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π¦ π A Powerful Tool to Simplify Your Angular Tests
A Powerful Tool to Simplify Your Angular Tests
Spectator helps you get rid of all the boilerplate grunt work, leaving you with readable, sleek and streamlined unit tests.
Features
- β Support for testing Angular components, directives and services
- β Easy DOM querying
- β Clean API for triggering keyboard/mouse/touch events
- β
Testing
ng-content
- β Custom Jasmine/Jest Matchers (toHaveClass, toBeDisabled..)
- β Routing testing support
- β HTTP testing support
- β Built-in support for entry components
- β Built-in support for component providers
- β Auto-mocking providers
- β Strongly typed
- β Jest Support
Table of Contents
- Features
- Table of Contents
-
Installation
- NPM
- Yarn
-
Testing Components
-
Events API
- Custom Events
- Event Creators
- Keyboard helpers
- Mouse helpers
-
Queries
- String Selector
- Type Selector
- DOM Selector
- Testing Select Elements
- Mocking Components
- Testing Single Component/Directive Angular Modules
-
Events API
-
Testing with Host
- Custom Host Component
-
Testing with Routing
- Triggering a navigation
-
Integration testing with
RouterTestingModule
- Routing Options
- Testing Directives
-
Testing Services
- Additional Options
-
Testing Pipes
- Using Custom Host Component
-
Mocking Providers
- Mocking OnInit Dependencies
- Mocking Constructor Dependencies
- Jest Support
- Testing with HTTP
- Global Injections
- Component Providers
- Custom Matchers
- Schematics
- Default Schematics Collection
- Working Spectator & Jest Sample Repo and Karma Comparison
- Core Team
- Contributors
Installation
NPM
npm install @ngneat/spectator --save-dev
Yarn
yarn add @ngneat/spectator --dev
Testing Components
Create a component factory by using the createComponentFactory()
function, passing the component class that you want to test.
The createComponentFactory()
returns a function that will create a fresh component in each it
block:
import { Spectator, createComponentFactory } from '@ngneat/spectator';
import { ButtonComponent } from './button.component';
describe('ButtonComponent', () => {
let spectator: Spectator<ButtonComponent>;
const createComponent = createComponentFactory(ButtonComponent);
beforeEach(() => spectator = createComponent());
it('should have a success class by default', () => {
expect(spectator.query('button')).toHaveClass('success');
});
it('should set the class name according to the [className] input', () => {
spectator.setInput('className', 'danger');
expect(spectator.query('button')).toHaveClass('danger');
expect(spectator.query('button')).not.toHaveClass('success');
});
});
The createComponentFactory
function can optionally take the following options which extends the basic Angular Testing Module options:
const createComponent = createComponentFactory({
component: ButtonComponent,
imports: [],
providers: [],
declarations: [],
entryComponents: [],
componentProviders: [], // Override the component's providers
componentViewProviders: [], // Override the component's view providers
overrideModules: [], // Override modules
mocks: [], // Providers that will automatically be mocked
componentMocks: [], // Component providers that will automatically be mocked
componentViewProvidersMocks: [], // Component view providers that will be automatically mocked
detectChanges: false, // Defaults to true
declareComponent: false, // Defaults to true
disableAnimations: false, // Defaults to true
shallow: true, // Defaults to false
});
The createComponent()
function optionally takes the following options:
it('should...', () => {
spectator = createComponent({
// The component inputs
props: {
title: 'Click'
},
// Override the component's providers
// Note that you must declare it once in `createComponentFactory`
providers: [],
// Whether to run change detection (defaults to true)
detectChanges: false
});
expect(spectator.query('button')).toHaveText('Click');
});
The createComponent()
method returns an instance of Spectator
which exposes the following API:
-
fixture
- The tested component's fixture -
component
- The tested component's instance -
element
- The tested component's native element -
debugElement
- The tested fixture's debug element -
inject()
- Provides a wrapper forTestBed.inject()
:
const service = spectator.inject(QueryService);
const fromComponentInjector = true;
const service = spectator.inject(QueryService, fromComponentInjector);
-
detectChanges()
- Runs detectChanges on the tested element/host:
spectator.detectChanges();
-
detectComponentChanges()
- RunsdetectChanges
on the tested component ( not on thehost
). You'll need this method in rare cases when using ahost
and the tested component isonPush
, and you want to force it to run a change detection cycle.
spectator.detectComponentChanges();
-
setInput()
- Changes the value of an @Input() of the tested component. Method runsngOnChanges
withSimpleChanges
manually if it exists.
