feat(material-experimental/mdc-list): add support for activated state in harness (#24934)

Author: mmalerba

src/material-experimental/mdc-list/testing/list-harness-filters.ts

@@ -34,6 +34,7 @@ export interface ActionListItemHarnessFilters extends BaseListItemHarnessFilters
 
 export interface NavListItemHarnessFilters extends BaseListItemHarnessFilters {
   href?: string | RegExp | null;
+  activated?: boolean;
 }
 
 export interface ListOptionHarnessFilters extends BaseListItemHarnessFilters {

src/material-experimental/mdc-list/testing/list-harness.spec.ts

@@ -394,6 +394,20 @@ describe('MatNavListHarness', () => {
       expect(items.length).toBe(1);
       expect(await items[0].getHref()).toBe('/somestuff');
     });
+
+    it('should get activated state', async () => {
+      const items = await harness.getItems();
+      const activated = await parallel(() => items.map(item => item.isActivated()));
+      expect(activated).toEqual([false, true, false, false, false]);
+    });
+
+    it('should get item harness by activated state', async () => {
+      const activatedItems = await harness.getItems({activated: true});
+      const activatedItemsText = await parallel(() =>
+        activatedItems.map(item => item.getFullText()),
+      );
+      expect(activatedItemsText).toEqual(['Item 2']);
+    });
   });
 });
 
@@ -587,7 +601,7 @@ class ActionListHarnessTest {
         </a>
         <div matSubheader>Section 1</div>
         <mat-divider></mat-divider>
-        <a mat-list-item href (click)="onClick($event, 'Item 2')">
+        <a mat-list-item activated href (click)="onClick($event, 'Item 2')">
           <span class="test-item-content">Item 2</span>
         </a>
         <a

src/material-experimental/mdc-list/testing/nav-list-harness.ts

@@ -51,11 +51,15 @@ export class MatNavListItemHarness extends MatListItemHarnessBase {
     this: ComponentHarnessConstructor<T>,
     options: NavListItemHarnessFilters = {},
   ): HarnessPredicate<T> {
-    return getListItemPredicate(this, options).addOption(
-      'href',
-      options.href,
-      async (harness, href) => HarnessPredicate.stringMatches(harness.getHref(), href),
-    );
+    return getListItemPredicate(this, options)
+      .addOption('href', options.href, async (harness, href) =>
+        HarnessPredicate.stringMatches(harness.getHref(), href),
+      )
+      .addOption(
+        'activated',
+        options.activated,
+        async (harness, activated) => (await harness.isActivated()) === activated,
+      );
   }
 
   /** Gets the href for this nav list item. */
@@ -82,4 +86,9 @@ export class MatNavListItemHarness extends MatListItemHarnessBase {
   async isFocused(): Promise<boolean> {
     return (await this.host()).isFocused();
   }
+
+  /** Whether the list item is activated. Should only be used for nav list items. */
+  async isActivated(): Promise<boolean> {
+    return (await this.host()).hasClass('mdc-list-item--activated');
+  }
 }