strapi/test/helpers/waitRestart.js

const request = require('request-promise-native');

module.exports = function(initTime = 200) {
  const ping = async () => {
    return new Promise((resolve, reject) => {
      // ping _health
      request({
        url: 'http://localhost:1337/_health',
        method: 'HEAD',
        mode: 'no-cors',
        json: true,
        headers: {
          'Content-Type': 'application/json',
          'Keep-Alive': false,
        },
      }).then(resolve, reject);
    }).catch(() => {
      return new Promise(resolve => setTimeout(resolve, 200)).then(ping);
    });
  };

  return new Promise(resolve => setTimeout(resolve, initTime)).then(ping);
};