it('should...', () => {
spectator.setInput('className', 'danger');
spectator.setInput({
className: 'danger'
});
});
-
output
- Returns an Observable @Output() of the tested component:
it('should emit the $event on click', () => {
let output;
spectator.output('click').subscribe(result => (output = result));
spectator.component.onClick({ type: 'click' });
expect(output).toEqual({ type: 'click' });
});
-
tick(millis?: number)
- Run the fakeAsynctick()
function and calldetectChanges()
:
it('should work with tick', fakeAsync(() => {
spectator = createComponent(ZippyComponent);
spectator.component.update();
expect(spectator.component.updatedAsync).toBeFalsy();
spectator.tick(6000);
expect(spectator.component.updatedAsync).not.toBeFalsy();
}))
Events API
Each one of the events can accept a SpectatorElement
which can be one of the following:
type SpectatorElement = string | Element | DebugElement | ElementRef | Window | Document | DOMSelector;
If not provided, the default element will be the host element of the component under test.
-
click()
- Triggers a click event:
spectator.click(SpectatorElement);
spectator.click(byText('Element'));
-
blur()
- Triggers a blur event:
spectator.blur(SpectatorElement);
spectator.blur(byText('Element'));
Note that if using the jest framework, blur() only works if the element is focused. Details.
-
focus()
- Triggers a focus event:
spectator.focus(SpectatorElement);
spectator.focus(byText('Element'));
-
typeInElement()
- Simulating the user typing:
spectator.typeInElement(value, SpectatorElement);
spectator.typeInElement(value, byText('Element'));
-
dispatchMouseEvent()
- Triggers a mouse event:
spectator.dispatchMouseEvent(SpectatorElement, 'mouseout');
spectator.dispatchMouseEvent(SpectatorElement, 'mouseout'), x, y, event);
spectator.dispatchMouseEvent(byText('Element'), 'mouseout');
spectator.dispatchMouseEvent(byText('Element'), 'mouseout', x, y, event);
-
dispatchKeyboardEvent()
- Triggers a keyboard event:
spectator.dispatchKeyboardEvent(SpectatorElement, 'keyup', 'Escape');
spectator.dispatchKeyboardEvent(SpectatorElement, 'keyup', { key: 'Escape', keyCode: 27 })
spectator.dispatchKeyboardEvent(byText('Element'), 'keyup', 'Escape');
spectator.dispatchKeyboardEvent(byText('Element'), 'keyup', { key: 'Escape', keyCode: 27 })
-
dispatchTouchEvent()
- Triggers a touch event:
spectator.dispatchTouchEvent(SpectatorElement, type, x, y);
spectator.dispatchTouchEvent(byText('Element'), type, x, y);
Custom Events
You can trigger custom events (@Output() of child components) using the following method:
spectator.triggerEventHandler(MyChildComponent, 'myCustomEvent', 'eventValue');
spectator.triggerEventHandler(MyChildComponent, 'myCustomEvent', 'eventValue', { root: true});
spectator.triggerEventHandler('app-child-component', 'myCustomEvent', 'eventValue');
spectator.triggerEventHandler('app-child-component', 'myCustomEvent', 'eventValue', { root: true});
Event Creators
In case you want to test events independently of any template (e.g. in presenter services) you can fallback on the underlying event creators. They are basically providing the same signature without the preceding element.
const keyboardEvent = createKeyboardEvent('keyup', 'ArrowDown'/*, targetElement */);
const mouseEvent = createMouseEvent('mouseout');
const touchEvent = createTouchEvent('touchmove');
const fakeEvent = createFakeEvent('input');
Keyboard helpers
spectator.keyboard.pressEnter();
spectator.keyboard.pressEscape();
spectator.keyboard.pressTab();
spectator.keyboard.pressBackspace();
spectator.keyboard.pressKey('a');
spectator.keyboard.pressKey('ctrl.a');
spectator.keyboard.pressKey('ctrl.shift.a');
Mouse helpers
spectator.mouse.contextmenu('.selector');
spectator.mouse.dblclick('.selector');
Note that each one of the above methods will also run detectChanges()
.
Queries
The Spectator API includes convenient methods for querying the DOM as part of a test: query
, queryAll
, queryLast
, queryHost
and queryHostAll
. All query methods are polymorphic and allow you to query using any of the following techniques.
