Run Prow integration tests

Run all integration tests

./prow/test/integration/integration-test.sh

Run a specific integration test

./prow/test/integration/integration-test.sh -run=TestIWantToRun

Cleanup

./prow/test/integration/teardown.sh -all

Adding new integration tests

New component

Assume we want to add most-awesome-component (source code in prow/cmd/most-awesome-component).

  1. Add most-awesome-component to the PROW_COMPONENTS, PROW_IMAGES, and PROW_IMAGES_TO_COMPONENTS variables in lib.sh.

    • Add the line most-awesome-component to PROW_COMPONENTS.
    • Add the line [most-awesome-component]=prow/cmd/most-awesome-component to PROW_IMAGES.
    • Add the line [most-awesome-component]=most-awesome-component to PROW_IMAGES_TO_COMPONENTS.
    • Explanation: PROW_COMPONENTS lists which components are deployed into the cluster, PROW_IMAGES describes where the source code is located for each component (in order to build them), and finally PROW_IMAGES_TO_COMPONENTS defines the relationship between the first two variables (so that the test framework knows what to redeploy depending on what image has changed). As an example, the deck and deck-tenanted components (in PROW_COMPONENTS) both use the deck image (defined in PROW_IMAGES_TO_COMPONENTS), so they are both redeployed every time you change something in prow/cmd/deck (defined in PROW_IMAGES).
  2. Set up Kubernetes Deployment and Service configurations inside the [configuration folder][config/prow/cluster] for your new component. This way the test cluster will pick it up when it deploys Prow components.

    • If you want to deploy an existing Prow component used in production (i.e., https://prow.k8s.io), you can reuse (symlink) the configurations used in production. See the examples in [configuration folder][config/prow/cluster].

    • Remember to use localhost:5001/most-awesome-component for the image: ... field in the Kubernetes configurations to make the test cluster use the freshly-built image.

New tests

Tests are written under the test directory. They are named with the pattern <COMPONENT>_test.go*. Continuing the example above, you would add new tests in most-awesome-component_test.go

Check that your new test is working

  1. Add or edit new tests (e.g., func TestMostAwesomeComponent(t *testing.T) {...}) in most-awesome-component_test.go.
  2. Run ./prow/test/integration/integration-test.sh -run=TestMostAwesomeComponent to bring up the test cluster and to only test your new test named TestMostAwesomeComponent.
  3. If you need to make changes to most-awesome-component_test.go (and not the component itself), run ./prow/test/integration/integration-test.sh -run=TestMostAwesomeComponent -no-setup. The -no-setup will ensure that the test framework avoid redeploying the test cluster.
    • If you do need to make changes to the Prow component, run ./prow/test/integration/integration-test.sh -run=TestMostAwesomeComponent -build=most-awesome-component so that prow/cmd/most-awesome-component is recompiled and redeployed into the cluster before running TestMostAwesomeComponent.

If Step 2 succeeds and there is nothing more to do, you’re done! If not (and your tests still need some tweaking), repeat steps 1 and 3 as needed.

How it works

In short, the integration-test.sh script creates a KIND Kubernetes cluster, runs all available integration tests, and finally deletes the cluster.

Recall that Prow is a collection of services (Prow components) that can be deployed into a Kubernetes cluster. KIND provides an environment where we can deploy certain Prow components, and then from the integration tests we can create a Kubernetes Client to talk to this deployment of Prow.

Note that the integration tests do not test all components (we need to fix this). The PROW_COMPONENTS variable is a list of components currently tested. These components are compiled and deployed into the test cluster on every invocation of integration-test.sh.

Each tested component needs a Kubernetes configuration so that KIND understands how to deploy it into the cluster, but that’s about it (more on this below). The main thing to keep in mind is that the integration tests must be hermetic and reproducible. For this reason, all components that are tested must be configured so that they do not attempt to reach endpoints that are outside of the cluster. For example, this is why some Prow components have a -github-endpoint=... flag that you can use — this way these components can be instructed to talk to the fakeghserver deployed inside the cluster instead of trying to talk to GitHub.

Code layout

.
├── cmd # Binaries for fake services deployed into the test cluster along with actual Prow components.
│   ├── fakegerritserver # Fake Gerrit.
│   ├── fakeghserver # Fake GitHub.
│   └── fakegitserver # Fake low-level Git server. Can theoretically act as the backend for fakeghserver or fakegerritserver.
├── config # Kubernetes configuration files.
│   └── prow # Prow configuration for the test cluster.
│       ├── cluster # KIND test cluster configurations.
│       └── jobs # Static Prow jobs. Some tests use these definitions to run Prow jobs inside the test cluster.
├── internal
│   └── fakegitserver
└── test # The actual integration tests to run.
    └── testdata # Test data.

Last modified December 1, 2022: Organize Legacy Snapshot docs (#26) (9ce71a0a9)