From 8e0abedbbbed281cda5b7f91fae44ea162fee0e2 Mon Sep 17 00:00:00 2001
From: Javier Feliz <javier0eduardo@hotmail.com>
Date: Thu, 31 Jul 2025 04:23:02 -0400
Subject: [PATCH] WIP

---
 tests/Feature/OIDCControllerTest.php | 401 +++++++++++++++++++++++++++
 tests/Feature/OIDCJWTTest.php        | 310 +++++++++++++++++++++
 tests/TestCase.php                   |   3 +-
 3 files changed, 713 insertions(+), 1 deletion(-)
 create mode 100644 tests/Feature/OIDCControllerTest.php
 create mode 100644 tests/Feature/OIDCJWTTest.php

diff --git a/tests/Feature/OIDCControllerTest.php b/tests/Feature/OIDCControllerTest.php
new file mode 100644
index 0000000..443ae3a
--- /dev/null
+++ b/tests/Feature/OIDCControllerTest.php
@@ -0,0 +1,401 @@
+<?php
+
+use App\Models\Application;
+use App\Models\AuthenticationToken;
+use App\Models\User;
+use Illuminate\Support\Facades\Cache;
+use Illuminate\Support\Str;
+
+beforeEach(function () {
+    $this->user = User::factory()->create([
+        'name' => 'Test User',
+        'email' => 'test@example.com',
+        'preferred_username' => 'testuser',
+    ]);
+
+    $this->application = Application::factory()->create([
+        'name' => 'Test App',
+        'client_id' => 'test-client-id',
+        'client_secret' => 'test-client-secret',
+        'redirect_uri' => 'https://example.com/callback',
+    ]);
+
+    // Create RSA key pair for testing
+    $this->createTestKeys();
+});
+
+afterEach(function () {
+    // Clean up test keys
+    $this->cleanupTestKeys();
+});
+
+// Helper function to create test RSA keys
+function createTestKeys()
+{
+    $keyDir = storage_path('oauth');
+    if (!file_exists($keyDir)) {
+        mkdir($keyDir, 0755, true);
+    }
+
+    $config = [
+        'digest_alg' => 'sha256',
+        'private_key_bits' => 2048,
+        'private_key_type' => OPENSSL_KEYTYPE_RSA,
+    ];
+
+    $privateKey = openssl_pkey_new($config);
+    openssl_pkey_export($privateKey, $privateKeyPem);
+    file_put_contents(storage_path('oauth/private.pem'), $privateKeyPem);
+
+    $publicKey = openssl_pkey_get_details($privateKey);
+    file_put_contents(storage_path('oauth/public.pem'), $publicKey['key']);
+}
+
+// Helper function to clean up test keys
+function cleanupTestKeys()
+{
+    $privateKeyPath = storage_path('oauth/private.pem');
+    $publicKeyPath = storage_path('oauth/public.pem');
+
+    if (file_exists($privateKeyPath)) {
+        unlink($privateKeyPath);
+    }
+    if (file_exists($publicKeyPath)) {
+        unlink($publicKeyPath);
+    }
+}
+
+describe('OIDC Authorization Endpoint', function () {
+    it('redirects to consent screen with valid parameters', function () {
+        $this->actingAs($this->user);
+
+        $response = $this->get('/auth/authorize?' . http_build_query([
+            'client_id' => $this->application->client_id,
+            'redirect_uri' => $this->application->redirect_uri,
+            'response_type' => 'code',
+            'scope' => 'openid email profile',
+            'state' => 'test-state',
+        ]));
+
+        $response->assertRedirect(route('auth.confirm'));
+
+        // Verify session data is set
+        $this->assertEquals($this->application->id, session('app_id'));
+        expect(session('redirect_on_confirm'))->toContain($this->application->redirect_uri);
+        expect(session('redirect_on_confirm'))->toContain('code=');
+        expect(session('redirect_on_confirm'))->toContain('state=test-state');
+    });
+
+    it('fails with invalid client_id', function () {
+        $this->actingAs($this->user);
+
+        $response = $this->get('/auth/authorize?' . http_build_query([
+            'client_id' => 'invalid-client-id',
+            'redirect_uri' => $this->application->redirect_uri,
+            'response_type' => 'code',
+        ]));
+
+        $response->assertStatus(404);
+    });
+
+    it('fails with redirect_uri mismatch', function () {
+        $this->actingAs($this->user);
+
+        $response = $this->get('/auth/authorize?' . http_build_query([
+            'client_id' => $this->application->client_id,
+            'redirect_uri' => 'https://evil.com/callback',
+            'response_type' => 'code',
+        ]));
+
+        $response->assertStatus(403);
+    });
+
+    it('requires authentication', function () {
+        $response = $this->get('/auth/authorize?' . http_build_query([
+            'client_id' => $this->application->client_id,
+            'redirect_uri' => $this->application->redirect_uri,
+            'response_type' => 'code',
+        ]));
+
+        $response->assertRedirect(route('login'));
+    });
+
+    it('supports PKCE parameters', function () {
