diff --git a/angular.json b/angular.json
index 34b6633f9..d4d624a90 100644
--- a/angular.json
+++ b/angular.json
@@ -209,7 +209,7 @@
           "builder": "@angular-devkit/build-angular:karma",
           "options": {
             "main": "src/test.ts",
-            "polyfills": "src/polyfills.ts",
+            "polyfills": ["zone.js", "zone.js/testing", "src/polyfills.ts"],
             "tsConfig": "src/tsconfig.spec.json",
             "preserveSymlinks": true,
             "karmaConfig": "src/karma.conf.js",
diff --git a/src/app/features/project/project.service.spec.ts b/src/app/features/project/project.service.spec.ts
index 6d88a3761..4c10aefa0 100644
--- a/src/app/features/project/project.service.spec.ts
+++ b/src/app/features/project/project.service.spec.ts
@@ -150,6 +150,11 @@ describe('ProjectService', () => {
     store.overrideSelector(selectNoteFeatureState, initialNoteState);
   });
 
+  afterEach(() => {
+    // Reset selector mocks to prevent interference with other test files
+    store.resetSelectors();
+  });
+
   it('should be created', () => {
     expect(service).toBeTruthy();
   });
diff --git a/src/test.ts b/src/test.ts
index d9eba7ef8..d45aa445b 100644
--- a/src/test.ts
+++ b/src/test.ts
@@ -1,7 +1,8 @@
 // This file is required by karma.conf.js and loads recursively all the .spec and framework files
 
-import 'zone.js';
-import 'zone.js/testing';
+// NOTE: Do NOT import 'zone.js' or 'zone.js/testing' here explicitly.
+// Angular's karma builder handles Zone.js setup automatically.
+// Adding explicit imports causes conflicts with Jasmine's clock mocking.
 import { getTestBed, TestBed } from '@angular/core/testing';
 import {
   BrowserDynamicTestingModule,