String Selector
Pass a string selector (in the same style as you would when using jQuery or document.querySelector) to query for elements that match that path in the DOM. This method for querying is equivalent to Angular's By.css predicate. Note that native HTML elements will be returned. For example:
// Returns a single HTMLElement
spectator.query('div > ul.nav li:first-child');
// Returns an array of all matching HTMLElements
spectator.queryAll('div > ul.nav li');
// Query from the document context
spectator.query('div', { root: true });
spectator.query('app-child', { read: ChildServiceService });
Type Selector
Pass a type (such as a component, directive or provider class) to query for instances of that type in the DOM. This is equivalent to Angular's By.directive
predicate. You can optionally pass in a second parameter to read a specific injection token from the matching elements' injectors. For example:
// Returns a single instance of MyComponent (if present)
spectator.query(MyComponent);
// Returns the instance of `SomeService` found in the instance of `MyComponent` that exists in the DOM (if present)
spectator.query(MyComponent, { read: SomeService });
spectator.query(MyComponent, { read: ElementRef });
host.queryLast(ChildComponent);
host.queryAll(ChildComponent);
DOM Selector
Spectator allows you to query for elements using selectors inspired by dom-testing-library. The available selectors are:
spectator.query(byPlaceholder('Please enter your email address'));
spectator.query(byValue('By value'));
spectator.query(byTitle('By title'));
spectator.query(byAltText('By alt text'));
spectator.query(byLabel('By label'));
spectator.query(byText('By text'));
spectator.query(byText('By text', {selector: '#some .selector'}));
spectator.query(byTextContent('By text content', {selector: '#some .selector'}));
spectator.query(byRole('checkbox', { checked: true }));
The difference between byText
and byTextContent
is that the former doesn't match text inside a nested elements.
For example, in this following HTML byText('foobar', {selector: 'div'})
won't match the following div
, but byTextContent
will:
<div>
<span>foo</span>
<span>bar</span>
</div>
Testing Select Elements
Spectator allows you to test <select></select>
elements easily, and supports multi select.
Example:
it('should set the correct options on multi select', () => {
const select = spectator.query('#test-multi-select') as HTMLSelectElement;
spectator.selectOption(select, ['1', '2']);
expect(select).toHaveSelectedOptions(['1', '2']);
});
it('should set the correct option on standard select', () => {
const select = spectator.query('#test-single-select') as HTMLSelectElement;
spectator.selectOption(select, '1');
expect(select).toHaveSelectedOptions('1');
});
It also allows you to check if your change
event handler is acting correctly for each item selected. You can disable this if you need to pre set choices without dispatching the change event.
API:
spectator.selectOption(selectElement: HTMLSelectElement, options: string | string[] | HTMLOptionElement | HTMLOptionElement[], config: { emitEvents: boolean } = { emitEvents: true });
Example:
it('should dispatch correct number of change events', () => {
const onChangeSpy = spyOn(spectator.component, 'handleChange');
const select = spectator.query('#test-onchange-select') as HTMLSelectElement;
spectator.selectOption(select, ['1', '2'], { emitEvents: true});
expect(select).toHaveSelectedOptions(['1', '2']);
expect(onChangeSpy).toHaveBeenCalledTimes(2);
});
it('should not dispatch correct number of change events', () => {
const onChangeSpy = spyOn(spectator.component, 'handleChange');
const select = spectator.query('#test-onchange-select') as HTMLSelectElement;
spectator.selectOption(select, ['1', '2'], { emitEvents: false});
expect(select).toHaveSelectedOptions(['1', '2']);
expect(onChangeSpy).not.toHaveBeenCalledTimes(2);
});
You can also pass HTMLOptionElement
(s) as arguments to selectOption
and the toHaveSelectedOptions
matcher. This is particularly useful when you are using [ngValue]
binding on the <option>
:
it('should set the correct option on single select when passing the element', () => {
const select = spectator.query('#test-single-select-element') as HTMLSelectElement;
spectator.selectOption(select, spectator.query(byText('Two')) as HTMLOptionElement);
expect(select).toHaveSelectedOptions(spectator.query(byText('Two')) as HTMLOptionElement);
});
Mocking Components
If you need to mock components, you can use the ng-mocks library. Instead of using CUSTOM_ELEMENTS_SCHEMA
,which might hide some issues and won't help you to set inputs, outputs, etc., ng-mocks
will auto mock the inputs, outputs, etc. for you.
Example:
import { createHostFactory } from '@ngneat/spectator';
import { MockComponent } from 'ng-mocks';
import { FooComponent } from './path/to/foo.component';
const createHost = createHostFactory({
component: YourComponentToTest,
declarations: [
MockComponent(FooComponent)
]
});
Testing Single Component/Directive Angular Modules
Components (or Directives) that are declared in their own module can be tested by defining the component module in the imports list of the component factory together with the component. For example:
const createComponent = createComponentFactory({
component: ButtonComponent,
imports: [ButtonComponentModule],
});
When used like this, however, Spectator internally adds the component ButtonComponent
to the declarations of the internally created new module. Hence, you will see the following error:
Type ButtonComponent is part of the declarations of 2 modules [...]
