A ruby script we use to test our Rego policies. They need to be in the policies/ folder. Each line that is not exercised by tests will make it fail.

desc "Test policies"
task test: ["update:opa"] do
  output = `opa test --coverage --verbose policies/* 2>&1`
  abort output unless $?.success?

  coverage = JSON.parse(output).fetch("files")
  errors = policy_files.flat_map do |policy|
    return [policy] unless result = coverage[policy] # untested

    (result["not_covered"] || []).map do |line|
      start = line.dig("start", "row")
      finish = line.dig("end", "row")
      "#{policy}:#{start}#{"-#{finish}" if start != finish}"
    end
  end
  abort "Missing coverage:\n#{errors.join("\n")}" if errors.any?
end