thePunderWoman · Nov 12, 2026 · Nov 11, 2026
diff --git a/packages/core/src/application/application_tokens.ts b/packages/core/src/application/application_tokens.ts
@@ -51,6 +51,16 @@ export const APP_ID = new InjectionToken<string>(
 /** Default value of the `APP_ID` token. */
 const DEFAULT_APP_ID = 'ng';
 
+/**
+ * Internal token that indicates whether the application is running in a test environment (e.g. TestBed).
+ */
+export const IS_TESTING = new InjectionToken<boolean>(
+  typeof ngDevMode !== 'undefined' && ngDevMode ? 'IS_TESTING' : '',
+  {
+    factory: () => false,
+  },
+);
+
 /** Initializer check for the validity of the APP_ID */
 export const validAppIdInitializer: StaticProvider = {
   provide: ENVIRONMENT_INITIALIZER,

diff --git a/packages/core/src/core_private_export.ts b/packages/core/src/core_private_export.ts
@@ -29,6 +29,7 @@ export {
   IMAGE_CONFIG as ɵIMAGE_CONFIG,
   IMAGE_CONFIG_DEFAULTS as ɵIMAGE_CONFIG_DEFAULTS,
   ImageConfig as ɵImageConfig,
+  IS_TESTING as ɵIS_TESTING,
 } from './application/application_tokens';
 export {internalCreateApplication as ɵinternalCreateApplication} from './application/create_application';
 export {

diff --git a/packages/core/src/defer/instructions.ts b/packages/core/src/defer/instructions.ts
@@ -7,6 +7,7 @@
  */
 
 import {setActiveConsumer} from '../../primitives/signals';
+import {IS_TESTING} from '../application/application_tokens';
 
 import {
   DEFER_BLOCK_ID,
@@ -148,7 +149,11 @@ export function ɵɵdefer(
       if (typeof ngHmrMode !== 'undefined' && ngHmrMode) {
         logHmrWarning(injector);
       }
-      if (hasHydrateTriggers(flags) && !incrementalHydrationEnabled) {
+      if (
+        hasHydrateTriggers(flags) &&
+        !incrementalHydrationEnabled &&
+        !injector.get(IS_TESTING, false)
+      ) {
         warnIncrementalHydrationNotConfigured();
       }
     }

diff --git a/packages/core/src/hydration/api.ts b/packages/core/src/hydration/api.ts
@@ -7,6 +7,7 @@
  */
 
 import {APP_BOOTSTRAP_LISTENER, ApplicationRef} from '../application/application_ref';
+import {IS_TESTING} from '../application/application_tokens';
 import {Console} from '../console';
 import {
   ENVIRONMENT_INITIALIZER,
@@ -230,6 +231,7 @@ export function withDomHydration(): EnvironmentProviders {
         } else if (
           typeof ngDevMode !== 'undefined' &&
           ngDevMode &&
+          !inject(IS_TESTING) &&
           !isClientRenderModeEnabled(doc)
         ) {
           const console = inject(Console);

diff --git a/packages/core/testing/src/test_bed_compiler.ts b/packages/core/testing/src/test_bed_compiler.ts
@@ -9,6 +9,7 @@
 import {ResourceLoader} from '@angular/compiler';
 import {
   ɵANIMATIONS_DISABLED as ANIMATIONS_DISABLED,
+  ɵIS_TESTING as IS_TESTING,
   ApplicationInitStatus,
   ɵcompileComponent as compileComponent,
   ɵcompileDirective as compileDirective,
@@ -995,6 +996,7 @@ export class TestBedCompiler {
         provide: ANIMATIONS_DISABLED,
         useValue: !this.animationsEnabled,
       },
+      {provide: IS_TESTING, useValue: true},
       {
         provide: INTERNAL_APPLICATION_ERROR_HANDLER,
         useFactory: () => {

