function runMochaJSONAsync(fixturePath, args = [], opts = {}) {
  return new Promise((resolve, reject) => {
    runMochaJSON(
      fixturePath,
      args,
      (err, result) => {
        if (err) {
          return reject(err);
        }
        resolve(result);
      },
      opts
    );
  });
}
Like {@link runMochaJSON}, but returns a `Promise`.
@param {string} fixturePath - Path to (or name of, or basename of) fixture file
@param {Options} [args] - Command-line args
@param {Object} [opts] - Options for `child_process.spawn`
@returns {Promise<JSONResult>}