angular-docs-cn/packages/upgrade/static/test/integration/downgrade_component_spec.ts

/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

import {ChangeDetectionStrategy, Compiler, Component, Directive, ElementRef, EventEmitter, Injector, Input, NgModule, NgModuleRef, OnChanges, OnDestroy, Output, SimpleChanges, destroyPlatform} from '@angular/core';
import {async, fakeAsync, tick} from '@angular/core/testing';
import {BrowserModule} from '@angular/platform-browser';
import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';
import {UpgradeComponent, UpgradeModule, downgradeComponent} from '@angular/upgrade/static';
import * as angular from '../../../src/common/src/angular1';

import {html, multiTrim, withEachNg1Version} from '../../../src/common/test/helpers/common_test_helpers';
import {$apply, bootstrap} from './static_test_helpers';

withEachNg1Version(() => {
  describe('downgrade ng2 component', () => {

    beforeEach(() => destroyPlatform());
    afterEach(() => destroyPlatform());

    it('should bind properties, events', async(() => {
         const ng1Module = angular.module_('ng1', []).run(($rootScope: angular.IScope) => {
           $rootScope['name'] = 'world';
           $rootScope['dataA'] = 'A';
           $rootScope['dataB'] = 'B';
           $rootScope['modelA'] = 'initModelA';
           $rootScope['modelB'] = 'initModelB';
           $rootScope['eventA'] = '?';
           $rootScope['eventB'] = '?';
         });

         @Component({
           selector: 'ng2',
           inputs: ['literal', 'interpolate', 'oneWayA', 'oneWayB', 'twoWayA', 'twoWayB'],
           outputs: [
             'eventA', 'eventB', 'twoWayAEmitter: twoWayAChange', 'twoWayBEmitter: twoWayBChange'
           ],
           template: 'ignore: {{ignore}}; ' +
               'literal: {{literal}}; interpolate: {{interpolate}}; ' +
               'oneWayA: {{oneWayA}}; oneWayB: {{oneWayB}}; ' +
               'twoWayA: {{twoWayA}}; twoWayB: {{twoWayB}}; ({{ngOnChangesCount}})'
         })
         class Ng2Component implements OnChanges {
           ngOnChangesCount = 0;
           ignore = '-';
           literal = '?';
           interpolate = '?';
           oneWayA = '?';
           oneWayB = '?';
           twoWayA = '?';
           twoWayB = '?';
           eventA = new EventEmitter();
           eventB = new EventEmitter();
           twoWayAEmitter = new EventEmitter();
           twoWayBEmitter = new EventEmitter();

           ngOnChanges(changes: SimpleChanges) {
             const assert = (prop: string, value: any) => {
               const propVal = (this as any)[prop];
               if (propVal != value) {
                 throw new Error(`Expected: '${prop}' to be '${value}' but was '${propVal}'`);
               }
             };

             const assertChange = (prop: string, value: any) => {
               assert(prop, value);
               if (!changes[prop]) {
                 throw new Error(`Changes record for '${prop}' not found.`);
               }
               const actualValue = changes[prop].currentValue;
               if (actualValue != value) {
                 throw new Error(
                     `Expected changes record for'${prop}' to be '${value}' but was '${actualValue}'`);
               }
             };

             switch (this.ngOnChangesCount++) {
               case 0:
                 assert('ignore', '-');
                 assertChange('literal', 'Text');
                 assertChange('interpolate', 'Hello world');
                 assertChange('oneWayA', 'A');
                 assertChange('oneWayB', 'B');
                 assertChange('twoWayA', 'initModelA');
                 assertChange('twoWayB', 'initModelB');

                 this.twoWayAEmitter.emit('newA');
                 this.twoWayBEmitter.emit('newB');
                 this.eventA.emit('aFired');
                 this.eventB.emit('bFired');
                 break;
               case 1:
                 assertChange('twoWayA', 'newA');
                 assertChange('twoWayB', 'newB');
                 break;
               case 2:
                 assertChange('interpolate', 'Hello everyone');
                 break;
               default:
                 throw new Error('Called too many times! ' + JSON.stringify(changes));
             }
           }
         }

         ng1Module.directive('ng2', downgradeComponent({
                               component: Ng2Component,
                             }));