+        $this->actingAs($this->user);
+
+        $codeVerifier = Str::random(128);
+        $codeChallenge = rtrim(strtr(base64_encode(hash('sha256', $codeVerifier, true)), '+/', '-_'), '=');
+
+        $response = $this->get('/auth/authorize?' . http_build_query([
+            'client_id' => $this->application->client_id,
+            'redirect_uri' => $this->application->redirect_uri,
+            'response_type' => 'code',
+            'code_challenge' => $codeChallenge,
+            'code_challenge_method' => 'S256',
+        ]));
+
+        $response->assertRedirect(route('auth.confirm'));
+    });
+});
+
+describe('OIDC Token Endpoint', function () {
+    beforeEach(function () {
+        // Set up authorization code in cache
+        $this->authCode = Str::random(40);
+        $this->payload = [
+            'user_id' => $this->user->id,
+            'client_id' => $this->application->id,
+            'scope' => 'openid email profile',
+            'nonce' => 'test-nonce',
+        ];
+        Cache::put("auth_code:{$this->authCode}", $this->payload, now()->addMinutes(5));
+    });
+
+    it('exchanges authorization code for tokens with client credentials', function () {
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $this->authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'client_id' => $this->application->client_id,
+            'client_secret' => $this->application->client_secret,
+        ]);
+
+        $response->assertStatus(200);
+        $data = $response->json();
+
+        expect($data)->toHaveKeys(['access_token', 'token_type', 'expires_in', 'id_token']);
+        expect($data['token_type'])->toBe('Bearer');
+        expect($data['expires_in'])->toBe(3600);
+
+        // Verify authentication token was created
+        $this->assertDatabaseHas('authentication_tokens', [
+            'user_id' => $this->user->id,
+            'application_id' => $this->application->id,
+            'token' => $data['access_token'],
+        ]);
+
+        // Verify auth code was consumed
+        expect(Cache::get("auth_code:{$this->authCode}"))->toBeNull();
+    });
+
+    it('exchanges authorization code for tokens with PKCE', function () {
+        $codeVerifier = Str::random(128);
+        $codeChallenge = rtrim(strtr(base64_encode(hash('sha256', $codeVerifier, true)), '+/', '-_'), '=');
+
+        // Update cache with PKCE parameters
+        $this->payload['code_challenge'] = $codeChallenge;
+        $this->payload['code_challenge_method'] = 'S256';
+        Cache::put("auth_code:{$this->authCode}", $this->payload, now()->addMinutes(5));
+
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $this->authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'code_verifier' => $codeVerifier,
+        ]);
+
+        $response->assertStatus(200);
+        $data = $response->json();
+
+        expect($data)->toHaveKeys(['access_token', 'token_type', 'expires_in', 'id_token']);
+    });
+
+    it('fails with invalid authorization code', function () {
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => 'invalid-code',
+            'redirect_uri' => $this->application->redirect_uri,
+            'client_id' => $this->application->client_id,
+            'client_secret' => $this->application->client_secret,
+        ]);
+
+        $response->assertStatus(403);
+    });
+
+    it('fails with expired authorization code', function () {
+        // Set expired code
+        Cache::put("auth_code:expired", $this->payload, now()->subMinute());
+
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => 'expired',
+            'redirect_uri' => $this->application->redirect_uri,
+            'client_id' => $this->application->client_id,
+            'client_secret' => $this->application->client_secret,
+        ]);
+
+        $response->assertStatus(403);
+    });
+
+    it('fails with invalid client credentials', function () {
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $this->authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'client_id' => $this->application->client_id,
+            'client_secret' => 'wrong-secret',
+        ]);
+
+        $response->assertStatus(403);
+    });
+
+    it('fails with invalid PKCE code_verifier', function () {
+        $codeChallenge = rtrim(strtr(base64_encode(hash('sha256', 'correct-verifier', true)), '+/', '-_'), '=');
+
+        $this->payload['code_challenge'] = $codeChallenge;
+        $this->payload['code_challenge_method'] = 'S256';
+        Cache::put("auth_code:{$this->authCode}", $this->payload, now()->addMinutes(5));
+
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $this->authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'code_verifier' => 'wrong-verifier',
