diff --git a/packages/backend/src/helpers/authentication.test.js b/packages/backend/src/helpers/authentication.test.js
new file mode 100644
index 00000000..1b5f1620
--- /dev/null
+++ b/packages/backend/src/helpers/authentication.test.js
@@ -0,0 +1,33 @@
+import { describe, it, expect } from 'vitest';
+import { isAuthenticated } from './authentication.js';
+import { createUser } from '../../test/factories/user.js';
+import createAuthTokenByUserId from '../helpers/create-auth-token-by-user-id.js';
+
+describe('isAuthenticated', () => {
+  it('should return false if no token is provided', async () => {
+    const req = { headers: {} };
+    expect(await isAuthenticated(req)).toBe(false);
+  });
+
+  it('should return false if token is invalid', async () => {
+    const req = { headers: { authorization: 'invalidToken' } };
+    expect(await isAuthenticated(req)).toBe(false);
+  });
+
+  it('should return true if token is valid and there is a user', async () => {
+    const user = await createUser();
+    const token = await createAuthTokenByUserId(user.id);
+
+    const req = { headers: { authorization: token } };
+    expect(await isAuthenticated(req)).toBe(true);
+  });
+
+  it('should return false if token is valid and but there is no user', async () => {
+    const user = await createUser();
+    const token = await createAuthTokenByUserId(user.id);
+    await user.$query().delete();
+
+    const req = { headers: { authorization: token } };
+    expect(await isAuthenticated(req)).toBe(false);
+  });
+});