It is possible to tell Spectator not to add the component to the declarations of the internal module and, instead, use the explicitly defined module as is. Simply set the declareComponent
property of the factory options to false
:
const createComponent = createComponentFactory({
component: ButtonComponent,
imports: [ButtonComponentModule],
declareComponent: false,
});
When using createDirectiveFactory set the declareDirective
property of the factory options to false
:
const createDirective = createDirectiveFactory({
component: HighlightComponent,
imports: [HighlightComponentModule],
declareDirective: false,
});
Testing with Host
Testing a component with a host component is a more elegant and powerful technique to test your component. It basically gives you the ability to write your tests in the same way that you write your code. Let's see it in action:
import { createHostFactory, SpectatorHost } from '@ngneat/spectator';
describe('ZippyComponent', () => {
let spectator: SpectatorHost<ZippyComponent>;
const createHost = createHostFactory(ZippyComponent);
it('should display the title from host property', () => {
spectator = createHost(`<zippy [title]="title"></zippy>`, {
hostProps: {
title: 'Spectator is Awesome'
}
});
expect(spectator.query('.zippy__title')).toHaveText('Spectator is Awesome');
});
it('should display the "Close" word if open', () => {
spectator = createHost(`<zippy title="Zippy title">Zippy content</zippy>`);
spectator.click('.zippy__title');
expect(spectator.query('.arrow')).toHaveText('Close');
expect(spectator.query('.arrow')).not.toHaveText('Open');
});
});
The host method returns an instance of SpectatorHost
which extends Spectator
with the following additional API:
-
hostFixture
- The host's fixture -
hostComponent
- The host's component instance -
hostElement
- The host's native element -
hostDebugElement
- The host's fixture debug element -
setHostInput
- Changes the value of an@Input()
of the host component -
queryHost
- Read more about querying in Spectator -
queryHostAll
- Read more about querying in Spectator
Custom Host Component
Sometimes it's helpful to pass your own host implementation. We can pass a custom host component to the createHostFactory()
that will replace the default one:
@Component({ selector: 'custom-host', template: '' })
class CustomHostComponent {
title = 'Custom HostComponent';
}
describe('With Custom Host Component', function () {
let spectator: SpectatorHost<ZippyComponent, CustomHostComponent>;
const createHost = createHostFactory({
component: ZippyComponent,
host: CustomHostComponent
});
it('should display the host component title', () => {
spectator = createHost(`<zippy [title]="title"></zippy>`);
expect(spectator.query('.zippy__title')).toHaveText('Custom HostComponent');
});
});
Testing with Routing
For components which use routing, there is a special factory available that extends the default one, and provides a stubbed ActivatedRoute
so that you can configure additional routing options.
describe('ProductDetailsComponent', () => {
let spectator: SpectatorRouting<ProductDetailsComponent>;
const createComponent = createRoutingFactory({
component: ProductDetailsComponent,
params: { productId: '3' },
data: { title: 'Some title' }
});
beforeEach(() => spectator = createComponent());
it('should display route data title', () => {
expect(spectator.query('.title')).toHaveText('Some title');
});
it('should react to route changes', () => {
spectator.setRouteParam('productId', '5');
// your test here...
});
});
Triggering a navigation
The SpectatorRouting
API includes convenient methods for updating the current route:
interface SpectatorRouting<C> extends Spectator<C> {
/**
* Simulates a route navigation by updating the Params, QueryParams and Data observable streams.
*/
triggerNavigation(options?: RouteOptions): void;
/**
* Updates the route params and triggers a route navigation.
*/
setRouteParam(name: string, value: string): void;
/**
* Updates the route query params and triggers a route navigation.
*/
setRouteQueryParam(name: string, value: string): void;
/**
* Updates the route data and triggers a route navigation.
*/
setRouteData(name: string, value: any): void;
/**
* Updates the route fragment and triggers a route navigation.
*/
setRouteFragment(fragment: string | null): void;
/**
* Updates the route url and triggers a route navigation.
*/
setRouteUrl(url: UrlSegment[]): void;
}
Integration testing with RouterTestingModule
If you set the stubsEnabled
option to false
, you can pass a real routing configuration
and setup an integration test using the RouterTestingModule
from Angular.
