local output_file_missing=0
  local output_file
  for output_file in \
    "${AGGREGATOR_CERT_DIR}/pki/private/ca.key" \
    "${AGGREGATOR_CERT_DIR}/pki/ca.crt" \
    "${AGGREGATOR_CERT_DIR}/pki/issued/proxy-client.crt" \
    "${AGGREGATOR_CERT_DIR}/pki/private/proxy-client.key"
  do
    if [[ ! -s "${output_file}" ]]; then
      echo "Expected file ${output_file} not created" >&2
      output_file_missing=1

                void transform(TransformOutputs outputs) {
                    def outputFile = outputs.file("some/dir/output.txt")
                    assert outputFile.parentFile.directory
                    outputFile.text = "output"
                    def outputDir = outputs.dir("another/output/dir")
                    assert outputDir.directory