         @NgModule({
           declarations: [Ng2Component],
           entryComponents: [Ng2Component],
           imports: [BrowserModule, UpgradeModule]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const element = html(`
           <div>
             <ng2 literal="Text" interpolate="Hello {{name}}"
                 bind-one-way-a="dataA" [one-way-b]="dataB"
                 bindon-two-way-a="modelA" [(two-way-b)]="modelB"
                 on-event-a='eventA=$event' (event-b)="eventB=$event"></ng2>
             | modelA: {{modelA}}; modelB: {{modelB}}; eventA: {{eventA}}; eventB: {{eventB}};
           </div>`);

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then((upgrade) => {
           expect(multiTrim(document.body.textContent))
               .toEqual(
                   'ignore: -; ' +
                   'literal: Text; interpolate: Hello world; ' +
                   'oneWayA: A; oneWayB: B; twoWayA: newA; twoWayB: newB; (2) | ' +
                   'modelA: newA; modelB: newB; eventA: aFired; eventB: bFired;');

           $apply(upgrade, 'name = "everyone"');
           expect(multiTrim(document.body.textContent))
               .toEqual(
                   'ignore: -; ' +
                   'literal: Text; interpolate: Hello everyone; ' +
                   'oneWayA: A; oneWayB: B; twoWayA: newA; twoWayB: newB; (3) | ' +
                   'modelA: newA; modelB: newB; eventA: aFired; eventB: bFired;');
         });
       }));

    it('should bind properties to onpush components', async(() => {
         const ng1Module = angular.module_('ng1', []).run(
             ($rootScope: angular.IScope) => { $rootScope['dataB'] = 'B'; });

         @Component({
           selector: 'ng2',
           inputs: ['oneWayB'],
           template: 'oneWayB: {{oneWayB}}',
           changeDetection: ChangeDetectionStrategy.OnPush
         })

         class Ng2Component {
           ngOnChangesCount = 0;
           oneWayB = '?';
         }

         ng1Module.directive('ng2', downgradeComponent({
                               component: Ng2Component,
                             }));

         @NgModule({
           declarations: [Ng2Component],
           entryComponents: [Ng2Component],
           imports: [BrowserModule, UpgradeModule]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const element = html(`
          <div>
            <ng2 [one-way-b]="dataB"></ng2>
          </div>`);

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then((upgrade) => {
           expect(multiTrim(document.body.textContent)).toEqual('oneWayB: B');
           $apply(upgrade, 'dataB= "everyone"');
           expect(multiTrim(document.body.textContent)).toEqual('oneWayB: everyone');
         });
       }));

    it('should support two-way binding and event listener', async(() => {
         const listenerSpy = jasmine.createSpy('$rootScope.listener');
         const ng1Module = angular.module_('ng1', []).run(($rootScope: angular.IScope) => {
           $rootScope['value'] = 'world';
           $rootScope['listener'] = listenerSpy;
         });

         @Component({selector: 'ng2', template: `model: {{model}};`})
         class Ng2Component implements OnChanges {
           ngOnChangesCount = 0;
           @Input() model = '?';
           @Output() modelChange = new EventEmitter();

           ngOnChanges(changes: SimpleChanges) {
             switch (this.ngOnChangesCount++) {
               case 0:
                 expect(changes.model.currentValue).toBe('world');
                 this.modelChange.emit('newC');
                 break;
               case 1:
                 expect(changes.model.currentValue).toBe('newC');
                 break;
               default:
                 throw new Error('Called too many times! ' + JSON.stringify(changes));
             }
           }
         }

         ng1Module.directive('ng2', downgradeComponent({component: Ng2Component}));