Note that this requires promises to resolve. One way to deal with this, is by making your test async:
describe('Routing integration test', () => {
const createComponent = createRoutingFactory({
component: MyComponent,
declarations: [OtherComponent],
stubsEnabled: false,
routes: [
{
path: '',
component: MyComponent
},
{
path: 'foo',
component: OtherComponent
}
]
});
it('should navigate away using router link', async () => {
const spectator = createComponent();
// wait for promises to resolve...
await spectator.fixture.whenStable();
// test the current route by asserting the location
expect(spectator.inject(Location).path()).toBe('/');
// click on a router link
spectator.click('.link-1');
// don't forget to wait for promises to resolve...
await spectator.fixture.whenStable();
// test the new route by asserting the location
expect(spectator.inject(Location).path()).toBe('/foo');
});
});
Routing Options
The createRoutesFactory
function can take the following options, on top of the default Spectator options:
-
params
: initial params to use inActivatedRoute
stub -
queryParams
: initial query params to use inActivatedRoute
stub -
data
: initial data to use inActivatedRoute
stub -
fragment
: initial fragment to use inActivatedRoute
stub -
url
: initial URL segments to use inActivatedRoute
stub -
root
: the value forroot
for theActivatedRoute
stub -
parent
: the value forparent
for theActivatedRoute
stub -
children
: the value forchildren
for theActivatedRoute
stub -
firstChild
: the value forfirstChild
for theActivatedRoute
stub -
stubsEnabled
(default:true
): enables theActivatedRoute
stub, if set tofalse
it usesRouterTestingModule
instead -
routes
: ifstubsEnabled
is set to false, you can pass aRoutes
configuration forRouterTestingModule
Testing Directives
There is a special test factory for testing directives. Let's say we have the following directive:
@Directive({ selector: '[highlight]' })
export class HighlightDirective {
@HostBinding('style.background-color') backgroundColor : string;
@HostListener('mouseover')
onHover() {
this.backgroundColor = '#000000';
}
@HostListener('mouseout')
onLeave() {
this.backgroundColor = '#ffffff';
}
}
Let's see how we can test directives easily with Spectator:
describe('HighlightDirective', () => {
let spectator: SpectatorDirective<HighlightDirective>;
const createDirective = createDirectiveFactory(HighlightDirective);
beforeEach(() => {
spectator = createDirective(`<div highlight>Testing Highlight Directive</div>`);
});
it('should change the background color', () => {
spectator.dispatchMouseEvent(spectator.element, 'mouseover');
expect(spectator.element).toHaveStyle({
backgroundColor: 'rgba(0,0,0, 0.1)'
});
spectator.dispatchMouseEvent(spectator.element, 'mouseout');
expect(spectator.element).toHaveStyle({
backgroundColor: '#fff'
});
});
it('should get the instance', () => {
const instance = spectator.directive;
expect(instance).toBeDefined();
});
});
Testing Services
The following example shows how to test a service with Spectator:
import { createServiceFactory, SpectatorService } from '@ngneat/spectator';
import { AuthService } from 'auth.service.ts';
describe('AuthService', () => {
let spectator: SpectatorService<AuthService>;
const createService = createServiceFactory(AuthService);
beforeEach(() => spectator = createService());
it('should not be logged in', () => {
expect(spectator.service.isLoggedIn()).toBeFalsy();
});
});
The createService()
function returns SpectatorService
with the following properties:
-
service
- Get an instance of the service -
inject()
- A proxy for AngularTestBed.inject()
Additional Options
It's also possible to pass an object with options. For example, when testing a service you often want to mock its dependencies, as we focus on the service being tested.
For example:
@Injectable()
export class AuthService {
constructor( private dateService: DateService ) {}
isLoggedIn() {
if( this.dateService.isExpired('timestamp') ) {
return false;
}
return true;
}
}
In this case we can mock the DateService
dependency.
