appropriate k3s server it needs.

go test ./pkg/... ./tests/integration/... -run Integration

Integration tests can be run on an existing single-node cluster via compile time flag, tests will skip if the server is not configured correctly.

go test -ldflags "-X 'github.com/rancher/k3s/tests/util.existingServer=True'" ./pkg/... ./tests/integration/... -run Integration

Integration tests can also be run via a Sonobuoy plugin on an existing single-node cluster.

./scripts/build-tests-sonobuoy
sudo KUBECONFIG=/etc/rancher/k3s/k3s.yaml sonobuoy run --plugin ./dist/artifacts/k3s-int-tests.yaml

Check the sonobuoy status and retrieve results

sudo KUBECONFIG=/etc/rancher/k3s/k3s.yaml sonobuoy status
sudo KUBECONFIG=/etc/rancher/k3s/k3s.yaml sonobuoy retrieve
sudo KUBECONFIG=/etc/rancher/k3s/k3s.yaml sonobuoy results <TAR_FILE_FROM_RETRIEVE>

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End-to-End (E2E) Tests

End-to-end tests utilize Ginkgo and Gomega like the integration tests, but rely on separate testing utilities and are self-contained within the test/e2e directory. E2E tests cover complete K3s single and multi-cluster configuration and administration: bringup, update, teardown etc.
E2E tests are run nightly as part of K3s quality assurance (QA).

Format

All E2E tests should be placed under the e2e package.
All E2E test functions should be named: Test_E2E<TEST_NAME>.
See the upgrade cluster test as an example.

Running

Generally, E2E tests are run as a nightly Jenkins job for QA. They can still be run locally but additional setup may be required.

go test ./tests/e2e... -run E2E

Contributing New Or Updated Tests

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We gladly accept new and updated tests of all types. If you wish to create a new test or update an existing test, please submit a PR with a title that includes the words <NAME_OF_TEST> (Created/Updated).