         @NgModule({
           declarations: [Ng2Component],
           entryComponents: [Ng2Component],
           imports: [BrowserModule, UpgradeModule]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const element = html(`
          <div>
            <ng2 [(model)]="value" (model-change)="listener($event)"></ng2>
            | value: {{value}}
          </div>
        `);

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then((upgrade) => {
           expect(multiTrim(element.textContent)).toEqual('model: newC; | value: newC');
           expect(listenerSpy).toHaveBeenCalledWith('newC');
         });
       }));

    it('should run change-detection on every digest (by default)', async(() => {
         let ng2Component: Ng2Component;

         @Component({selector: 'ng2', template: '{{ value1 }} | {{ value2 }}'})
         class Ng2Component {
           @Input() value1 = -1;
           @Input() value2 = -1;

           constructor() { ng2Component = this; }
         }

         @NgModule({
           imports: [BrowserModule, UpgradeModule],
           declarations: [Ng2Component],
           entryComponents: [Ng2Component]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module = angular.module_('ng1', [])
                               .directive('ng2', downgradeComponent({component: Ng2Component}))
                               .run(($rootScope: angular.IRootScopeService) => {
                                 $rootScope.value1 = 0;
                                 $rootScope.value2 = 0;
                               });

         const element = html('<ng2 [value1]="value1" value2="{{ value2 }}"></ng2>');

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then(upgrade => {
           const $rootScope = upgrade.$injector.get('$rootScope') as angular.IRootScopeService;

           expect(element.textContent).toBe('0 | 0');

           // Digest should invoke CD
           $rootScope.$digest();
           $rootScope.$digest();
           expect(element.textContent).toBe('0 | 0');

           // Internal changes should be detected on digest
           ng2Component.value1 = 1;
           ng2Component.value2 = 2;
           $rootScope.$digest();
           expect(element.textContent).toBe('1 | 2');

           // Digest should propagate change in prop-bound input
           $rootScope.$apply('value1 = 3');
           expect(element.textContent).toBe('3 | 2');

           // Digest should propagate change in attr-bound input
           ng2Component.value1 = 4;
           $rootScope.$apply('value2 = 5');
           expect(element.textContent).toBe('4 | 5');

           // Digest should propagate changes that happened before the digest
           $rootScope.value1 = 6;
           expect(element.textContent).toBe('4 | 5');

           $rootScope.$digest();
           expect(element.textContent).toBe('6 | 5');
         });
       }));

    it('should not run change-detection on every digest when opted out', async(() => {
         let ng2Component: Ng2Component;

         @Component({selector: 'ng2', template: '{{ value1 }} | {{ value2 }}'})
         class Ng2Component {
           @Input() value1 = -1;
           @Input() value2 = -1;

           constructor() { ng2Component = this; }
         }

         @NgModule({
           imports: [BrowserModule, UpgradeModule],
           declarations: [Ng2Component],
           entryComponents: [Ng2Component]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module =
             angular.module_('ng1', [])
                 .directive(
                     'ng2', downgradeComponent({component: Ng2Component, propagateDigest: false}))
                 .run(($rootScope: angular.IRootScopeService) => {
                   $rootScope.value1 = 0;
                   $rootScope.value2 = 0;
                 });

         const element = html('<ng2 [value1]="value1" value2="{{ value2 }}"></ng2>');

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then(upgrade => {
           const $rootScope = upgrade.$injector.get('$rootScope') as angular.IRootScopeService;

           expect(element.textContent).toBe('0 | 0');

           // Digest should not invoke CD
           $rootScope.$digest();
           $rootScope.$digest();
           expect(element.textContent).toBe('0 | 0');

           // Digest should not invoke CD, even if component values have changed (internally)
           ng2Component.value1 = 1;
           ng2Component.value2 = 2;
           $rootScope.$digest();
           expect(element.textContent).toBe('0 | 0');