import { createServiceFactory } from '@ngneat/spectator';
import { AuthService } from 'auth.service.ts';
describe('AuthService', () => {
let spectator: SpectatorService<AuthService>;
const createService = createServiceFactory({
service: AuthService,
providers: [],
entryComponents: [],
mocks: [DateService]
});
beforeEach(() => spectator = createService());
it('should be logged in', () => {
const dateService = spectator.inject(DateService);
dateService.isExpired.and.returnValue(false);
expect(spectator.service.isLoggedIn()).toBeTruthy();
});
});
Testing Pipes
The following example shows how to test a pipe with Spectator:
import { SpectatorPipe, createPipeFactory } from '@ngneat/spectator';
import { StatsService } from './stats.service';
import { SumPipe } from './sum.pipe';
describe('SumPipe', () => {
let spectator: SpectatorPipe<SumPipe>;
const createPipe = createPipeFactory(SumPipe);
it('should sum up the given list of numbers (template)', () => {
spectator = createPipe(`{{ [1, 2, 3] | sum }}`);
expect(spectator.element).toHaveText('6');
});
it('should sum up the given list of numbers (prop)', () => {
spectator = createPipe(`{{ prop | sum }}`, {
hostProps: {
prop: [1, 2, 3]
}
});
expect(spectator.element).toHaveText('6');
});
it('should delegate the summation to the service', () => {
const sum = () => 42;
const provider = { provide: StatsService, useValue: { sum } };
spectator = createPipe(`{{ prop | sum }}`, {
hostProps: {
prop: [2, 40]
},
providers: [provider]
});
expect(spectator.element).toHaveText('42');
});
});
The createPipe()
function returns SpectatorPipe
with the following properties:
-
hostComponent
- Instance of the host component -
debugElement
- The debug element of the fixture around the host component -
element
- The native element of the host component -
detectChanges()
- A proxy for AngularTestBed.fixture.detectChanges()
-
inject()
- A proxy for AngularTestBed.inject()
Using Custom Host Component
The following example illustrates how to test a pipe using a custom host component:
import { Component, Input } from '@angular/core';
import { SpectatorPipe, createPipeFactory } from '@ngneat/spectator';
import { AveragePipe } from './average.pipe';
import { StatsService } from './stats.service';
@Component({
template: `<div>{{ prop | avg }}</div>`
})
class CustomHostComponent {
@Input() public prop: number[] = [1, 2, 3];
}
describe('AveragePipe', () => {
let spectator: SpectatorPipe<AveragePipe>;
const createPipe = createPipeFactory({
pipe: AveragePipe,
host: CustomHostComponent
});
it('should compute the average of a given list of numbers', () => {
spectator = createPipe();
expect(spectator.element).toHaveText('2');
});
it('should result to 0 when list of numbers is empty', () => {
spectator = createPipe({
hostProps: {
prop: []
}
});
expect(spectator.element).toHaveText('0');
});
it('should delegate the calculation to the service', () => {
const avg = () => 42;
const provider = { provide: StatsService, useValue: { avg } };
spectator = createPipe({
providers: [provider]
});
expect(spectator.element).toHaveText('42');
});
});
Mocking Providers
For every Spectator factory, we can easily mock any provider.
Every service that we pass to the mocks
property will be mocked using the mockProvider()
function.
The mockProvider()
function converts each method into a Jasmine spy. (i.e jasmine.createSpy()
).
Here are some of the methods it exposes:
dateService.isExpired.and.callThrough();
dateService.isExpired.and.callFake(() => fake);
dateService.isExpired.and.throwError('Error');
dateService.isExpired.andCallFake(() => fake);
However, if you use Jest as test framework and you want to utilize its mocking mechanism instead, import the mockProvider()
from @ngneat/spectator/jest
.
This will automatically use the jest.fn()
function to create a Jest compatible mock instead.
mockProvider()
doesn't include properties. In case you need to have properties on your mock you can use 2nd argument:
const createService = createServiceFactory({
service: AuthService,
providers: [
mockProvider(OtherService, {
name: 'Martin',
emitter: new Subject(),
mockedMethod: () => 'mocked'
})
],
});
Mocking OnInit dependencies
If a component relies on a service being mocked in the OnInit lifecycle method, change-detection needs to be disabled until after the services have been injected.
To configure this, change the createComponent
method to have the detectChanges
option set to false and then manually call detectChanges
on the spectator after setting up the injected services.
const createComponent = createComponentFactory({
component: WeatherDashboardComponent
});
it('should call the weather api on init', () => {
const spectator = createComponent({
detectChanges: false
});
const weatherService = spectator.inject(WeatherDataApi);
weatherService.getWeatherData.andReturn(of(mockWeatherData));
spectator.detectChanges();
expect(weatherService.getWeatherData).toHaveBeenCalled();
});
Mocking constructor dependencies
If a component relies on a service being mocked in its constructor, you need to create and configure the mock, and to provide the mock when creating the component.
const createComponent = createComponentFactory({
component: WeatherDashboardComponent
});
it('should call the weather api in the constructor', () => {
const weatherService = createSpyObject(WeatherDataApi);
weatherService.getWeatherData.andReturn(of(mockWeatherData));
spectator = createComponent({
providers: [
{ provide: WeatherDataApi, useValue: weatherService }
]
});
expect(weatherService.getWeatherData).toHaveBeenCalled();
});
Jest Support
By default, Spectator uses Jasmine for creating spies. If you are using Jest as test framework instead, you can let Spectator create Jest-compatible spies.
