How integration tests work

Cortex integration tests are written in Go and based on a custom framework running Cortex and its dependencies in Docker containers and using the Go testing package for assertions. Integration tests run in CI for every PR, and can be easily executed locally during development (it just requires Docker).

How to run integration tests

When integration tests run in CI, we build the Cortex docker image based on the PR code and then run the integration tests against it. When running tests locally you should build the Cortex Docker image first:

make ./cmd/cortex/.uptodate

This will locally build the quay.io/cortexproject/cortex:latest image used by integration tests. Whenever the Cortex code changes (cmd/, pkg/ or vendors) you should rebuild the Cortex image, while it’s not necessary to rebuild it while developing integration tests.

Once the Docker image is built, you can run integration tests:

go test -v -tags=requires_docker ./integration/...

If you want to run a single test you can use a filter. For example, to only run TestChunksStorageAllIndexBackends:

go test -v -tags=requires_docker ./integration -run "^TestChunksStorageAllIndexBackends$"

Supported environment variables

  • CORTEX_IMAGE
    Docker image used to run Cortex in integration tests (defaults to quay.io/cortexproject/cortex:latest)
  • CORTEX_CHECKOUT_DIR
    The absolute path of the Cortex repository local checkout (defaults to $GOPATH/src/github.com/cortexproject/cortex) – E2E_TEMP_DIR
    The absolute path to a directory where the integration test will create an additional temporary directory to store files generated during the test. – E2E_NETWORK_NAME
    Name of the docker network to create and use for integration tests. If no variable is set, defaults to e2e-cortex-test.

The requires_docker tag

Integration tests have requires_docker tag (// +build requires_docker line followed by empty line on top of Go files), to avoid running them unintentionally as they require Docker, e.g. by running go test ./... in main Cortex package.

Isolation

Each integration test runs in isolation. For each integration test, we do create a Docker network, start Cortex and its dependencies containers, push/query series to/from Cortex and run assertions on it. Once the test has done, both the Docker network and containers are terminated and deleted.