如何在Jasmine / Angularjs中对下拉列表进行单元测试

Question

I am trying to unit test a directive that makes a dropdown list using some JSON to specify the details of the list. The directive works fine, but I'm having issues while trying to unit test it.

Here's the test:

/* global inject, expect, angular */

define(function(require){
  'use strict';
  require('angular');
  require('angularMock');
  require('reporting/js/directives/app.directives');
  require('reporting/js/directives/drop.down.field.directive');

  describe("drop down field", function() {
    // debugger;
    var directive, scope;
    beforeEach(module('app.directives'));
    beforeEach(inject(function($compile, $rootScope) {
      scope = $rootScope;

      scope.dropDownResponses = {};
      scope.dropDownField = {
        "name": "Test Drop Down",
        "type": "dropdown",
        "hidden": "false",
        "defaultValue": "None",
        "values": [
          {
            "key": "1",
            "value": "FL",
            "select": "true"
          },
          {
            "key": "2",
            "value": "GA",
            "select": "false"
          },
          {
            "key": "3",
            "value": "TX",
            "select": "false"
          }
        ],
        "validation": null
      };
      directive = angular.element('<div drop-down-field="dropDownField" drop-down-responses="dropDownResponses"></div>');
      $compile(directive)(scope);
      scope.$digest();
    }));
    it("should build three dropdown choices", function() {
      expect(directive.find('option').length).toBe(4);
    });
    it('should have one dropdown', function() {
      expect(directive.find("select").length).toBe(1);
    });
    it('should update the model when a new choice is selected', function() {
      angular.element(directive.find("select")[0]).val('1');
      angular.element(directive.find("select")[0]).change();
      expect(scope.dropDownResponses[scope.dropDownField.name]).toBe("1");
    });
  });
});

Here's the directive:

define(function(require) {
  'use strict';

  var module = require('reporting/js/directives/app.directives');
  var template = require('text!reporting/templates/drop.down.field.tpl');

  module.directive('dropDownField', function () {
    return {
      restrict: 'A',
      replace: true,
      template:template,
      scope: {
        dropDownField : "=",
        dropDownResponses : "="
      }
    };
  });

  return module;
});

Here's the markup:

<div>
  {{dropDownField.name}}
  <select ng-model="dropDownResponses[dropDownField.name]" ng-options="value.key as value.value for value in dropDownField.values"></select>
</div>

The last it block is what is of concern here. When I fire the change event, the value on the model always winds up being one more that expected. For instance, the value stored in scope.dropDownResponses in this case winds up being 2.

Any ideas?

Answer 1

Its coming up to this questions first birthday and I found it intriguing as to why the test is not passing.

I have come to the conclusion that the premise of the test is wrong as the test

expect(scope.dropDownResponses[scope.dropDownField.name]).toBe("1");

should be

expect(scope.dropDownResponses[scope.dropDownField.name]).toBe("2");

The reason for this is that the the value stored in scope.dropDownResponses is in fact 2 as the questioner found.

When you are selecting by val('1') you are selecting the second option in the select element

<select ng-model="dropDownResponses[dropDownField.name]" ng-options="value.key as value.value for value in dropDownField.values" class="ng-valid ng-dirty">
  <option value="0" selected="selected">FL</option>
  <option value="1">GA</option>
  <option value="2">TX</option>
</select>

which reflects the second item in the array in the spec

{
  "key": "2",
  "value": "GA",
  "select": "false"
},

You can see this in action in this jsfiddle where the console.log output

it('should update the model when a new choice is selected', function() {
  console.log(angular.element(directive.find("select")));
  console.log('selected before = ' + angular.element(directive.find("select option:selected")).text());
  angular.element(directive.find("select")[0]).val(1);
  console.log('selected after = ' + angular.element(directive.find("select option:selected")).text());
  angular.element(directive.find("select")[0]).change();
  console.log('selected Text value = ' + angular.element(directive.find("select option:selected")).text());
  expect(scope.dropDownResponses[scope.dropDownField.name]).toBe("2");
  console.log(scope.dropDownResponses[scope.dropDownField.name]);
  //console.log('selectedIndex=' + angular.element(directive.find("select")).selectIndex());
  console.log(angular.element(directive.find("select"))[0]);
});

is

selected before = 
(index):98 selected after = GA
(index):100 selected Text value = GA
(index):102 2