Mocking / Stubbing tns-core-modules for NativeScript testing on your host device

test.js

var assert = require('assert');
var proxyquire = require('proxyquire');
var fetchStub = require('node-fetch'); // the npm package not the tns-core-module (npm install --save-dev node-fetch)
var obsArray = Array;


var YourViewModel = proxyquire('../app/view-models/your-view-model',
    {
      fetch: fetchStub,
      "data/observable-array": {
        ObservableArray: Array,
        '@noCallThru': true
      }
    });

describe('YourViewModel', function () {
  describe('load', function () {
    it('should load the shit', function () {
      var yvm = YourViewModel();
      yvm.push({title: 'this item'})
      assert(yvm.length, 1);
    });
  });
});