feat(cdk/testing): add getNativeElement to harness environments

src/cdk/testing/protractor/protractor-harness-environment.ts

@@ -37,6 +37,14 @@ export class ProtractorHarnessEnvironment extends HarnessEnvironment<ElementFind
     return new ProtractorHarnessEnvironment(protractorElement(by.css('body')), options);
   }
 
+  /** Gets the ElementFinder corresponding to the given TestElement. */
+  static getNativeElement(el: TestElement): ElementFinder {
+    if (el instanceof ProtractorElement) {
+      return el.element;
+    }
+    throw Error('This TestElement was not created by the ProtractorHarnessEnvironment');
+  }
+
   async forceStabilize(): Promise<void> {}
 
   async waitForTasksOutsideAngular(): Promise<void> {

src/cdk/testing/testbed/testbed-harness-environment.ts

@@ -64,6 +64,14 @@ export class TestbedHarnessEnvironment extends HarnessEnvironment<Element> {
     return new TestbedHarnessEnvironment(document.body, fixture, options);
   }
 
+  /** Gets the native DOM element corresponding to the given TestElement. */
+  static getNativeElement(el: TestElement): Element {
+    if (el instanceof UnitTestElement) {
+      return el.element;
+    }
+    throw Error('This TestElement was not created by the TestbedHarnessEnvironment');
+  }
+
   /**
    * Creates an instance of the given harness type, using the fixture's root element as the
    * harness's host element. This method should be used when creating a harness for the root element

src/cdk/testing/tests/protractor.e2e.spec.ts

@@ -73,6 +73,13 @@ describe('ProtractorHarnessEnvironment', () => {
             .getHarness(MainComponentHarness);
         expect(await (await harness.deepShadow()).text()).toBe('Shadow 2');
       });
+
+      it('should be able to retrieve the ElementFinder from a ProtractorElement', async () => {
+        const harness = await ProtractorHarnessEnvironment.loader({queryFn: piercingQueryFn})
+            .getHarness(MainComponentHarness);
+        const element = ProtractorHarnessEnvironment.getNativeElement(await harness.host());
+        expect(await element.getTagName()).toBe('test-main');
+      });
     });
   });
 

src/cdk/testing/tests/testbed.spec.ts

@@ -102,6 +102,13 @@ describe('TestbedHarnessEnvironment', () => {
           );
           expect(await (await harness.deepShadow()).text()).toBe('Shadow 2');
         });
+
+        it('should be able to retrieve the native DOM element from a UnitTestElement', async () => {
+          const harness = await TestbedHarnessEnvironment
+            .harnessForFixture(fixture, MainComponentHarness);
+          const element = TestbedHarnessEnvironment.getNativeElement(await harness.host());
+          expect(element.id).toContain('root');
+        });
       });
     }
   });

tools/public_api_guard/cdk/testing/protractor.d.ts

@@ -28,6 +28,7 @@ export declare class ProtractorHarnessEnvironment extends HarnessEnvironment<Ele
     protected getAllRawElements(selector: string): Promise<ElementFinder[]>;
     protected getDocumentRoot(): ElementFinder;
     waitForTasksOutsideAngular(): Promise<void>;
+    static getNativeElement(el: TestElement): ElementFinder;
     static loader(options?: ProtractorHarnessEnvironmentOptions): HarnessLoader;
 }
 

tools/public_api_guard/cdk/testing/testbed.d.ts

@@ -7,6 +7,7 @@ export declare class TestbedHarnessEnvironment extends HarnessEnvironment<Elemen
     protected getDocumentRoot(): Element;
     waitForTasksOutsideAngular(): Promise<void>;
     static documentRootLoader(fixture: ComponentFixture<unknown>, options?: TestbedHarnessEnvironmentOptions): HarnessLoader;
+    static getNativeElement(el: TestElement): Element;
     static harnessForFixture<T extends ComponentHarness>(fixture: ComponentFixture<unknown>, harnessType: ComponentHarnessConstructor<T>, options?: TestbedHarnessEnvironmentOptions): Promise<T>;
     static loader(fixture: ComponentFixture<unknown>, options?: TestbedHarnessEnvironmentOptions): HarnessLoader;
 }