Add tests for sticky-header

src/lib/sticky-header/index.ts

@@ -8,14 +8,18 @@
 import {NgModule} from '@angular/core';
 import {CommonModule} from '@angular/common';
 import {OverlayModule, MdCommonModule, PlatformModule} from '../core';
-import {CdkStickyRegion, CdkStickyHeader} from './sticky-header';
-
+import {
+  CdkStickyRegion,
+  CdkStickyHeader,
+  STICKY_HEADER_SUPPORT_STRATEGY_PROVIDER
+} from './sticky-header';
 
 
 @NgModule({
   imports: [OverlayModule, MdCommonModule, CommonModule, PlatformModule],
   declarations: [CdkStickyRegion, CdkStickyHeader],
   exports: [CdkStickyRegion, CdkStickyHeader, MdCommonModule],
+  providers: [STICKY_HEADER_SUPPORT_STRATEGY_PROVIDER]
 })
 export class StickyHeaderModule {}
 

src/lib/sticky-header/sticky-header.spec.ts

@@ -0,0 +1,180 @@
+import {async, ComponentFixture, TestBed, fakeAsync, tick} from '@angular/core/testing';
+import {Component, DebugElement, ViewChild} from '@angular/core';
+import {
+  StickyHeaderModule,
+  CdkStickyRegion,
+  CdkStickyHeader,
+  STICKY_HEADER_SUPPORT_STRATEGY
+} from './index';
+import {OverlayModule, Scrollable} from '../core/overlay/index';
+import {PlatformModule} from '../core/platform/index';
+import {By} from '@angular/platform-browser';
+import {dispatchFakeEvent} from '@angular/cdk/testing';
+
+
+
+describe('sticky-header with positioning not supported', () => {
+  let fixture: ComponentFixture<StickyHeaderTest>;
+  let testComponent: StickyHeaderTest;
+  let stickyElement: DebugElement;
+  let stickyParentElement: DebugElement;
+  let scrollableElement: DebugElement;
+  let stickyHeader: CdkStickyHeader;
+
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      imports: [ OverlayModule, PlatformModule, StickyHeaderModule ],
+      declarations: [StickyHeaderTest],
+      providers: [
+        {provide: STICKY_HEADER_SUPPORT_STRATEGY, useValue: false},
+      ],
+    });
+    TestBed.compileComponents();
+  }));
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(StickyHeaderTest);
+    fixture.detectChanges();
+    testComponent = fixture.debugElement.componentInstance;
+    stickyElement = fixture.debugElement.query(By.directive(CdkStickyHeader));
+    stickyParentElement = fixture.debugElement.query(By.directive(CdkStickyRegion));
+    stickyHeader = stickyElement.injector.get<CdkStickyHeader>(CdkStickyHeader);
+    scrollableElement = fixture.debugElement.query(By.directive(Scrollable));
+  });
+
+  it('should be able to find stickyParent', () => {
+    expect(stickyHeader.stickyParent).not.toBe(null);
+  });
+
+  it('should be able to find scrollableContainer', () => {
+    expect(stickyHeader.upperScrollableContainer).not.toBe(null);
+  });
+
+  it('should stick in the right place when scrolled to the top of the container', fakeAsync(() => {
+    let scrollableContainerTop = stickyHeader.upperScrollableContainer
+      .getBoundingClientRect().top;
+    expect(stickyHeader.element.getBoundingClientRect().top).not.toBe(scrollableContainerTop);
+    tick();
+
+    // Scroll the scrollableContainer up to stick
+    fixture.componentInstance.scrollDown();
+    // wait till animation has finished
+    tick(100);
+
+    expect(stickyHeader.element.getBoundingClientRect().top).toBe(scrollableContainerTop);
+  }));
+
+  it('should unstuck when scrolled off the top of the container', fakeAsync(() => {
+    let scrollableContainerTop = stickyHeader.upperScrollableContainer
+      .getBoundingClientRect().top;
+    expect(stickyHeader.element.getBoundingClientRect().top).not.toBe(scrollableContainerTop);
+    tick();
+
+    // Scroll the scrollableContainer up to stick
+    fixture.componentInstance.scrollDown();
+    // wait till animation has finished