diff --git a/packages/platform-browser/test/hydration_spec.ts b/packages/platform-browser/test/hydration_spec.ts
@@ -14,6 +14,8 @@ import {
   Component,
   Injectable,
   PLATFORM_ID,
+  ɵIS_TESTING as IS_TESTING,
+  ɵresetIncrementalHydrationEnabledWarnedForTests as resetIncrementalHydrationEnabledWarnedForTests,
   ɵSSR_CONTENT_INTEGRITY_MARKER as SSR_CONTENT_INTEGRITY_MARKER,
 } from '@angular/core';
 import {TestBed} from '@angular/core/testing';
@@ -173,4 +175,54 @@ describe('provideClientHydration', () => {
       }).toThrowError(/Configuration error: found both withIncrementalHydration/);
     });
   });
+
+  describe('in TestBed', () => {
+    beforeEach(() => {
+      globalThis['ngServerMode'] = undefined;
+    });
+
+    it('should not log NG0505 warning when provideClientHydration is used in TestBed', () => {
+      const consoleSpy = spyOn(console, 'warn');
+      TestBed.resetTestingModule();
+      TestBed.configureTestingModule({
+        providers: [provideClientHydration()],
+      });
+      TestBed.createComponent(SomeComponent);
+      expect(consoleSpy).not.toHaveBeenCalledWith(
+        jasmine.stringMatching('NG0505: Angular hydration was requested on the client'),
+      );
+    });
+
+    it('should not log NG0508 warning when defer block with hydrate triggers is used in TestBed without hydration providers', () => {
+      resetIncrementalHydrationEnabledWarnedForTests();
+      @Component({
+        template: `
+          @defer (hydrate on idle) {
+            <p>Defer hydrated</p>
+          }
+        `,
+      })
+      class DeferHydrateComponent {}
+
+      const consoleSpy = spyOn(console, 'warn');
+      TestBed.resetTestingModule();
+      TestBed.configureTestingModule({
+        imports: [DeferHydrateComponent],
+      });
+      TestBed.createComponent(DeferHydrateComponent);
+      expect(consoleSpy).not.toHaveBeenCalledWith(jasmine.stringMatching('NG0508'));
+    });
+
+    it('should log NG0505 warning if IS_TESTING is explicitly false and no serialized info is present', () => {
+      const consoleSpy = spyOn(console, 'warn');
+      TestBed.resetTestingModule();
+      TestBed.configureTestingModule({
+        providers: [provideClientHydration(), {provide: IS_TESTING, useValue: false}],
+      });
+      TestBed.createComponent(SomeComponent);
+      expect(consoleSpy).toHaveBeenCalledWith(
+        jasmine.stringMatching('NG0505: Angular hydration was requested on the client'),
+      );
+    });
+  });
 });
diff --git a/packages/platform-browser/testing/src/browser.ts b/packages/platform-browser/testing/src/browser.ts
@@ -6,7 +6,14 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 import {ɵprovideFakePlatformNavigation} from '@angular/common/testing';
-import {APP_ID, createPlatformFactory, NgModule, StaticProvider, PlatformRef} from '@angular/core';
+import {
+  APP_ID,
+  createPlatformFactory,
+  NgModule,
+  StaticProvider,
+  PlatformRef,
+  ɵIS_TESTING as IS_TESTING,
+} from '@angular/core';
 import {TestComponentRenderer} from '@angular/core/testing';
 // g3-only import {BrowserModule, platformBrowser} from '@angular/platform-browser';
 import {BrowserModule, platformBrowser} from '../../index'; // 3p-only
@@ -29,6 +36,7 @@ export const platformBrowserTesting: (extraProviders?: StaticProvider[]) => Plat
   exports: [BrowserModule],
   providers: [
     {provide: APP_ID, useValue: 'a'},
+    {provide: IS_TESTING, useValue: true},
     ɵprovideFakePlatformNavigation(),
     {provide: TestComponentRenderer, useClass: DOMTestComponentRenderer},
   ],