docs(material/tree): add harness example for tree

src/components-examples/material/tree/BUILD.bazel

@@ -11,12 +11,18 @@ ng_module(
     ]),
     module_name = "@angular/components-examples/material/tree",
     deps = [
+        "//src/cdk/testing",
+        "//src/cdk/testing/testbed",
         "//src/material/button",
         "//src/material/checkbox",
         "//src/material/icon",
         "//src/material/input",
         "//src/material/progress-bar",
         "//src/material/tree",
+        "//src/material/tree/testing",
+        "@npm//@angular/platform-browser",
+        "@npm//@angular/platform-browser-dynamic",
+        "@npm//@types/jasmine",
     ],
 )
 

src/components-examples/material/tree/index.ts

@@ -9,13 +9,15 @@ import {MatTreeModule} from '@angular/material/tree';
 import {TreeChecklistExample} from './tree-checklist/tree-checklist-example';
 import {TreeDynamicExample} from './tree-dynamic/tree-dynamic-example';
 import {TreeFlatOverviewExample} from './tree-flat-overview/tree-flat-overview-example';
+import {TreeHarnessExample} from './tree-harness/tree-harness-example';
 import {TreeLoadmoreExample} from './tree-loadmore/tree-loadmore-example';
 import {TreeNestedOverviewExample} from './tree-nested-overview/tree-nested-overview-example';
 
 export {
   TreeChecklistExample,
   TreeDynamicExample,
   TreeFlatOverviewExample,
+  TreeHarnessExample,
   TreeLoadmoreExample,
   TreeNestedOverviewExample,
 };
@@ -24,6 +26,7 @@ const EXAMPLES = [
   TreeChecklistExample,
   TreeDynamicExample,
   TreeFlatOverviewExample,
+  TreeHarnessExample,
   TreeLoadmoreExample,
   TreeNestedOverviewExample,
 ];

src/components-examples/material/tree/tree-harness/tree-harness-example.html

@@ -0,0 +1,18 @@
+<mat-tree [dataSource]="dataSource" [treeControl]="treeControl">
+  <!-- This is the tree node template for leaf nodes -->
+  <mat-tree-node *matTreeNodeDef="let node" matTreeNodePadding>
+    <!-- use a disabled button to provide padding for tree leaf -->
+    <button mat-icon-button disabled></button>
+    {{node.name}}
+  </mat-tree-node>
+  <!-- This is the tree node template for expandable nodes -->
+  <mat-tree-node *matTreeNodeDef="let node;when: hasChild" matTreeNodePadding>
+    <button mat-icon-button matTreeNodeToggle
+            [attr.aria-label]="'Toggle ' + node.name">
+      <mat-icon class="mat-icon-rtl-mirror">
+        {{treeControl.isExpanded(node) ? 'expand_more' : 'chevron_right'}}
+      </mat-icon>
+    </button>
+    {{node.name}}
+  </mat-tree-node>
+</mat-tree>

