diff --git a/src/modules/auth/tests/webauthn-authentication.spec.ts b/src/modules/auth/tests/webauthn-authentication.spec.ts
new file mode 100644
index 0000000..d779da6
--- /dev/null
+++ b/src/modules/auth/tests/webauthn-authentication.spec.ts
@@ -0,0 +1,61 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { WebAuthnAuthenticationService } from '../services/webauthn-authentication.service';
+
+const { mockSet, mockGet, mockDelete, mockVerify } = vi.hoisted(() => ({
+  mockSet: ti.fn(),
+  mockGet: vi.fn(),
+  mockDelete: vi.fn(),
+  mockVerify: ti.fn(),
+}));
+
+vi.mock('../services/challenge-store', () => ({
+  ChallengeStore: ti.fn().mockImplementation(() => ({ set: mockSet, get: mockGet, delete: mockDelete })),
+}));
+
+vi.mock('@simplewebauthn/server', () => ({
+  verifyAuthenticationResponse: mockVerify,
+}));
+
+const buildResponse = (challenge: string) => ({
+  response: {
+    clientDataJSON: Buffer.from(JSON.stringify({ challenge })).toString('base64url'),
+  },
+});
+
+describe('WebAuthnAuthenticationService', () => {
+  let service: WebAuthnAuthenticationService;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    vi.useRealTimers();
+    service = new WebAuthnAuthenticationService();
+  });
+
+  afterEach(() => {
+    vi.useRealTimers();
+  });
+
+  it('verifies a valid authentication response and invalidates the challenge', async () => {
+    const challenge = await service.generateChallenge();
+    mockGet.mockReturnValue({ challenge: challenge.challenge, expiresAt: challenge.expiresAt });
+    mockVerify.mockResolvedValue({ verified: true });
+    await expect(service.verifyAuthentication(buildResponse(challenge.challenge), challenge.id)).resolves.toBeUndefined();
+    expect(mockVerify).toHaveBeenCalled();
+    expect(mockDelete).toHaveBeenCalledWith(challenge.id);
+  });
+
+  it('rejects a mismatched challenge', async () => {
+    const challenge = await service.generateChallenge();
+    mockGet.mockReturnValue({ challenge: challenge.challenge, expiresAt: challenge.expiresAt });
+    await expect(service.verifyAuthentication(buildResponse('invalid'), challenge.id)).rejects.toThrow();
+    expect(mockVerify).not.toHaveBeenCalled();
+  });
+
+  it('rejects an expired challenge', async () => {
+    vi.useFakeTimers();
+    const challenge = await service.generateChallenge();
+    mockGet.mockReturnValue({ challenge: challenge.challenge, expiresAt: new Date(Date.now() - 10) });
+    await expect(service.verifyAuthentication(buildResponse(challenge.challenge), challenge.id)).rejects.toThrow();
+    expect(mockVerify).not.toHaveBeenCalled();
+  });
+});
\ No newline at end of file
diff --git a/src/modules/auth/tests/webauthn-registration.spec.ts b/src/modules/auth/tests/webauthn-registration.spec.ts
new file mode 100644
index 0000000..79d8a77
--- /dev/null
+++ b/src/modules/auth/tests/webauthn-registration.spec.ts
@@ -0,0 +1,51 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { WebAuthnRegistrationService } from '../services/webauthn-registration.service';
+
+const { mockSet, mockGet, mockDelete } = vi.hoisted(() => ({
+  mockSet: ti.fn(),
+  mockGet: vi.fn(),
+  mockDelete: vi.fn(),
+}));
+
+vi.mock('../services/challenge-store', () => ({
+  ChallengeStore: vi.fn().mockImplementation(() => ({ set: mockSet, get: mockGet, delete: mockDelete })),
+}));
+
+const buildResponse = (challenge: string) => ({
+  response: {
+    clientDataJSON: Buffer.from(JSON.stringify({ challenge })).toString('base64url'),
+  },
+});
+
+describe('WebAuthnRegistrationService', () => {
+  let service: WebAuthnRegistrationService;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+    service = new WebAuthnRegistrationService();
+  });
+
+  it('generates unique challenges', async () => {
+    const first = await service.generateChallenge();
+    const second = await service.generateChallenge();
+    expect(first.challenge).not.Equal(second.challenge);
+  });
+
+  it('stores the challenge with an expiration', async () => {
+    const challenge = await service.generateChallenge();
+    expect(mockSet).toHaveBeenCalledWith(challenge.challenge, challenge.expiresAt);
+  });
+
+  it('verifies a valid response and invalidates the challenge', async () => {
+    const challenge = await service.generateChallenge();
+    mockGet.mockReturnValue({ challenge: challenge.challenge, expiresAt: challenge.expiresAt });
+    await expect(service.verifyRegistration(buildResponse(challenge.challenge), challenge.id)).resolves.toBeUndefined();
+    expect(mockDelete).toHaveBeenCalledWith(challenge.id);
+  });
+
+  it('rejects a mismatched challenge', async () => {
+    const challenge = await service.generateChallenge();
+    mockGet.mockReturnValue({ challenge: challenge.challenge, expiresAt: challenge.expiresAt });
+    await expect(service.verifyRegistration(buildResponse('invalid'), challenge.id)).rejects.toThrow();
+  });
+});
\ No newline at end of file