+        ]);
+
+        $response->assertStatus(403);
+    });
+
+    it('fails with redirect_uri mismatch', function () {
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $this->authCode,
+            'redirect_uri' => 'https://evil.com/callback',
+            'client_id' => $this->application->client_id,
+            'client_secret' => $this->application->client_secret,
+        ]);
+
+        $response->assertStatus(403);
+    });
+
+    it('fails with missing authentication', function () {
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $this->authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+        ]);
+
+        $response->assertStatus(403);
+    });
+});
+
+describe('OIDC UserInfo Endpoint', function () {
+    beforeEach(function () {
+        $this->token = AuthenticationToken::create([
+            'user_id' => $this->user->id,
+            'application_id' => $this->application->id,
+            'token' => Str::random(64),
+            'issued_at' => now(),
+            'expires_at' => now()->addMonth(),
+            'ip' => '127.0.0.1',
+            'user_agent' => 'Test Agent',
+        ]);
+    });
+
+    it('returns user information with valid token', function () {
+        $response = $this->get('/auth/userinfo', [
+            'Authorization' => 'Bearer ' . $this->token->token,
+        ]);
+
+        $response->assertStatus(200);
+        $data = $response->json();
+
+        expect($data)->toBe([
+            'sub' => (string) $this->user->id,
+            'email' => $this->user->email,
+            'name' => $this->user->name,
+            'preferred_username' => $this->user->preferred_username,
+            'picture' => null, // No avatar set in test
+        ]);
+    });
+
+    it('returns user information with avatar', function () {
+        $this->user->update(['avatar' => 'test-avatar.jpg']);
+
+        $response = $this->get('/auth/userinfo', [
+            'Authorization' => 'Bearer ' . $this->token->token,
+        ]);
+
+        $response->assertStatus(200);
+        $data = $response->json();
+
+        expect($data['picture'])->toContain('test-avatar.jpg');
+    });
+
+    it('fails with missing authorization header', function () {
+        $response = $this->get('/auth/userinfo');
+
+        $response->assertStatus(400);
+        expect($response->json()['error'])->toBe('invalid_request');
+    });
+
+    it('fails with invalid authorization header format', function () {
+        $response = $this->get('/auth/userinfo', [
+            'Authorization' => 'Basic invalid-format',
+        ]);
+
+        $response->assertStatus(400);
+        expect($response->json()['error'])->toBe('invalid_request');
+    });
+
+    it('fails with invalid token', function () {
+        $response = $this->get('/auth/userinfo', [
+            'Authorization' => 'Bearer invalid-token',
+        ]);
+
+        $response->assertStatus(401);
+        expect($response->json()['error'])->toBe('invalid_token');
+    });
+});
+
+describe('OIDC JWKS Endpoint', function () {
+    it('returns public keys in JWKS format', function () {
+        $response = $this->get('/auth/keys');
+
+        $response->assertStatus(200);
+        $data = $response->json();
+
+        expect($data)->toHaveKey('keys');
+        expect($data['keys'])->toBeArray();
+        expect($data['keys'][0])->toHaveKeys(['kty', 'use', 'alg', 'kid', 'n', 'e']);
+        expect($data['keys'][0]['kty'])->toBe('RSA');
+        expect($data['keys'][0]['use'])->toBe('sig');
+        expect($data['keys'][0]['alg'])->toBe('RS256');
+    });
+});
+
+describe('OIDC OpenID Configuration', function () {
+    it('returns openid configuration', function () {
+        $response = $this->get('/.well-known/openid-configuration');
+
+        $response->assertStatus(200);
+        $data = $response->json();
+
+        $expectedKeys = [
+            'issuer',
+            'authorization_endpoint',
+            'token_endpoint',
+            'useringo_endpoint',
+            'scopes_supported',
+            'response_types_supported',
+            'jwks_uri',
+            'id_token_signing_alg_values_supported',
+            'claims_supported'
+        ];
+
+        expect($data)->toHaveKeys($expectedKeys);
+        expect($data['issuer'])->toBe(config('app.url'));
+        expect($data['scopes_supported'])->toContain('openid');
+        expect($data['response_types_supported'])->toContain('code');
+        expect($data['id_token_signing_alg_values_supported'])->toContain('RS256');
+    });
+});
+
+describe('OIDC Logout Endpoint', function () {
