Creating request stub with sinon in mocha

Question

I'm using mocha to test some classes and I need to create a stub of request library.

I'm using sinon, and I'm able to create a stub of the request.get method but I'm not able to create a stub of the request method (the http calls try to connect to a server). As I have read, request.get is an alias for request but when I stub request.get it has no effect over request calls.

This code works (using request.get):

In tests:

request = require 'request'

describe "User test", ->
  user = {}
  before (done) ->
    user = new test.user('Ander', 18)    
    sinon.stub(request, 'get').yields(null, {statusCode: 200}, 'foo')        
    done()
  after (done) ->
    request.get.restore()
    done()
  it "testing server response", ->
    user.getData().should.equal 'ander'

In source:

request = require 'request'

class User
  contructor(@name, @age): ->
  getData: ->
    mydata = ''
    request.get 'http://127.0.0.1:8080/', (err, response, body) ->        
      if not err and response.statusCode == 200
        mydata = body
      else
        err = throw new Error "Errorea"
    mydata

But this doesn't work (tries to connect to the supplied url):

In tests:

request = require 'request'

describe "User test", ->
  user = {}
  before (done) ->
    user = new test.user('Ander', 18)    
    sinon.stub(request, 'Request').yields(null, {statusCode: 200}, 'foo')
    #Creating the stub this way, doesn't work neither
    #sinon.stub(request, 'get').yields(null, {statusCode: 200}, 'foo')
    done()
  after (done) ->
    request.Request.restore()
    done()
  it "testing server response", ->
    user.getData().should.equal 'ander'

In source:

request = require 'request'

class User
  contructor(@name, @age): ->
  getData: ->
    mydata = ''
    request 'http://127.0.0.1:8080/', (err, response, body) ->        
      if not err and response.statusCode == 200
        mydata = body
      else
        err = throw new Error "Errorea"
    mydata

Which is the right way to create a stub for request call? Which is the method to be stubed?

Answer 1

Although request is a great library, it is not a good example of well structured API. And because module request is defined as a function with additional methods (similarly like express), as what I know you can't create stub for function request with sinon.

The best thing you can do is to avoid to use request function in your code and use only request.get, request.post, etc., which you can easily stub.

Creating stub for Request in your second example doesn't help because Request is not a method, see source code.

Answer 2

If anyone is still looking for an answer for this, it looks like you can create a stub for request using sinon:

before(function(done){
  sinon
    .stub(request, 'get')
    .yields(null, null, JSON.stringify({login: "bulkan"}));
  done();
});

more details can be found here

Answer 3

Another workaround would be generating a stub using sinon module and the request dependency in the corresponding module can be overridden using proxyquire.

var sinon = require('sinon');
var proxyquire = require('proxyquire');

describe('something', function(){
  var request;
  var overriddenModule;
  before(function(){
    request = sinon.stub();
    // overriding the 'request' dependency with the stub
    overriddenModule = proxyquire('path_to_module_using_request', {'request': request});     
  });
  it("should do something",function(done){
    // stubbing the request(options,callback) method
    request.withArgs(sinon.match.any,sinon.match.any).yields(null,null,responseBody);
    overriddenModule.method_which_is_doing_request;
    // our logic and assertions before calling done()
  });  
});

For more info, check this article on Unit Testing with Mocks in Node

Answer 4

As mentioned in one of the answers to the question How to mock request and response in nodejs to test middleware/controllers?, the node-mocks-http package provides a way to build request and response mocks.