weird-jasmine-test.ts

/**
 * 
 * Run the following code with `ng test` 
 * Is this a jasmine, typescript, angular or stupid developer bug?
 **/

import {
  ComponentFactory,
  ComponentRef,
  ElementRef,
  EmbeddedViewRef,
  Injector,
  TemplateRef,
  ViewContainerRef,
  ViewRef
} from '@angular/core';

export class ViewContainerRefMock1 extends ViewContainerRef {
  clear(): void {
  }

  get(index: number): ViewRef {
    return undefined;
  }

  createEmbeddedView<C>(templateRef: TemplateRef<C>, context?: C, index?: number): EmbeddedViewRef<C> {
    return undefined;
  }

  createComponent<C>(componentFactory: ComponentFactory<C>, index?: number, injector?: Injector, projectableNodes?: any[][]): ComponentRef<C> {
    return undefined;
  }

  insert(viewRef: ViewRef, index?: number): ViewRef {
    return undefined;
  }

  move(viewRef: ViewRef, currentIndex: number): ViewRef {
    return undefined;
  }

  indexOf(viewRef: ViewRef): number {
    return undefined;
  }

  remove(index?: number): void {
  }

  detach(index?: number): ViewRef {
    return undefined;
  }

  constructor() {
    super();
  }

  _element: ElementRef = {
    nativeElement: {
      scrollTop: 0
    }
  };

  get element(): ElementRef {
    return this._element;
  }
}

export class ViewContainerRefMock2 extends ViewContainerRef {
  clear(): void {
  }

  get(index: number): ViewRef {
    return undefined;
  }

  createEmbeddedView<C>(templateRef: TemplateRef<C>, context?: C, index?: number): EmbeddedViewRef<C> {
    return undefined;
  }

  createComponent<C>(componentFactory: ComponentFactory<C>, index?: number, injector?: Injector, projectableNodes?: any[][]): ComponentRef<C> {
    return undefined;
  }

  insert(viewRef: ViewRef, index?: number): ViewRef {
    return undefined;
  }

  move(viewRef: ViewRef, currentIndex: number): ViewRef {
    return undefined;
  }

  indexOf(viewRef: ViewRef): number {
    return undefined;
  }

  remove(index?: number): void {
  }

  detach(index?: number): ViewRef {
    return undefined;
  }

  constructor() {
    super();
  }

  public element: ElementRef = {
    nativeElement: {
      scrollTop: 0
    }
  };
}

export const scrollTop = (viewRef: ViewContainerRef, scrollTop: number) => {
  viewRef.element.nativeElement.scrollTop = scrollTop;
};

fdescribe('Function: scrollTop - working', () => {
  let viewRef: ViewContainerRef;

  beforeEach(() => {
    viewRef = new ViewContainerRefMock1();
  });

  it('should set viewRef.element.nativeElement.scrollTop', () => {
    scrollTop(viewRef, 23);
    expect(viewRef.element.nativeElement.scrollTop).toBe(23);
  });
});

fdescribe('Function: scrollTop - not working', () => {
  let viewRef: ViewContainerRef;

  beforeEach(() => {
    viewRef = new ViewContainerRefMock2();
  });

  it('should set viewRef.element.nativeElement.scrollTop', () => {
    scrollTop(viewRef, 23);
    expect(viewRef.element.nativeElement.scrollTop).toBe(23);
  });
});