uppy/packages/@uppy/companion/test/__mocks__/purest.js

const fs = require('fs')
const qs = require('querystring')
const fixtures = require('../fixtures').providers

class MockPurest {
  constructor (opts) {
    const methodsToMock = ['query', 'select', 'where', 'auth', 'json', 'options']
    const httpMethodsToMock = ['get', 'put', 'post', 'head', 'delete']
    methodsToMock.forEach((item) => {
      this[item] = () => this
    })
    httpMethodsToMock.forEach((item) => {
      this[item] = (url) => {
        this._requestUrl = url
        this._method = item
        return this
      }
    })
    this.opts = opts
  }

  qs (data) {
    this._query = qs.stringify(data)
    return this
  }

  request (done) {
    if (typeof done === 'function') {
      const responses = fixtures[this.opts.providerName].responses
      const url = this._query ? `${this._requestUrl}?${this._query}` : this._requestUrl
      const endpointResponses = responses[url] || responses[this._requestUrl]
      const body = endpointResponses[this._method]
      done(null, { body, statusCode: 200 }, body)
    }

    return this
  }

  on (evt, cb) {
    if (evt === 'response') {
      cb(fs.createReadStream('./README.md'))
    }
    return this
  }
}

module.exports = () => {
  return (options) => new MockPurest(options)
}