Unit test error: Cannot call Promise.then from within a sync test

Move your variable initialization inside a beforeEach.

You shouldn't be getting things out of the TestBed or managing the fixture or component in the describe scope. You should only do these things within the scope of a test run: inside a beforeEach/beforeAll, afterEach/afterAll, or inside an it.

describe(("test input "), () => {  let comp: ToDoComponent;  let fixture: ComponentFixture<ToDoComponent>;  let de: DebugElement;  let el: HTMLElement;  beforeEach(async(() => {    TestBed.configureTestingModule({        declarations: [ToDoComponent],        imports: [FormsModule]      })      .compileComponents();  }));  beforeEach(() => {    fixture = TestBed.createComponent(ToDoComponent);    comp = fixture.componentInstance;    de = fixture.debugElement.query(By.css("h1"));    el = de.nativeElement;  })  it('should display a different test title', () => {    comp.pageTitle = 'Test Title';    fixture.detectChanges();    expect(el.textContent).toBe('Test Title423');  });});

See also

• https://angular.io/docs/ts/latest/guide/testing.html#!#waiting-compile-components

I got the same error for a different reason. I put a TestBed.get(Dependency) call within a describe block. The fix was moving it to the it block.

Wrong:

describe('someFunction', () => {    const dependency = TestBed.get(Dependency); // this was causing the error    it('should not fail', () => {        someFunction(dependency);    });});

Fixed:

describe('someFunction', () => {    it('should not fail', () => {        const dependency = TestBed.get(Dependency); // putting it here fixed the issue        someFunction(dependency);    });});