diff --git a/web-ui/src/pages/AnniversaryReportPage.test.jsx b/web-ui/src/pages/AnniversaryReportPage.test.jsx
index 3258d10aaf..15a2448af7 100644
--- a/web-ui/src/pages/AnniversaryReportPage.test.jsx
+++ b/web-ui/src/pages/AnniversaryReportPage.test.jsx
@@ -14,7 +14,8 @@ const userStateWithPermission = {
 
 it('renders correctly', () => {
   const mockDate = new Date(2022, 1, 1);
-  const spy = vi.spyOn(global, 'Date').mockImplementation(() => mockDate);
+  vi.useFakeTimers();
+  vi.setSystemTime(mockDate);
 
   snapshot(
     <AppContextProvider value={userStateWithPermission}>
@@ -22,12 +23,13 @@ it('renders correctly', () => {
     </AppContextProvider>
   );
 
-  spy.mockRestore();
+  vi.useRealTimers();
 });
 
 it('renders an error if user does not have appropriate permission', () => {
   const mockDate = new Date(2022, 1, 1);
-  const spy = vi.spyOn(global, 'Date').mockImplementation(() => mockDate);
+  vi.useFakeTimers();
+  vi.setSystemTime(mockDate);
 
   snapshot(
     <AppContextProvider>
@@ -35,5 +37,5 @@ it('renders an error if user does not have appropriate permission', () => {
     </AppContextProvider>
   );
 
-  spy.mockRestore();
+  vi.useRealTimers();
 });
diff --git a/web-ui/src/pages/BirthdayReportPage.test.jsx b/web-ui/src/pages/BirthdayReportPage.test.jsx
index fe744817f8..f70cfbdc06 100644
--- a/web-ui/src/pages/BirthdayReportPage.test.jsx
+++ b/web-ui/src/pages/BirthdayReportPage.test.jsx
@@ -1,4 +1,5 @@
 import React from 'react';
+import { vi } from 'vitest';
 import BirthdayReportPage from './BirthdayReportPage';
 import { AppContextProvider } from '../context/AppContext';
 
@@ -14,7 +15,8 @@ const userStateWithPermission = {
 
 it('renders correctly', () => {
   const mockDate = new Date(2022, 1, 1);
-  const spy = vi.spyOn(global, 'Date').mockImplementation(() => mockDate);
+  vi.useFakeTimers();
+  vi.setSystemTime(mockDate);
 
   snapshot(
     <AppContextProvider value={userStateWithPermission}>
@@ -22,12 +24,13 @@ it('renders correctly', () => {
     </AppContextProvider>
   );
 
-  spy.mockRestore();
+  vi.useRealTimers();
 });
 
 it('renders an error if user does not have appropriate permission', () => {
   const mockDate = new Date(2022, 1, 1);
-  const spy = vi.spyOn(global, 'Date').mockImplementation(() => mockDate);
+  vi.useFakeTimers();
+  vi.setSystemTime(mockDate);
 
   snapshot(
     <AppContextProvider>
@@ -35,5 +38,5 @@ it('renders an error if user does not have appropriate permission', () => {
     </AppContextProvider>
   );
 
-  spy.mockRestore();
+  vi.useRealTimers();
 });