expect/lib/SpyUtils.js

Write better assertions

'use strict';

exports.__esModule = true;
exports.createSpy = createSpy;
exports.spyOn = spyOn;
exports.isSpy = isSpy;

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }

var _invariant = require('./invariant');

var _invariant2 = _interopRequireDefault(_invariant);

var _isFunction = require('./isFunction');

var _isFunction2 = _interopRequireDefault(_isFunction);

function noop() {}

function createSpy(fn) {
  if (fn == null) fn = noop;

  _invariant2['default'](_isFunction2['default'](fn), 'createSpy needs a function');

  var targetFn = undefined,
      thrownValue = undefined,
      returnValue = undefined;

  var spy = function spy() {
    spy.calls.push({
      context: this,
      arguments: Array.prototype.slice.call(arguments, 0)
    });

    if (targetFn) return targetFn.apply(this, arguments);

    if (thrownValue) throw thrownValue;

    return returnValue;
  };

  spy.calls = [];

  spy.andCall = function (fn) {
    targetFn = fn;
    return spy;
  };

  spy.andCallThrough = function () {
    return spy.andCall(fn);
  };

  spy.andThrow = function (object) {
    thrownValue = object;
    return spy;
  };

  spy.andReturn = function (value) {
    returnValue = value;
    return spy;
  };

  spy.getLastCall = function () {
    return spy.calls[spy.calls.length - 1];
  };

  spy.__isSpy = true;

  return spy;
}

function spyOn(object, methodName) {
  var original = object[methodName];

  if (original == null || !original.__isSpy) {
    var spy = createSpy(original);

    spy.restore = spy.destroy = function () {
      object[methodName] = original;
    };

    object[methodName] = spy;
  }

  return object[methodName];
}

function isSpy(object) {
  return object && object.__isSpy === true;
}