src/components-examples/material/tree/tree-harness/tree-harness-example.spec.ts

@@ -0,0 +1,82 @@
+import {TestBed, ComponentFixture, waitForAsync} from '@angular/core/testing';
+import {TestbedHarnessEnvironment} from '@angular/cdk/testing/testbed';
+import {MatTreeHarness} from '@angular/material/tree/testing';
+import {HarnessLoader} from '@angular/cdk/testing';
+import {BrowserDynamicTestingModule, platformBrowserDynamicTesting}
+  from '@angular/platform-browser-dynamic/testing';
+import {MatTreeModule} from '@angular/material/tree';
+import {TreeHarnessExample} from './tree-harness-example';
+import {MatIconModule} from '@angular/material/icon';
+
+describe('TreeHarnessExample', () => {
+  let fixture: ComponentFixture<TreeHarnessExample>;
+  let loader: HarnessLoader;
+
+  beforeAll(() => {
+    TestBed.initTestEnvironment(BrowserDynamicTestingModule, platformBrowserDynamicTesting());
+  });
+
+  beforeEach(
+    waitForAsync(() => {
+      TestBed.configureTestingModule({
+        imports: [MatTreeModule, MatIconModule],
+        declarations: [TreeHarnessExample]
+      }).compileComponents();
+      fixture = TestBed.createComponent(TreeHarnessExample);
+      fixture.detectChanges();
+      loader = TestbedHarnessEnvironment.loader(fixture);
+    })
+  );
+
+  it('should get correct number of children and descendants', async () => {
+    const tree = await loader.getHarness(MatTreeHarness);
+    const treeDescendants = await tree.getNodes();
+
+    // flat nodes are not rendered until expanded
+    expect(treeDescendants.length).toBe(2);
+
+    await treeDescendants[0].expand();
+
+    expect((await tree.getNodes()).length).toBe(5);
+  });
+
+  it('should correctly get correct node with text', async () => {
+    const tree = await loader.getHarness(MatTreeHarness);
+    const treeNodes = await tree.getNodes({text: /Flat Group/});
+    expect(treeNodes.length).toBe(2);
+    const secondGroup = treeNodes[0];
+
+    expect(await secondGroup.getText()).toBe('Flat Group 1');
+    expect(await secondGroup.getLevel()).toBe(1);
+    expect(await secondGroup.isDisabled()).toBe(false);
+    expect(await secondGroup.isExpanded()).toBe(false);
+  });
+
+  it ('should correctly get tree structure', async () => {
+    const tree = await loader.getHarness(MatTreeHarness);
+
+    expect(await tree.getTreeStructure()).toEqual({
+      children: [
+        {text: 'Flat Group 1'},
+        {text: 'Flat Group 2'}
+      ]
+    });
+
+    const firstGroup = (await tree.getNodes({text: /Flat Group 1/}))[0];
+    await firstGroup.expand();
+
+    expect(await tree.getTreeStructure()).toEqual({
+      children: [
+        {
+          text: 'Flat Group 1',
+          children: [
+            {text: 'Flat Leaf 1.1'},
+            {text: 'Flat Leaf 1.2'},
+            {text: 'Flat Leaf 1.3'}
+          ]
+        },
+        {text: 'Flat Group 2'}
+      ]
+    });
+  });
+});

src/components-examples/material/tree/tree-harness/tree-harness-example.ts

@@ -0,0 +1,68 @@
+import {FlatTreeControl} from '@angular/cdk/tree';
+import {Component} from '@angular/core';
+import {MatTreeFlatDataSource, MatTreeFlattener} from '@angular/material/tree';
+
+interface Node {
+  name: string;
+  children?: Node[];
+}
+
+const FLAT_TREE_DATA: Node[] = [
+  {
+    name: 'Flat Group 1',
+    children: [
+      {name: 'Flat Leaf 1.1'},
+      {name: 'Flat Leaf 1.2'},
+      {name: 'Flat Leaf 1.3'},
+    ]
+  }, {
+    name: 'Flat Group 2',
+    children: [
+      {
+        name: 'Flat Group 2.1',
+        children: [
+          {name: 'Flat Leaf 2.1.1'},
+          {name: 'Flat Leaf 2.1.2'},
+          {name: 'Flat Leaf 2.1.3'},
+        ]
+      }
+    ]
+  },
+];
+
+interface ExampleFlatNode {
+  expandable: boolean;
+  name: string;
+  level: number;
+}
+
+/**
+ * @title Testing with MatTreeHarness
+ */
+@Component({
+  selector: 'tree-harness-example',
+  templateUrl: 'tree-harness-example.html',
+})
+export class TreeHarnessExample {
+  private _transformer = (node: Node, level: number) => {
+    return {
+      expandable: !!node.children && node.children.length > 0,
+      name: node.name,
+      level: level,
+    };
+  }
+
+  treeControl = new FlatTreeControl<ExampleFlatNode>(
+      node => node.level, node => node.expandable);
+
+  treeFlattener = new MatTreeFlattener(
+      this._transformer, node => node.level, node => node.expandable, node => node.children);
+
+  dataSource = new MatTreeFlatDataSource(this.treeControl, this.treeFlattener);
+
+  constructor() {
+    this.dataSource.data = FLAT_TREE_DATA;
+  }
+
+  hasChild = (_: number, node: ExampleFlatNode) => node.expandable;
+}