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Version: 1.7

Testing for policy authors

Kubewarden policies are regular programs compiled as WebAssembly (Wasm). As with any kind of program, good test coverage is important.

Policy authors can use their favorite development environments. You can use familiar tools, and testing frameworks to verify development.

These two Kubewarden policies provide an example written in Rust and Go:

They both have test suites using standard testing for their development environments.

The policies use GitHub Actions for their CI pipelines.

End-to-end tests

You can also write tests that execute against the Wasm binary containing your policy. This can be done without having to deploy a Kubernetes cluster by using these tools:

  • bats: is used to write tests and automate their execution.
  • kwctl: Kubewarden's default CLI tool that helps you with policy-related operations; pull, inspect, annotate, push, and run.

To use kwctl run the following input is needed:

  1. Wasm binary file reference of the policy to be run. The Kubewarden policy can be loaded from the local filesystem (file://), an HTTP(s) server (https://), or an OCI registry (registry://).
  2. The admission request object to be tested. You provide it via the --request-path argument. Or you can provide it on stdin by setting --request-path to -.
  3. Provide policy settings for run time as an inline JSON via --settings-json flag. Or a JSON, or a YAML file loaded from the filesystem via --settings-path.

After the test kwctl prints the ValidationResponse object to standard output.

This is how you use kwctl to test the Wasm binary of ingress-policy linked to above:

$ curl https://raw.githubusercontent.com/kubewarden/ingress-policy/v0.1.8/test_data/ingress-wildcard.json 2> /dev/null | \
kwctl run \
--settings-json '{"allowPorts": [80], "denyPorts": [3000]}' \
--request-path - \
registry://ghcr.io/kubewarden/policies/ingress:v0.1.8 | jq

Using bats you can write a test that runs this command and looks for the expected outputs:

A bats test
@test "all is good" {
run kwctl run \
--request-path test_data/ingress-wildcard.json \
--settings-json '{"allowPorts": [80], "denyPorts": [3000]}' \
ingress-policy.wasm

# this prints the output when one the checks below fails
echo "output = ${output}"

# settings validation passed
[[ "$output" == *"valid: true"* ]]

# request accepted
[[ "$output" == *"allowed: true"* ]]
}

You can put the code in a file, e2e.bats, for example, and then invoke bats by:

$ bats e2e.bats
✓ all is good

1 tests, 0 failures

This section of the documentation has more about writing end-to-end tests of your policies.