+    tick(100);
+
+    expect(stickyHeader.element.getBoundingClientRect().top).toBe(scrollableContainerTop);
+
+    // Scroll the scrollableContainer down to unstuck
+    fixture.componentInstance.scrollBack();
+    tick(100);
+
+    expect(stickyHeader.element.getBoundingClientRect().top).not.toBe(scrollableContainerTop);
+
+  }));
+});
+
+describe('sticky-header with positioning supported', () => {
+  let fixture: ComponentFixture<StickyHeaderTest>;
+  let testComponent: StickyHeaderTest;
+  let stickyElement: DebugElement;
+  let stickyParentElement: DebugElement;
+  let stickyHeader: CdkStickyHeader;
+
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      imports: [ OverlayModule, PlatformModule, StickyHeaderModule ],
+      declarations: [StickyHeaderTest],
+      providers: [
+        {provide: STICKY_HEADER_SUPPORT_STRATEGY, useValue: true},
+      ],
+    });
+    TestBed.compileComponents();
+  }));
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(StickyHeaderTest);
+    fixture.detectChanges();
+    testComponent = fixture.debugElement.componentInstance;
+    stickyElement = fixture.debugElement.query(By.directive(CdkStickyHeader));
+    stickyParentElement = fixture.debugElement.query(By.directive(CdkStickyRegion));
+    stickyHeader = stickyElement.injector.get<CdkStickyHeader>(CdkStickyHeader);
+  });
+
+  it('should find sticky positioning is applied', () => {
+    let position = window.getComputedStyle(stickyHeader.element).position;
+    expect(position).not.toBe(null);
+    expect(/sticky/i.test(position!)).toBe(true);
+  });
+});
+
+@Component({
+  // Use styles to define the style of scrollable container and header,
+  // which help test to make sure whether the header is stuck at the right position.
+  styles:[`
+    .scrollable-style {
+      text-align: center;
+      -webkit-appearance: none;
+      -moz-appearance: none;
+      height: 300px;
+      overflow: auto;
+    }
+    .heading-style {
+      background: whitesmoke;
+      padding: 5px;
+    }
+  `],
+  template: `
+    <div cdk-scrollable class="scrollable-style">
+      <p *ngFor="let item of items"> {{item.name}} : {{item.message}}</p>
+      <div cdkStickyRegion>
+        <div cdkStickyHeader class="heading-style">
+          <h2>Heading 1</h2>
+        </div>
+        <p *ngFor="let item of items"> {{item.name}} : {{item.message}}</p>
+        <p *ngFor="let item of items"> {{item.name}} : {{item.message}}</p>
+        <p *ngFor="let item of items"> {{item.name}} : {{item.message}}</p>
+      </div>
+    </div>
+  `})
+class StickyHeaderTest {
+  @ViewChild(Scrollable) scrollingContainer: Scrollable;
+
+  items: any[] = [
+    {'name': 'Forrest', 'message': 'Life was like a box of chocolates'},
+    {'name': 'Gump', 'message': 'you never know what you are gonna get'},
+    {'name': 'Lion King', 'message': 'Everything you see exists together'},
+    {'name': 'Jack', 'message': 'in a delicate balance'},
+    {'name': 'Garfield', 'message': 'Save Water'},
+    {'name': 'Shawshank', 'message': 'There is something inside'},
+    {'name': 'Jone', 'message': 'Enough movies?'},
+  ];
+
+  scrollDown() {
+    const scrollingContainerEl = this.scrollingContainer.getElementRef().nativeElement;
+    scrollingContainerEl.scrollTop = 300;
+
+    // Emit a scroll event from the scrolling element in our component.
+    dispatchFakeEvent(scrollingContainerEl, 'scroll');
+  }
+
+  scrollBack() {
+    const scrollingContainerEl = this.scrollingContainer.getElementRef().nativeElement;
+    scrollingContainerEl.scrollTop = 0;
+
+    // Emit a scroll event from the scrolling element in our component.
+    dispatchFakeEvent(scrollingContainerEl, 'scroll');
+  }
+}

