Unit test request-promise, promise() is not a function

Question

I am trying to unit test this function with sinon/mocha which uses request-promise. I attach the .promise() to allow access to all the Bluebird promise methods.

According to the request-promise readme:

rp(...).promise() or e.g. rp.head(...).promise() which returns the underlying promise so you can access the full Bluebird API

myModule.js var requestPromise = require('request-promise');

function requestWrapper(opts) {
   // Adds .promise() to allow access to Bluebird methods
   return requestPromise(opts).promise();
}

module.exports = requestWrapper;

Unit test

var Promise = require('bluebird');
var requestPromise = sinon.stub().returns(Promise.resolve());
var rewire = require('rewire');
var myModule = rewire('./myModule');

myModule.__set__({
  requestPromise: requestPromise
});

describe('myModule', function() {
  var testPromise;

  it('should...', function() {
      testPromise = myModule.requestWrapper({ method: 'GET', url: 'http://someurl.com' })
  });
});

Error

I'm getting the following error: TypeError: requestPromise(...).promise is not a function.

score 1 · Answer 1 · answered Nov 17 '17 at 03:01

You're mocking is wrong (but close).

request-promise is a function that returns an object that has a function promise that returns the underlying promise.

What you've done with your stub & rewire is set request-promise to be a function that returns a promise.

A possible fix:

var requestPromise = sinon.stub().returns({ promise: () => Promise.resolve() });

Unit test request-promise, promise() is not a function

1 Answers1