Issue encountered while testing a component that incorporates a templateUrl

Question

Issue encountered while testing a component that incorporates a templateUrl

Upon reviewing the test output, it appears that

console.log(dummyComponentInstance);

is being invoked and resulting in undefined.

In addition, the log for console.log('beforeEach done'); is never displayed.

The code within dummy.component.spec.ts:

import { async, ComponentFixture, TestBed } from '@angular/core/testing';

import { DummyComponent } from './dummy.component';

describe('DummyComponent', () => {

  let dummyComponentInstance: DummyComponent;
  let fixture: ComponentFixture<DummyComponent>;

  beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [DummyComponent]
    })
      .compileComponents()
      .then(() => {
        fixture = TestBed.createComponent(DummyComponent);
        dummyComponentInstance = fixture.componentInstance;
        console.log('beforeEach done');
      });
  }));

  it('should work', () => {
    console.log(dummyComponentInstance);
    expect(dummyComponentInstance instanceof DummyComponent).toBe(true, 'should create DummyComponent');
  });
});

The content of dummy.component.ts:

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

@Component({
  selector: 'dummy',
  templateUrl: './dummy.component.html'
})
export class DummyComponent {
  public initialized = false;
}

Error message after running the test:

07 06 2017 13:27:09.187:INFO [launcher]: Starting browser PhantomJS
07 06 2017 13:27:09.437:INFO [PhantomJS 2.1.1 (Linux 0.0.0)]: Connected on socket 4Vq49vX24cDAIZfjAAAA with id 34827962
LOG: undefined
PhantomJS 2.1.1 (Linux 0.0.0) DummyComponent should work FAILED
    invokeTask@/tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:605:36
    onInvokeTask@/tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:154:49
    invokeTask@/tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:604:48
    runTask@/tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:372:57
    drainMicroTaskQueue@/tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:765:42
    run@/tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:17951:29
    /tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:17964:31
    flush@/tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:17813:11
    resolvePromise@/tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:951:78
    resolvePromise@/tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:921:31
    /tmp/karma-typescript-bundle-27168S216WqzJyZ6g.js:998:31
    Expected false to be true, 'should create DummyComponent'.
    src/app/dummy.component.spec.js:21:98

angular unit-testing typescript

Answer 1

Answer №1

Would you be open to giving this a try?

Try bringing in fakeAsync and tick from @angular/core/testing. Reframe the code by moving the content within .then() into the test case, utilizing fakeAsync() there. I'd love to hear about your experience with it.

beforeEach(async(() => {
    TestBed.configureTestingModule({
        declarations: [DummyComponent]
    })
    .compileComponents();
}));

it('should perform correctly', fakeAsync(() => {
    fixture = TestBed.createComponent(DummyComponent);
    dummyComponentInstance = fixture.componentInstance;
    tick();

    expect(dummyComponentInstance instanceof DummyComponent).toBe(true, 'should instantiate DummyComponent');
}));

Give it a go and let me know how it goes!

Answer 2

Would you be open to giving this a try?

Try bringing in fakeAsync and tick from @angular/core/testing. Reframe the code by moving the content within .then() into the test case, utilizing fakeAsync() there. I'd love to hear about your experience with it.

beforeEach(async(() => {
    TestBed.configureTestingModule({
        declarations: [DummyComponent]
    })
    .compileComponents();
}));

it('should perform correctly', fakeAsync(() => {
    fixture = TestBed.createComponent(DummyComponent);
    dummyComponentInstance = fixture.componentInstance;
    tick();

    expect(dummyComponentInstance instanceof DummyComponent).toBe(true, 'should instantiate DummyComponent');
}));

Give it a go and let me know how it goes!

Answer 3

Answer №2

My templateUrl file includes an Angular form that required setup in my TestBed object:

beforeEach(async(() => {
  TestBed.configureTestingModule({
    declarations: [PageFormComponent],
    imports: [FormsModule]
  }).compileComponents()
    .then(() => {
      fixture = TestBed.createComponent(PageFormComponent);
      pageFormComponentInstance = fixture.componentInstance;
    });
}));

Answer 4

My templateUrl file includes an Angular form that required setup in my TestBed object:

beforeEach(async(() => {
  TestBed.configureTestingModule({
    declarations: [PageFormComponent],
    imports: [FormsModule]
  }).compileComponents()
    .then(() => {
      fixture = TestBed.createComponent(PageFormComponent);
      pageFormComponentInstance = fixture.componentInstance;
    });
}));

Answer 5

Answer №3

There are a couple of things that I'm a bit confused about. Does the dummy.component.html file actually exist?

When you run the following code:

beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [DummyComponent]
    })
      .compileComponents()
      .then(() => {
        fixture = TestBed.createComponent(DummyComponent);
        dummyComponentInstance = fixture.componentInstance;
        console.log('beforeEach done');
      });
  }));

Essentially, you're telling Angular to fetch some files asynchronously and then compile the template to create the fixture.

If the HTML file doesn't exist, your testbed configuration will fail. Have you created the dummy.component.html file? You didn't include it in your example.

I tested your code in my project with both an empty template and an empty templateUrl file, and it worked fine in both cases.

If you don't have the HTML file yet or if you're not testing it, consider skipping the expensive operation of creating the fixture altogether. It's resource-intensive and may not be necessary for your tests.

If you do have a dummy.component.html file with elements that the dynamic module can't interpret, you can import NO_SCHEMA_ERRORS from @angular/core and add it to your TestBed configuration:

...
schemas: [NO_SCHEMA_ERRORS]
...

Alternatively, teach the testbed how to handle those elements by importing the necessary parts. But in this case, it seems like the issue is simply that the dummy.component.html file is missing.

I hope this explanation helps clarify things for you.

Answer 6

There are a couple of things that I'm a bit confused about. Does the dummy.component.html file actually exist?

When you run the following code:

beforeEach(async(() => {
    TestBed.configureTestingModule({
      declarations: [DummyComponent]
    })
      .compileComponents()
      .then(() => {
        fixture = TestBed.createComponent(DummyComponent);
        dummyComponentInstance = fixture.componentInstance;
        console.log('beforeEach done');
      });
  }));

Essentially, you're telling Angular to fetch some files asynchronously and then compile the template to create the fixture.

If the HTML file doesn't exist, your testbed configuration will fail. Have you created the dummy.component.html file? You didn't include it in your example.

I tested your code in my project with both an empty template and an empty templateUrl file, and it worked fine in both cases.

If you don't have the HTML file yet or if you're not testing it, consider skipping the expensive operation of creating the fixture altogether. It's resource-intensive and may not be necessary for your tests.

If you do have a dummy.component.html file with elements that the dynamic module can't interpret, you can import NO_SCHEMA_ERRORS from @angular/core and add it to your TestBed configuration:

...
schemas: [NO_SCHEMA_ERRORS]
...

Alternatively, teach the testbed how to handle those elements by importing the necessary parts. But in this case, it seems like the issue is simply that the dummy.component.html file is missing.

I hope this explanation helps clarify things for you.

Issue encountered while testing a component that incorporates a templateUrl

Answer №1

Answer №2

Answer №3

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