           // Digest should invoke CD, if prop-bound input has changed
           $rootScope.$apply('value1 = 3');
           expect(element.textContent).toBe('3 | 2');

           // Digest should invoke CD, if attr-bound input has changed
           ng2Component.value1 = 4;
           $rootScope.$apply('value2 = 5');
           expect(element.textContent).toBe('4 | 5');

           // Digest should invoke CD, if input has changed before the digest
           $rootScope.value1 = 6;
           $rootScope.$digest();
           expect(element.textContent).toBe('6 | 5');
         });
       }));

    it('should still run normal Angular change-detection regardless of `propagateDigest`',
       fakeAsync(() => {
         let ng2Component: Ng2Component;

         @Component({selector: 'ng2', template: '{{ value }}'})
         class Ng2Component {
           value = 'foo';
           constructor() { setTimeout(() => this.value = 'bar', 1000); }
         }

         @NgModule({
           imports: [BrowserModule, UpgradeModule],
           declarations: [Ng2Component],
           entryComponents: [Ng2Component]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module =
             angular.module_('ng1', [])
                 .directive(
                     'ng2A', downgradeComponent({component: Ng2Component, propagateDigest: true}))
                 .directive(
                     'ng2B', downgradeComponent({component: Ng2Component, propagateDigest: false}));

         const element = html('<ng2-a></ng2-a> | <ng2-b></ng2-b>');

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then(upgrade => {
           expect(element.textContent).toBe('foo | foo');

           tick(1000);
           expect(element.textContent).toBe('bar | bar');
         });
       }));

    it('should initialize inputs in time for `ngOnChanges`', async(() => {
         @Component({
           selector: 'ng2',
           template: `
             ngOnChangesCount: {{ ngOnChangesCount }} |
             firstChangesCount: {{ firstChangesCount }} |
             initialValue: {{ initialValue }}`
         })
         class Ng2Component implements OnChanges {
           ngOnChangesCount = 0;
           firstChangesCount = 0;
           // TODO(issue/24571): remove '!'.
           initialValue !: string;
           // TODO(issue/24571): remove '!'.
           @Input() foo !: string;

           ngOnChanges(changes: SimpleChanges) {
             this.ngOnChangesCount++;

             if (this.ngOnChangesCount === 1) {
               this.initialValue = this.foo;
             }

             if (changes['foo'] && changes['foo'].isFirstChange()) {
               this.firstChangesCount++;
             }
           }
         }

         @NgModule({
           imports: [BrowserModule, UpgradeModule],
           declarations: [Ng2Component],
           entryComponents: [Ng2Component]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module = angular.module_('ng1', []).directive(
             'ng2', downgradeComponent({component: Ng2Component}));

         const element = html(`
           <ng2 [foo]="'foo'"></ng2>
           <ng2 foo="bar"></ng2>
           <ng2 [foo]="'baz'" ng-if="true"></ng2>
           <ng2 foo="qux" ng-if="true"></ng2>
         `);

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then(upgrade => {
           const nodes = element.querySelectorAll('ng2');
           const expectedTextWith = (value: string) =>
               `ngOnChangesCount: 1 | firstChangesCount: 1 | initialValue: ${value}`;

           expect(multiTrim(nodes[0].textContent)).toBe(expectedTextWith('foo'));
           expect(multiTrim(nodes[1].textContent)).toBe(expectedTextWith('bar'));
           expect(multiTrim(nodes[2].textContent)).toBe(expectedTextWith('baz'));
           expect(multiTrim(nodes[3].textContent)).toBe(expectedTextWith('qux'));
         });
       }));

    it('should bind to ng-model', async(() => {
         const ng1Module = angular.module_('ng1', []).run(
             ($rootScope: angular.IScope) => { $rootScope['modelA'] = 'A'; });

