Test a snap in CI

Building a snap in CI is only half the story: before it reaches the Snap Store, you want to verify that the built snap actually installs and runs. The test reusable workflow does exactly that: it installs the snap(s) built during the run and optionally executes a custom test script.

Prerequisites

• A GitHub repository containing a snap project.

• A workflow that builds your snap, for example the one from the snap CI tutorial. The test workflow expects the snap artifacts produced by the build workflow to be present in the same run.

Test with the snap workflow

The snap workflow already runs the test workflow between the build and the publish steps. By default, it only verifies that the snap installs and calls snap info on it.

Add a custom test script with the snap-test-script input. The script runs with bash -euxo pipefail, so any failing command fails the pipeline:

jobs:
  snap:
    permissions:
      contents: read
    uses: canonical/robotics-actions-workflows/.github/workflows/snap.yaml@main
    with:
      snap-test-script: |
        #!/bin/sh
        set -euxo pipefail
        hello-snap | grep "Hello World"
    secrets:
      snapstore-login: ${{ secrets.SNAPSTORE_LOGIN }}

Adapt the script to exercise the actual commands your snap ships.

Note

The test workflow installs every *.snap file it finds in the run artifacts that matches the architecture of the runner. When your repository builds several snaps, for example with a list in snapcraft-source-subdir, the same test job installs them all and runs the test script against the whole deployment. This is convenient for intricate multi-snap setups.

Test inside an LXD container

GitHub-hosted runners only offer a limited set of operating systems. To test your snap on an image that is not available as a runner, for example Ubuntu 20.04 LTS, set the lxd-image input. The workflow then launches an LXD container, installs snapd and your snap inside it, and executes the test script inside the container:

jobs:
  snap:
    permissions:
      contents: read
    uses: canonical/robotics-actions-workflows/.github/workflows/snap.yaml@main
    with:
      lxd-image: "ubuntu:20.04"
      snap-test-script: |
        #!/bin/sh
        set -euxo pipefail
        hello-snap | grep "Hello World"
    secrets:
      snapstore-login: ${{ secrets.SNAPSTORE_LOGIN }}

The value must be an image alias from an LXD remote, For example one listed by lxc image list ubuntu:.

Tune the installation

Use snap-install-args to control how the snap is installed. The default is --dangerous, which allows installing the unsigned, locally built snap. Add further flags when needed, for example:

    with:
      snap-install-args: "--dangerous --jailmode"

See the test workflow reference for the full list of inputs.