Just import one of the following functions from @ngneat/spectator/jest
(instead of @ngneat/spectator), and it will use Jest instead of Jasmine.
createComponentFactory()
, createHostFactory()
, createServiceFactory()
, createHttpFactory()
, mockProvider()
.
import { createServiceFactory, SpectatorService } from '@ngneat/spectator/jest';
import { AuthService } from './auth.service';
import { DateService } from './date.service';
describe('AuthService', () => {
let spectator: SpectatorService<AuthService>;
const createService = createServiceFactory({
service: AuthService,
mocks: [DateService]
});
beforeEach(() => spectator = createService());
it('should not be logged in', () => {
const dateService = spectator.inject<DateService>(DateService);
dateService.isExpired.mockReturnValue(true);
expect(spectator.service.isLoggedIn()).toBeFalsy();
});
it('should be logged in', () => {
const dateService = spectator.inject<DateService>(DateService);
dateService.isExpired.mockReturnValue(false);
expect(spectator.service.isLoggedIn()).toBeTruthy();
});
});
When using the component schematic you can specify the --jest
flag to have the Jest imports used. In order to Jest imports the default, update angular.json
:
"schematics": {
"@ngneat/spectator:spectator-component": {
"jest": true
}
}
Testing with HTTP
Spectator makes testing data services, which use the Angular HTTP module, a lot easier. For example, let's say that you have service with three methods, one performs a GET, one a POST and one performs concurrent requests:
export class TodosDataService {
constructor(private httpClient: HttpClient) {}
getTodos() {
return this.httpClient.get('api/todos');
}
postTodo(id: number) {
return this.httpClient.post('api/todos', { id });
}
collectTodos() {
return merge(
this.httpClient.get('/api1/todos'),
this.httpClient.get('/api2/todos')
);
}
}
The test for the above service should look like:
import { createHttpFactory, HttpMethod } from '@ngneat/spectator';
import { TodosDataService } from './todos-data.service';
describe('HttpClient testing', () => {
let spectator: SpectatorHttp<TodosDataService>;
const createHttp = createHttpFactory(TodosDataService);
beforeEach(() => spectator = createHttp());
it('can test HttpClient.get', () => {
spectator.service.getTodos().subscribe();
spectator.expectOne('api/todos', HttpMethod.GET);
});
it('can test HttpClient.post', () => {
spectator.service.postTodo(1).subscribe();
const req = spectator.expectOne('api/todos', HttpMethod.POST);
expect(req.request.body['id']).toEqual(1);
});
it('can test current http requests', () => {
spectator.service.getTodos().subscribe();
const reqs = spectator.expectConcurrent([
{ url: '/api1/todos', method: HttpMethod.GET },
{ URL: '/api2/todos', method: HttpMethod.GET }
]);
spectator.flushAll(reqs, [{}, {}, {}]);
});
});
We need to create an HTTP factory by using the createHttpFactory()
function, passing the service that you want to test. The createHttpFactory()
returns a function which can be called to get an instance of SpectatorHttp with the following properties:
-
controller
- A proxy for AngularHttpTestingController
-
httpClient
- A proxy for AngularHttpClient
-
service
- The service instance -
inject()
- A proxy for AngularTestBed.inject()
-
expectOne()
- Expect that a single request was made which matches the given URL and it's method, and return its mock request
Global Injections
It's possible to define injections which will be available for each test without the need to re-declare them in each test:
// test.ts
import { defineGlobalsInjections } from '@ngneat/spectator';
import { TranslocoModule } from '@ngneat/transloco';
defineGlobalsInjections({
imports: [TranslocoModule],
});
Please be aware, that defineGlobalsInjections()
must be called before the modules are loaded. In the default Angular test.ts
this means before this line:
context.keys().map(context);
Component Providers
By default, the original component providers (e.g. the providers
on the @Component
) are not touched.
However, in most cases, you want to access the component's providers in your test or replace them with mocks.
For example:
@Component({
template: '...',
providers: [FooService]
})
class FooComponent {
constructor(private fooService: FooService} {}
// ...
}
Use the componentProviders
to replace the FooService
provider:
const createComponent = createComponentFactory({
component: FooComponent,
componentProviders: [
{
provide: FooService,
useValue: someThingElse
}
]
})
Or mock the service by using componentMocks
:
const createComponent = createComponentFactory({
component: FooComponent,
componentMocks: [FooService]
});
To access the provider, get it from the component injector using the fromComponentInjector
parameter:
spectator.inject(FooService, true)
In the same way you can also override the component view providers by using the componentViewProviders
and componentViewProvidersMocks
.
The same rules also apply to directives using the directiveProviders
and directiveMocks
parameters.