         let ng2Instance: Ng2;
         @Component({selector: 'ng2', template: '<span>{{_value}}</span>'})
         class Ng2 {
           private _value: any = '';
           private _onChangeCallback: (_: any) => void = () => {};
           private _onTouchedCallback: () => void = () => {};
           constructor() { ng2Instance = this; }
           writeValue(value: any) { this._value = value; }
           registerOnChange(fn: any) { this._onChangeCallback = fn; }
           registerOnTouched(fn: any) { this._onTouchedCallback = fn; }
           doTouch() { this._onTouchedCallback(); }
           doChange(newValue: string) {
             this._value = newValue;
             this._onChangeCallback(newValue);
           }
         }

         ng1Module.directive('ng2', downgradeComponent({component: Ng2}));

         const element = html(`<div><ng2 ng-model="modelA"></ng2> | {{modelA}}</div>`);

         @NgModule(
             {declarations: [Ng2], entryComponents: [Ng2], imports: [BrowserModule, UpgradeModule]})
         class Ng2Module {
           ngDoBootstrap() {}
         }

         platformBrowserDynamic().bootstrapModule(Ng2Module).then((ref) => {
           const adapter = ref.injector.get(UpgradeModule) as UpgradeModule;
           adapter.bootstrap(element, [ng1Module.name]);
           const $rootScope = adapter.$injector.get('$rootScope');

           expect(multiTrim(document.body.textContent)).toEqual('A | A');

           $rootScope.modelA = 'B';
           $rootScope.$apply();
           expect(multiTrim(document.body.textContent)).toEqual('B | B');

           ng2Instance.doChange('C');
           expect($rootScope.modelA).toBe('C');
           expect(multiTrim(document.body.textContent)).toEqual('C | C');

           const downgradedElement = <Element>document.body.querySelector('ng2');
           expect(downgradedElement.classList.contains('ng-touched')).toBe(false);

           ng2Instance.doTouch();
           $rootScope.$apply();
           expect(downgradedElement.classList.contains('ng-touched')).toBe(true);
         });
       }));

    it('should properly run cleanup when ng1 directive is destroyed', async(() => {

         let destroyed = false;
         @Component({selector: 'ng2', template: 'test'})
         class Ng2Component implements OnDestroy {
           ngOnDestroy() { destroyed = true; }
         }

         @NgModule({
           declarations: [Ng2Component],
           entryComponents: [Ng2Component],
           imports: [BrowserModule, UpgradeModule]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module =
             angular.module_('ng1', [])
                 .directive(
                     'ng1',
                     () => { return {template: '<div ng-if="!destroyIt"><ng2></ng2></div>'}; })
                 .directive('ng2', downgradeComponent({component: Ng2Component}));
         const element = html('<ng1></ng1>');
         platformBrowserDynamic().bootstrapModule(Ng2Module).then((ref) => {
           const adapter = ref.injector.get(UpgradeModule) as UpgradeModule;
           adapter.bootstrap(element, [ng1Module.name]);
           expect(element.textContent).toContain('test');
           expect(destroyed).toBe(false);

           const $rootScope = adapter.$injector.get('$rootScope');
           $rootScope.$apply('destroyIt = true');

           expect(element.textContent).not.toContain('test');
           expect(destroyed).toBe(true);
         });
       }));

    it('should properly run cleanup with multiple levels of nesting', async(() => {
         let destroyed = false;

         @Component({
           selector: 'ng2-outer',
           template: '<div *ngIf="!destroyIt"><ng1></ng1></div>',
         })
         class Ng2OuterComponent {
           @Input() destroyIt = false;
         }

         @Component({selector: 'ng2-inner', template: 'test'})
         class Ng2InnerComponent implements OnDestroy {
           ngOnDestroy() { destroyed = true; }
         }

         @Directive({selector: 'ng1'})
         class Ng1ComponentFacade extends UpgradeComponent {
           constructor(elementRef: ElementRef, injector: Injector) {
             super('ng1', elementRef, injector);
           }
         }

