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How to test a multi token in Angular application

If you did not read "How to test a token", please do it first.

Testing multi tokens is quite similar with the difference that TestBet.get returns an array of all providers matching the token.

const values = TestBed.get(TOKEN_MULTI);
expect(values).toEqual(jasmine.any(Array));
expect(values.length).toEqual(4);

Live example‚Äč

https://github.com/help-me-mom/ng-mocks/blob/master/examples/TestMultiToken/test.spec.ts
import { Injectable, InjectionToken, NgModule } from '@angular/core';

import { MockBuilder, MockRender } from 'ng-mocks';

const TOKEN_MULTI = new InjectionToken('MULTI');

class ServiceClass {
public readonly name = 'class';
}

@Injectable()
class ServiceExisting {
public readonly name = 'existing';
}

// A module that provides all services.
@NgModule({
providers: [
ServiceExisting,
{
multi: true,
provide: TOKEN_MULTI,
useClass: ServiceClass,
},
{
multi: true,
provide: TOKEN_MULTI,
useExisting: ServiceExisting,
},
{
multi: true,
provide: TOKEN_MULTI,
useFactory: () => 'FACTORY',
},
{
multi: true,
provide: TOKEN_MULTI,
useValue: 'VALUE',
},
],
})
class TargetModule {}

describe('TestMultiToken', () => {
// Because we want to test the token, we pass it as the first
// parameter of MockBuilder. To correctly satisfy its initialization
// we need to pass its module as the second parameter.
// Do not forget to return the promise of MockBuilder.
beforeEach(() => MockBuilder(TOKEN_MULTI, TargetModule));

it('creates TOKEN_MULTI', () => {
const tokens =
MockRender<any[]>(TOKEN_MULTI).point.componentInstance;

expect(tokens).toEqual(jasmine.any(Array));
expect(tokens.length).toEqual(4);

// Verifying that the token is an instance of ServiceClass.
expect(tokens[0]).toEqual(jasmine.any(ServiceClass));
expect(tokens[0].name).toEqual('class');

// Verifying that the token is an instance of ServiceExisting.
// But because it has been replaced with its mock copy
// we should see an empty name.
expect(tokens[1]).toEqual(jasmine.any(ServiceExisting));
expect(tokens[1].name).toBeUndefined();

// Checking that we have here what factory has been created.
expect(tokens[2]).toEqual('FACTORY');

// Checking the set value.
expect(tokens[3]).toEqual('VALUE');
});
});