diff --git a/tests/legacy-cli/e2e/tests/vitest/larger-project.ts b/tests/legacy-cli/e2e/tests/vitest/larger-project.ts
new file mode 100644
index 000000000000..16d254f98a24
--- /dev/null
+++ b/tests/legacy-cli/e2e/tests/vitest/larger-project.ts
@@ -0,0 +1,60 @@
+import { ng } from '../../utils/process';
+import { applyVitestBuilder } from '../../utils/vitest';
+import assert from 'node:assert';
+import { installPackage } from '../../utils/packages';
+import { exec } from '../../utils/process';
+
+export default async function () {
+  await applyVitestBuilder();
+
+  const artifactCount = 100;
+  // A new project starts with 1 test file (app.spec.ts)
+  // Each generated artifact will add one more test file.
+  const initialTestCount = 1;
+
+  // Generate a mix of components, services, and pipes
+  for (let i = 0; i < artifactCount; i++) {
+    const type = i % 3;
+    const name = `test-artifact-${i}`;
+    let generateType;
+
+    switch (type) {
+      case 0:
+        generateType = 'component';
+        break;
+      case 1:
+        generateType = 'service';
+        break;
+      default:
+        generateType = 'pipe';
+        break;
+    }
+
+    await ng('generate', generateType, name, '--skip-tests=false');
+  }
+
+  const totalTests = initialTestCount + artifactCount;
+  const expectedMessage = new RegExp(`${totalTests} passed`);
+
+  // Run tests in default (JSDOM) mode
+  const { stdout: jsdomStdout } = await ng('test', '--no-watch');
+  assert.match(jsdomStdout, expectedMessage, `Expected ${totalTests} tests to pass in JSDOM mode.`);
+
+  // Setup for browser mode
+  await installPackage('playwright@1');
+  await installPackage('@vitest/browser-playwright@4');
+  await exec('npx', 'playwright', 'install', 'chromium', '--only-shell');
+
+  // Run tests in browser mode
+  const { stdout: browserStdout } = await ng(
+    'test',
+    '--no-watch',
+    '--browsers',
+    'ChromiumHeadless',
+  );
+  assert.match(
+    browserStdout,
+    expectedMessage,
+    `Expected ${totalTests} tests to pass in browser mode.`,
+  );
+}
diff --git a/tests/legacy-cli/e2e/tests/vitest/tslib-resolution.ts b/tests/legacy-cli/e2e/tests/vitest/tslib-resolution.ts
new file mode 100644
index 000000000000..d3cb95a3ef3c
--- /dev/null
+++ b/tests/legacy-cli/e2e/tests/vitest/tslib-resolution.ts
@@ -0,0 +1,72 @@
+import { writeFile } from '../../utils/fs';
+import { installPackage } from '../../utils/packages';
+import { exec, ng } from '../../utils/process';
+import { applyVitestBuilder } from '../../utils/vitest';
+import assert from 'node:assert';
+
+export default async function () {
+  await applyVitestBuilder();
+  await installPackage('playwright@1');
+  await installPackage('@vitest/browser-playwright@4');
+  await exec('npx', 'playwright', 'install', 'chromium', '--only-shell');
+
+  // Add a custom decorator to trigger tslib usage
+  await writeFile(
+    'src/app/custom-decorator.ts',
+    `
+    export function MyDecorator() {
+      return function (target: any, propertyKey: string, descriptor: PropertyDescriptor) {
+        // do nothing
+      };
+    }
+    `,
+  );
+
+  // Add a service that uses the decorator
+  await writeFile(
+    'src/app/test.service.ts',
+    `
+    import { Injectable } from '@angular/core';
+    import { MyDecorator } from './custom-decorator';
+
+    @Injectable({
+      providedIn: 'root'
+    })
+    export class TestService {
+      @MyDecorator()
+      myMethod() {
+        return true;
+      }
+    }
+    `,
+  );
+
+  // Add a test for the service
+  await writeFile(
+    'src/app/test.service.spec.ts',
+    `
+    import { TestBed } from '@angular/core/testing';
+    import { TestService } from './test.service';
+
+    describe('TestService', () => {
+      let service: TestService;
+
+      beforeEach(() => {
+        TestBed.configureTestingModule({});
+        service = TestBed.inject(TestService);
+      });
+
+      it('should be created', () => {
+        expect(service).toBeTruthy();
+      });
+
+      it('myMethod should return true', () => {
+        expect(service.myMethod()).toBe(true);
+      });
+    });
+    `,
+  );
+
+  const { stdout } = await ng('test', '--no-watch', '--browsers', 'chromiumHeadless');
+  assert.match(stdout, /2 passed/, 'Expected 2 tests to pass.');
+}