         @NgModule({
           imports: [BrowserModule, UpgradeModule],
           declarations: [Ng1ComponentFacade, Ng2InnerComponent, Ng2OuterComponent],
           entryComponents: [Ng2InnerComponent, Ng2OuterComponent],
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module =
             angular.module_('ng1', [])
                 .directive('ng1', () => ({template: '<ng2-inner></ng2-inner>'}))
                 .directive('ng2Inner', downgradeComponent({component: Ng2InnerComponent}))
                 .directive('ng2Outer', downgradeComponent({component: Ng2OuterComponent}));

         const element = html('<ng2-outer [destroy-it]="destroyIt"></ng2-outer>');

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then(upgrade => {
           expect(element.textContent).toBe('test');
           expect(destroyed).toBe(false);

           $apply(upgrade, 'destroyIt = true');

           expect(element.textContent).toBe('');
           expect(destroyed).toBe(true);
         });
       }));

    it('should work when compiled outside the dom (by fallback to the root ng2.injector)',
       async(() => {

         @Component({selector: 'ng2', template: 'test'})
         class Ng2Component {
         }

         @NgModule({
           declarations: [Ng2Component],
           entryComponents: [Ng2Component],
           imports: [BrowserModule, UpgradeModule]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module =
             angular.module_('ng1', [])
                 .directive(
                     'ng1',
                     [
                       '$compile',
                       ($compile: angular.ICompileService) => {
                         return {
                           link: function(
                               $scope: angular.IScope, $element: angular.IAugmentedJQuery,
                               $attrs: angular.IAttributes) {
                             // here we compile some HTML that contains a downgraded component
                             // since it is not currently in the DOM it is not able to "require"
                             // an ng2 injector so it should use the `moduleInjector` instead.
                             const compiled = $compile('<ng2></ng2>');
                             const template = compiled($scope);
                             $element.append !(template);
                           }
                         };
                       }
                     ])
                 .directive('ng2', downgradeComponent({component: Ng2Component}));

         const element = html('<ng1></ng1>');
         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then((upgrade) => {
           // the fact that the body contains the correct text means that the
           // downgraded component was able to access the moduleInjector
           // (since there is no other injector in this system)
           expect(multiTrim(document.body.textContent)).toEqual('test');
         });
       }));

    it('should allow attribute selectors for downgraded components', async(() => {
         @Component({selector: '[itWorks]', template: 'It works'})
         class WorksComponent {
         }

         @NgModule({
           declarations: [WorksComponent],
           entryComponents: [WorksComponent],
           imports: [BrowserModule, UpgradeModule]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module = angular.module_('ng1', []).directive(
             'worksComponent', downgradeComponent({component: WorksComponent}));

         const element = html('<works-component></works-component>');

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then((upgrade) => {
           expect(multiTrim(document.body.textContent)).toBe('It works');
         });
       }));

    it('should allow attribute selectors for components in ng2', async(() => {
         @Component({selector: '[itWorks]', template: 'It works'})
         class WorksComponent {
         }

         @Component({selector: 'root-component', template: '<span itWorks></span>!'})
         class RootComponent {
         }

         @NgModule({
           declarations: [RootComponent, WorksComponent],
           entryComponents: [RootComponent],
           imports: [BrowserModule, UpgradeModule]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module = angular.module_('ng1', []).directive(
             'rootComponent', downgradeComponent({component: RootComponent}));

         const element = html('<root-component></root-component>');

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then((upgrade) => {
           expect(multiTrim(document.body.textContent)).toBe('It works!');
         });
       }));

    it('should respect hierarchical dependency injection for ng2', async(() => {
         @Component({selector: 'parent', template: 'parent(<ng-content></ng-content>)'})
         class ParentComponent {
         }

         @Component({selector: 'child', template: 'child'})
         class ChildComponent {
           constructor(parent: ParentComponent) {}
         }