src/lib/sticky-header/sticky-header.ts

@@ -6,8 +6,9 @@
  * found in the LICENSE file at https://angular.io/license
  */
 import {Directive, Input,
-  OnDestroy, AfterViewInit, ElementRef, Optional} from '@angular/core';
-import {Platform} from '../core/platform';
+  OnDestroy, AfterViewInit, ElementRef, Optional,
+  InjectionToken, Injectable, Inject, Provider} from '@angular/core';
+import {Platform} from '../core/platform/index';
 import {Scrollable} from '../core/overlay/scroll/scrollable';
 import {extendObject} from '../core/util/object-extend';
 import {Subscription} from 'rxjs/Subscription';
@@ -32,7 +33,6 @@ export class CdkStickyRegion {
   constructor(public readonly _elementRef: ElementRef) { }
 }
 
-
 /** Class applied when the header is "stuck" */
 const STICK_START_CLASS = 'cdk-sticky-header-start';
 
@@ -46,6 +46,16 @@ const STICK_END_CLASS = 'cdk-sticky-header-end';
  */
 const DEBOUNCE_TIME: number = 5;
 
+export const STICKY_HEADER_SUPPORT_STRATEGY = new InjectionToken('sticky-header-support-strategy');
+
+/** @docs-private
+ * Create a factory for sticky-positioning check to make code more testable
+ */
+export const STICKY_HEADER_SUPPORT_STRATEGY_PROVIDER: Provider = {
+  provide: STICKY_HEADER_SUPPORT_STRATEGY,
+  useFactory: isPositionStickySupported
+};
+
 /**
  * Directive that marks an element as a sticky-header. Inside of a scrolling container (marked with
  * cdkScrollable), this header will "stick" to the top of the scrolling viewport while its sticky
@@ -61,8 +71,6 @@ export class CdkStickyHeader implements OnDestroy, AfterViewInit {
 
   /** boolean value to mark whether the current header is stuck*/
   isStuck: boolean = false;
-  /** Whether the browser support CSS sticky positioning. */
-  private _isPositionStickySupported: boolean = false;
 
   /** The element with the 'cdkStickyHeader' tag. */
   element: HTMLElement;
@@ -97,7 +105,8 @@ export class CdkStickyHeader implements OnDestroy, AfterViewInit {
   constructor(element: ElementRef,
               scrollable: Scrollable,
               @Optional() public parentRegion: CdkStickyRegion,
-              platform: Platform) {
+              platform: Platform,
+              @Inject(STICKY_HEADER_SUPPORT_STRATEGY) public _isPositionStickySupported) {
     if (platform.isBrowser) {
       this.element = element.nativeElement;
       this.upperScrollableContainer = scrollable.getElementRef().nativeElement;
@@ -137,7 +146,6 @@ export class CdkStickyHeader implements OnDestroy, AfterViewInit {
    * sticky positioning. If not, use the original implementation.
    */
   private _setStrategyAccordingToCompatibility(): void {
-    this._isPositionStickySupported = isPositionStickySupported();
     if (this._isPositionStickySupported) {
       this.element.style.top = '0';
       this.element.style.cssText += 'position: -webkit-sticky; position: sticky; ';
@@ -258,9 +266,9 @@ export class CdkStickyHeader implements OnDestroy, AfterViewInit {
 
 
   /**
-   * '_applyStickyPositionStyles()' function contains the main logic of sticky-header. It decides when
-   * a header should be stick and when should it be unstuck by comparing the offsetTop
-   * of scrollable container with the top and bottom of the sticky region.
+   * '_applyStickyPositionStyles()' function contains the main logic of sticky-header.
+   * It decides when a header should be stick and when should it be unstuck by comparing
+   * the offsetTop of scrollable container with the top and bottom of the sticky region.
    */
   _applyStickyPositionStyles(): void {
     let currentPosition: number = this.upperScrollableContainer.offsetTop;