How to unit test angularjs form?

Question

I have been learning AngularJS and things have been going pretty smoothly regarding unit testing, but I've reached a bit of a tricky spot.

Suppose I have a simple form, for example:

<form name="form">
    <input type="text" name="number" ng-pattern="/^d+$/">
</form>

If I was testing something like a controller, I know that I would write it something like this (using Jasmine + Karma):

beforeEach(module('some.module'));

beforeEach(inject(/* services */) {
    /* inject necessary services */
});

it('should be invalid when given bad input', function () {
    form.number = 'Not a number';
    expect(form.number.$valid).toBeFalsy();
    expect(form.$valid).toBeFalsy();
});

But I don't know which services I need to inject, and I haven't had any luck finding documentation on unit testing in either the forms guide or the ng-form documentation.

How does one unit test a form in Angular?

Answer 1

I'm not convinced this is the best way to unit test something like this but with some help from this answer on testing custom angular directives and some experimentation, I figured out a way to unit test the form.

After installing karma-ng-html2js-preprocessor and configuring it, I managed to get a working unit test like this:

var scope, form;

beforeEach(function() {
  module('my-module');
  module('templates');
});

beforeEach(inject($rootScope, $controller, $templateCache, $compile) {
    scope = $rootScope.$new()

    ctrl = $controller('MyController'), {
        "$scope": scope
    }

    templateHtml = $templateCache.get('path/to/my/template.html')
    formElem = angular.element("<div>" + templateHtml + "</div>")
    $compile(formElem)(scope)
    form = scope.form

    scope.$apply()
}

it('should not allow an invalid `width`', function() {
  expect(form.$valid).toBeTruthy();
  form.number.$setViewValue('BANANA');
  expect(form.number.$valid).toBeFalsy()
});

Answer 2

I guess i can add some details to the accepted answer: karma-ng-html2js-preprocessor should be configured in the karma.conf.js file in a similar way:

//karma.conf.js
ngHtml2JsPreprocessor: { 
    moduleName: 'templates'
},
files: [
    //... other files
    //my templates 
    'app/**/*.html'
],
preprocessors: {
    'app/**/*.html': ['ng-html2js']
}, 
plugins: [
    //... other plugins
    "karma-ng-html2js-preprocessor"
]

Answer 3

Here's a way to unit test with an angular form without having to compile a controller's template. Works well for me in my limited usage.

describe('Test', function() {

  var $scope, fooController;

  beforeEach(function($rootScope, $controller, formDirective) {

    $scope = $rootScope.$new();
    fooController = $controller('fooController', {$scope: $scope});

    // we manually create the form controller
    fooController.form = $controller(formDirective[0].controller, {
      $scope: $scope,
      $element: angular.element("<form></form>"),
      $attrs: {}
    });

  });

  it('should test something', function() {
    expect(fooController.form.$valid).toBeFalsy();
  });

});

Answer 4

Alternatively, if you are using WebPack with karma-webpack - you can include the template with require, without the need of karma-ng-html2js-preprocessor package:

describe("MyCtrl's form", function () {
    var $scope,
        MyCtrl;

    beforeEach(angular.mock.module("my.module"));

    beforeEach(inject(function (_$rootScope_, _$controller_, _$compile_) {
        $scope = _$rootScope_.$new();

        // Execute the controller's logic
        // Omit the ' as vm' suffix if you are not using controllerAs
        MyCtrl = _$controller_("MyCtrl as vm", { $scope: $scope });

        // Compile the template against our scope to populate form variables
        var html = require("./my.template.html"),
            template = angular.element(html);

        _$compile_(template)($scope);
    }));

    it('should be invalid when given bad input', function () {
        MyCtrl.form.number.$setViewValue('Not a number');
        expect(MyCtrl.form.number.$valid).toBeFalsy();
        expect(MyCtrl.form.$valid).toBeFalsy();
    });
});

HTML:

<form name="vm.form">
    <input type="text" name="number" ng-pattern="/^d+$/">
</form>