Is there a way to simulate the @Attribute decorator string provider in an ng2 unit test?

Struggling with unit testing a component and facing a hurdle. Unsure how to mock the functionality of the @Attribute decorator in my test.

Error: No provider for String!

@Component({...})
export class MyComponent {
    constructor(@Attribute("handle") private handle: string) { }
}

Need guidance on what to 'provide' in my test.

{ provide: ??, useValue: "" }

UPDATE

Test setup below:

describe("MyComponent", () => {
    let component: MyComponent;

    beforeEach(() => {
        this.injector = ReflectiveInjector.resolveAndCreate([
            { provide: ??, useValue: "" }, //@Attribute provider??
            ... // other mocked providers
            MyComponent
        ]);

        component = this.injector.get(MyComponent);
    });
    ...
});

Answer №1

This code snippet should be helpful for your situation

{ provide: String, useValue: "test" },
AppComponent

Alternatively, the following approach can also be used:

import { Inject} from '@angular/core';

let token = 'handle';
Inject(token)(MyComponent, null, 0); // 0 represents the index of your parameter

let injector = ReflectiveInjector.resolveAndCreate([
  { provide: token, useValue: "test" },

In case you have multiple parameters of type string like this:

export class MyComponent {
  constructor(
    @Attribute("handle") private handle: string, 
    @Attribute("handle2") private handle2: string) {}

You can do the following:

Inject('handle')(MyComponent, null, 0);
Inject('handle2')(MyComponent, null, 1);

let injector = ReflectiveInjector.resolveAndCreate([
  { provide: 'handle', useValue: "test" },
  { provide: 'handle2', useValue: "test2" },

Check out this Plunker Example for reference

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