Custom Matchers
expect('.zippy__content').not.toExist();
expect('.zippy__content').toHaveLength(3);
expect('.zippy__content').toHaveId('id');
expect(spectator.query('.zippy')).toHaveAttribute('id', 'zippy');
expect(spectator.query('.zippy')).toHaveAttribute({id: 'zippy'});
expect(spectator.query('.checkbox')).toHaveProperty('checked', true);
expect(spectator.query('.img')).toHaveProperty({src: 'assets/myimg.jpg'});
expect(spectator.query('.img')).toContainProperty({src: 'myimg.jpg'});
// Note that toHaveClass accepts classes only in strict order. If order is irrelevant, disable strict mode manually.
expect('.zippy__content').toHaveClass('class');
expect('.zippy__content').toHaveClass('class-a, class-b');
expect('.zippy__content').not.toHaveClass('class-b, class-a');
expect('.zippy__content').toHaveClass(['class-a', 'class-b']);
expect('.zippy__content').not.toHaveClass(['class-b', 'class-a']);
expect('.zippy__content').toHaveClass('class', { strict: false });
expect('.zippy__content').toHaveClass('class-a, class-b', { strict: false });
expect('.zippy__content').toHaveClass('class-b, class-a', { strict: false });
expect('.zippy__content').toHaveClass(['class-b', 'class-a'], { strict: false });
expect('.zippy__content').toHaveClass(['class-b', 'class-a'], { strict: false });
// Note that toHaveText only looks for the existence of a string, not if the string is exactly the same. If you want to verify that the string is completely the same, use toHaveExactText.
// Note that if you pass multiple values, Spectator checks the text of each array element against the index of the element found.
expect('.zippy__content').toHaveText('Content');
expect('.zippy__content').toHaveText(['Content A', 'Content B']);
expect('.zippy__content').toHaveText((text) => text.includes('..'));
expect('.zippy__content').toContainText('Content');
expect('.zippy__content').toContainText(['Content A', 'Content B']);
expect('.zippy__content').toHaveExactText('Content');
expect('.zippy__content').toHaveExactText(['Content A', 'Content B']);
expect('.zippy__content').toHaveValue('value');
expect('.zippy__content').toContainValue('value');
// Note this looks for multiple elements with the class and checks the value of each array element against the index of the element found
expect('.zippy__content').toHaveValue(['value a', 'value b']);
expect('.zippy__content').toContainValue(['value a', 'value b']);
expect(spectator.element).toHaveStyle({backgroundColor: 'rgba(0, 0, 0, 0.1)'});
expect('.zippy__content').toHaveData({data: 'role', val: 'admin'});
expect('.checkbox').toBeChecked();
expect('.checkbox').toBeIndeterminate();
expect('.button').toBeDisabled();
expect('div').toBeEmpty();
expect('div').toBeHidden();
expect('element').toBeSelected();
// Notice that due to restrictions within Jest (not applying actual layout logic in virtual DOM), certain matchers may result in false positives. For example width and height set to 0
expect('element').toBeVisible();
expect('input').toBeFocused();
expect('div').toBeMatchedBy('.js-something');
expect(spectator.component.object).toBePartial({ aProperty: 'aValue' });
expect('div').toHaveDescendant('.child');
expect('div').toHaveDescendantWithText({selector: '.child', text: 'text'});
Schematics
Generate component, service, and directive with Spectator spec templates with Angular Cli: (when using it as default)
Component
- Default spec:
ng g cs dashrized-name
- Spec with a host:
ng g cs dashrized-name --withHost=true
- Spec with a custom host:
ng g cs dashrized-name --withCustomHost=true
Service:
- Default spec:
ng g ss dashrized-name
- Spec for testing http data service:
ng g ss dashrized-name --isDataService=true
Directive:
ng g ds dashrized-name
Default Schematics Collection
To use spectator
as the default collection in your Angular CLI project,
add it to your angular.json
:
ng config cli.defaultCollection @ngneat/spectator
The spectator
schematics extend the default @schematics/angular
collection. If you want to set defaults for schematics such as generating components with scss file, you must change the schematics package name from @schematics/angular
to @ngneat/spectator
in angular.json
:
"schematics": {
"@ngneat/spectator:spectator-component": {
"style": "scss"
}
}
Working Spectator & Jest Sample Repo and Karma Comparison
The examples in Karma from Angular docs testing developer guide has been reproduced in Spectator and Jest. (For convenience, this is the local version of the Karma examples.)
The Spectator & Jest version can be accessed here.
Core Team
Netanel Basal |
Dirk Luijk |
Ben Elliott |
Contributors
Thanks goes to these wonderful people (emoji key):~~~~
This project follows the all-contributors specification. Contributions of any kind welcome!