message: chore: ensure build dir
diff: @@ -5,6 +5,7 @@ main().catch(swallow)
  // set-up local testing env
  async function main() {
  + fs.ensureDir(path.join(__dirname, '../build'))
  const depsPath = path.join(__dirname, '../deps')
  const destPath = path.join(__dirname, '../node_modules')
  if (await isDirectory(depsPath)) {
  