         @NgModule({
           declarations: [ParentComponent, ChildComponent],
           entryComponents: [ParentComponent, ChildComponent],
           imports: [BrowserModule, UpgradeModule]
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module =
             angular.module_('ng1', [])
                 .directive('parent', downgradeComponent({component: ParentComponent}))
                 .directive('child', downgradeComponent({component: ChildComponent}));

         const element = html('<parent><child></child></parent>');

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then(upgrade => {
           expect(multiTrim(document.body.textContent)).toBe('parent(child)');
         });
       }));

    it('should be compiled synchronously, if possible', async(() => {
         @Component({selector: 'ng2A', template: '<ng-content></ng-content>'})
         class Ng2ComponentA {
         }

         @Component({selector: 'ng2B', template: '{{ \'Ng2 template\' }}'})
         class Ng2ComponentB {
         }

         @NgModule({
           declarations: [Ng2ComponentA, Ng2ComponentB],
           entryComponents: [Ng2ComponentA, Ng2ComponentB],
           imports: [BrowserModule, UpgradeModule],
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         const ng1Module = angular.module_('ng1', [])
                               .directive('ng2A', downgradeComponent({component: Ng2ComponentA}))
                               .directive('ng2B', downgradeComponent({component: Ng2ComponentB}));

         const element = html('<ng2-a><ng2-b></ng2-b></ng2-a>');

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then(() => {
           expect(element.textContent).toBe('Ng2 template');
         });
       }));

    it('should work with ng2 lazy loaded components', async(() => {
         let componentInjector: Injector;

         @Component({selector: 'ng2', template: ''})
         class Ng2Component {
           constructor(injector: Injector) { componentInjector = injector; }
         }

         @NgModule({
           declarations: [Ng2Component],
           entryComponents: [Ng2Component],
           imports: [BrowserModule, UpgradeModule],
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }

         @Component({template: ''})
         class LazyLoadedComponent {
           constructor(public module: NgModuleRef<any>) {}
         }

         @NgModule({
           declarations: [LazyLoadedComponent],
           entryComponents: [LazyLoadedComponent],
         })
         class LazyLoadedModule {
         }

         const ng1Module = angular.module_('ng1', []).directive(
             'ng2', downgradeComponent({component: Ng2Component}));

         const element = html('<ng2></ng2>');

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module).then(upgrade => {
           const modInjector = upgrade.injector;
           // Emulate the router lazy loading a module and creating a component
           const compiler = modInjector.get(Compiler);
           const modFactory = compiler.compileModuleSync(LazyLoadedModule);
           const childMod = modFactory.create(modInjector);
           const cmpFactory =
               childMod.componentFactoryResolver.resolveComponentFactory(LazyLoadedComponent) !;
           const lazyCmp = cmpFactory.create(componentInjector);

           expect(lazyCmp.instance.module.injector === childMod.injector).toBe(true);
         });

       }));

    it('should throw if `downgradedModule` is specified', async(() => {
         @Component({selector: 'ng2', template: ''})
         class Ng2Component {
         }

         @NgModule({
           declarations: [Ng2Component],
           entryComponents: [Ng2Component],
           imports: [BrowserModule, UpgradeModule],
         })
         class Ng2Module {
           ngDoBootstrap() {}
         }


         const ng1Module = angular.module_('ng1', []).directive(
             'ng2', downgradeComponent({component: Ng2Component, downgradedModule: 'foo'}));

         const element = html('<ng2></ng2>');

         bootstrap(platformBrowserDynamic(), Ng2Module, element, ng1Module)
             .then(
                 () => { throw new Error('Expected bootstraping to fail.'); },
                 err =>
                     expect(err.message)
                         .toBe(
                             'Error while instantiating component \'Ng2Component\': \'downgradedModule\' ' +
                             'unexpectedly specified.\n' +
                             'You should not specify a value for \'downgradedModule\', unless you are ' +
                             'downgrading more than one Angular module (via \'downgradeModule()\').'));
       }));
  });
});