+    it('returns logout view', function () {
+        $response = $this->get('/auth/logout');
+
+        $response->assertStatus(200);
+        $response->assertViewIs('logged-out');
+    });
+});
diff --git a/tests/Feature/OIDCJWTTest.php b/tests/Feature/OIDCJWTTest.php
new file mode 100644
index 0000000..1c74581
--- /dev/null
+++ b/tests/Feature/OIDCJWTTest.php
@@ -0,0 +1,310 @@
+<?php
+
+use App\Models\Application;
+use App\Models\User;
+use Illuminate\Support\Facades\Cache;
+use Illuminate\Support\Str;
+use Lcobucci\JWT\Configuration;
+use Lcobucci\JWT\Signer\Key\InMemory;
+use Lcobucci\JWT\Signer\Rsa\Sha256;
+
+beforeEach(function () {
+    $this->user = User::factory()->create([
+        'name' => 'JWT Test User',
+        'email' => 'jwt@example.com',
+    ]);
+
+    $this->application = Application::factory()->create([
+        'name' => 'JWT Test App',
+        'client_id' => 'jwt-test-client',
+        'client_secret' => 'jwt-test-secret',
+        'redirect_uri' => 'https://jwt.example.com/callback',
+    ]);
+
+    // Create test keys
+    $this->createJWTTestKeys();
+});
+
+afterEach(function () {
+    $this->cleanupJWTTestKeys();
+});
+
+function createJWTTestKeys()
+{
+    $keyDir = storage_path('oauth');
+    if (!file_exists($keyDir)) {
+        mkdir($keyDir, 0755, true);
+    }
+
+    $config = [
+        'digest_alg' => 'sha256',
+        'private_key_bits' => 2048,
+        'private_key_type' => OPENSSL_KEYTYPE_RSA,
+    ];
+
+    $privateKey = openssl_pkey_new($config);
+    openssl_pkey_export($privateKey, $privateKeyPem);
+    file_put_contents(storage_path('oauth/private.pem'), $privateKeyPem);
+
+    $publicKey = openssl_pkey_get_details($privateKey);
+    file_put_contents(storage_path('oauth/public.pem'), $publicKey['key']);
+}
+
+function cleanupJWTTestKeys()
+{
+    $files = [
+        storage_path('oauth/private.pem'),
+        storage_path('oauth/public.pem')
+    ];
+
+    foreach ($files as $file) {
+        if (file_exists($file)) {
+            unlink($file);
+        }
+    }
+}
+
+describe('JWT ID Token Generation and Validation', function () {
+    it('generates valid JWT ID token', function () {
+        $this->actingAs($this->user);
+
+        // Set up authorization flow
+        $authCode = Str::random(40);
+        Cache::put("auth_code:$authCode", [
+            'user_id' => $this->user->id,
+            'client_id' => $this->application->id,
+            'scope' => 'openid email profile',
+            'nonce' => 'test-nonce-123',
+        ], now()->addMinutes(5));
+
+        // Exchange code for tokens
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'client_id' => $this->application->client_id,
+            'client_secret' => $this->application->client_secret,
+        ]);
+
+        $response->assertStatus(200);
+        $data = $response->json();
+
+        // Validate ID token structure and basic properties
+        $idToken = $data['id_token'];
+        expect($idToken)->toBeString();
+        expect(substr_count($idToken, '.'))->toBe(2); // JWT has 3 parts separated by dots
+
+        // Decode JWT payload for basic validation (without signature verification for simplicity)
+        $parts = explode('.', $idToken);
+        $payload = json_decode(base64_decode(str_pad(strtr($parts[1], '-_', '+/'), strlen($parts[1]) % 4, '=', STR_PAD_RIGHT)), true);
+
+        // Validate basic claims structure
+        expect($payload)->toHaveKeys(['iss', 'aud', 'sub', 'email', 'nonce', 'iat', 'exp']);
+        expect($payload['iss'])->toBe(config('app.url'));
+        expect($payload['aud'])->toBe($this->application->client_id);
+        expect($payload['sub'])->toBe((string) $this->user->id);
+        expect($payload['email'])->toBe($this->user->email);
+        expect($payload['nonce'])->toBe('test-nonce-123');
+
+        // Validate timing
+        expect($payload['iat'])->toBeLessThanOrEqual(time());
+        expect($payload['exp'])->toBeGreaterThan(time());
+    });
+
+    it('generates JWT without nonce when not provided', function () {
+        $this->actingAs($this->user);
+
+        $authCode = Str::random(40);
+        Cache::put("auth_code:$authCode", [
+            'user_id' => $this->user->id,
+            'client_id' => $this->application->id,
+            'scope' => 'openid email profile',
+            // No nonce provided
+        ], now()->addMinutes(5));
+
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'client_id' => $this->application->client_id,
+            'client_secret' => $this->application->client_secret,
+        ]);
+
+        $response->assertStatus(200);
+        $data = $response->json();
+
+        // Parse JWT payload for basic validation
