Directive TestBed

Custom test bed for testing Directive.

info

Works for standalone and non-standalone directive.

Quick example

@Component({
  template: `<span id="my-text" [highlight]="color">My Text</span>`,
  standalone: true,
  imports: [AppDirective],
})
class HostComponent {
  public color: string | undefined;
}

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent);

  it('should ', tb(({ host, fixture, directive, query }) => {
    const span = query.findElement<HTMLSpanElement>('#my-text');

    expect(span.style.backgroundColor).toEqual(directive.DEFAULT_COLOR);

    host.color = 'red';
    fixture.detectChanges();

    expect(span.style.backgroundColor).toEqual('red');
  }));
});

directiveTestBed(..)

Creates a specific test bed for directive.

It returns a function to be used to wrap it's callback and from which you access tools (check DirectiveTools).

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent);

  it('should ', tb((tools) => { // 👈 tb function used here
    // ... expectations
  }));
});

tb function supports the jasmine DoneFn and async/await notation.

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent);

  it('should ', tb(async (tools) => {
    // ... async expectations
  }));

  it('should ', tb((tools, done) => {
    // ... expectations
    done();
  }));
});

TestBed Options

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent, {} /* 👈 here */);

  it('should ', tb(() => {
    // ... expectations
  }));
});

imports

Default : []

Imports template's dependencies for the described host component and its children.

remarque

It is often used for non-standalone component, because standalone component embed its own importations.

Example :

const tb = directiveTestBed(AppDirective, HostComponent, {
  imports: [SharedModule, MaterialModule],
});

providers

Default : []

List of providers to be available during tests for the described host component and its children.

Example :

const tb = directiveTestBed(AppDirective, HostComponent, {
  providers: [AppService, { provide: StoreService, useClass: MockStoreService }],
});

declarations

Default : []

List of components, directives and pipes to be used in the described non-standalone host component template.

Example :

const tb = directiveTestBed(AppDirective, HostComponent, {
  declarations: [ChildComponent, ColorDirective, AppPipe],
});

schemas

Default : []

Allows specific elements and properties to be used in the template.

See Angular CUSTOM_ELEMENTS_SCHEMA and NO_ERRORS_SCHEMA.

Example :

const tb = directiveTestBed(AppDirective, HostComponent, {
  schemas: [CUSTOM_ELEMENTS_SCHEMA],
});

noopAnimations

Default : true

Disable Angular animation.

remarque

It provides provideNoopAnimation() under the hood.

startDetectChanges

Default : true

Runs host component fixture.detectChanges() before each assertion.

attention

Has no effect if noTemplate is true.

noTemplate

Default : false

Useful when you only want to test the logic of the described host component.

If enabled, no template will be rendered and no change detections will be performed.

autoCompile

Default : true

Automatically compiles the custom test bed for each test.

checkCreate

Default : true

Automatically invokes the "should create" Angular test.

It checks if the provided described instance is truthy.

Assertion tools

The tb function provides DirectiveTools.

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent);

  it('should ', tb((tools /* 👈 here */) => {
    // ... expectations
  }));
});

👉 DirectiveTools extends BaseTools and RendererTools.

directive

The described directive instance.

info

The instance is typed according to the passed component Type<T> in directiveTestBed(..).

Example :

it('should ', tb(({ directive }) => {
  expect(directive.prop).toEqual('foo');
}));

host

The host component.

it('should ', tb(({ host }) => {
  // ... expectations
}));

Assertion options

For specific test, you enable/disable options that override the test bed options.

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent);

  it('should ', tb((tools) => {
    // ... expectations
  }, {} /* 👈 here */));
});

startDetectChanges

Same as options startDetectChanges but only for the current assertion.

ComponentTestBed

import(..)

Same as options imports but with chaining methods.

Example :

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent)
    .import(SharedModule)
    .import([ThirdPartyModule, MaterialModule]);
});

provide(..)

Same as options providers but with chaining methods.

Example :

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent)
    .provide(AppService)
    .provide([StoreService, { provide: MY_TOKEN, useValue: mockValue }]);
});

declare(..)

Same as options declarations but with chaining methods.

Example :

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent)
    .declare(ChildComponent)
    .declare([HeaderComponent, AppPipe]);
});

inject(..)

Links an injected instance to a key and retrieve it into the enhanced tools by autocompletion.

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent)
    .inject('auth', AuthService);

  it('should ', tb(({ injected: { auth } }) => {
    // ... expectations
  }));
});

setup(..)

Setups extra action using the enhanced tools.

Works only for beforeEach and afterEach.

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent);

  beforeEach(tb.setup(({ directive }) => {
    directive.foo = true;
  }));
});

compile()

To be used when you need to do third party setups before compiling the custom test bed.

attention

It has to be used into beforeEach(..) and autoCompile must be set to false.

describe('AppDirective', () => {
  const tb = directiveTestBed(AppDirective, HostComponent, { autoCompile: false });

  beforeEach(async () => {
    // ... third party setup
    await tb.compile();
  });
});

itShouldCreateDirective(..)

Create the "should create" for the described directive.

To be used when there are no noticeable or relevant tests to be performed.

describe('AppDirective', () => {
  itShouldCreateComponent(AppDirective);
});