+        $parts = explode('.', $data['id_token']);
+        $payload = json_decode(base64_decode(str_pad(strtr($parts[1], '-_', '+/'), strlen($parts[1]) % 4, '=', STR_PAD_RIGHT)), true);
+
+        // Verify nonce claim is not present
+        expect($payload)->not->toHaveKey('nonce');
+    });
+
+    it('JWT expires in 5 minutes', function () {
+        $this->actingAs($this->user);
+
+        $authCode = Str::random(40);
+        Cache::put("auth_code:$authCode", [
+            'user_id' => $this->user->id,
+            'client_id' => $this->application->id,
+            'scope' => 'openid email profile',
+        ], now()->addMinutes(5));
+
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'client_id' => $this->application->client_id,
+            'client_secret' => $this->application->client_secret,
+        ]);
+
+        $data = $response->json();
+
+        // Parse JWT payload
+        $parts = explode('.', $data['id_token']);
+        $payload = json_decode(base64_decode(str_pad(strtr($parts[1], '-_', '+/'), strlen($parts[1]) % 4, '=', STR_PAD_RIGHT)), true);
+
+        // Should expire in 5 minutes (300 seconds)
+        expect($payload['exp'] - $payload['iat'])->toBe(300);
+    });
+});
+
+describe('PKCE Code Challenge Validation', function () {
+    it('validates S256 code challenge correctly', function () {
+        $this->actingAs($this->user);
+
+        $codeVerifier = Str::random(128);
+        $codeChallenge = rtrim(strtr(base64_encode(hash('sha256', $codeVerifier, true)), '+/', '-_'), '=');
+
+        $authCode = Str::random(40);
+        Cache::put("auth_code:$authCode", [
+            'user_id' => $this->user->id,
+            'client_id' => $this->application->id,
+            'scope' => 'openid',
+            'code_challenge' => $codeChallenge,
+            'code_challenge_method' => 'S256',
+        ], now()->addMinutes(5));
+
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'code_verifier' => $codeVerifier,
+        ]);
+
+        $response->assertStatus(200);
+    });
+
+    it('validates plain code challenge correctly', function () {
+        $this->actingAs($this->user);
+
+        $codeVerifier = 'plain-text-verifier';
+
+        $authCode = Str::random(40);
+        Cache::put("auth_code:$authCode", [
+            'user_id' => $this->user->id,
+            'client_id' => $this->application->id,
+            'scope' => 'openid',
+            'code_challenge' => $codeVerifier,
+            'code_challenge_method' => 'plain',
+        ], now()->addMinutes(5));
+
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'code_verifier' => $codeVerifier,
+        ]);
+
+        $response->assertStatus(200);
+    });
+
+    it('rejects invalid code challenge method', function () {
+        $this->actingAs($this->user);
+
+        $authCode = Str::random(40);
+        Cache::put("auth_code:$authCode", [
+            'user_id' => $this->user->id,
+            'client_id' => $this->application->id,
+            'scope' => 'openid',
+            'code_challenge' => 'some-challenge',
+            'code_challenge_method' => 'invalid-method',
+        ], now()->addMinutes(5));
+
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'code_verifier' => 'some-verifier',
+        ]);
+
+        $response->assertStatus(403);
+    });
+});
+
+describe('Access Token Management', function () {
+    it('creates authentication token record with correct metadata', function () {
+        $this->actingAs($this->user);
+
+        $authCode = Str::random(40);
+        Cache::put("auth_code:$authCode", [
+            'user_id' => $this->user->id,
+            'client_id' => $this->application->id,
+            'scope' => 'openid email profile',
+        ], now()->addMinutes(5));
+
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'client_id' => $this->application->client_id,
+            'client_secret' => $this->application->client_secret,
+        ], [
+            'User-Agent' => 'Test Browser/1.0',
+        ]);
+
+        $response->assertStatus(200);
+        $data = $response->json();
+
+        // Verify token record was created with metadata
+        $tokenRecord = $this->user->tokens()->where('token', $data['access_token'])->first();
+
+        expect($tokenRecord)->not->toBeNull();
+        expect($tokenRecord->application_id)->toBe($this->application->id);
+        expect($tokenRecord->ip)->toBe('127.0.0.1'); // Default test IP
+        expect($tokenRecord->user_agent)->toBe('Test Browser/1.0');
+        expect($tokenRecord->issued_at)->not->toBeNull();
+        expect($tokenRecord->expires_at)->not->toBeNull();
+    });
+
+    it('sets access token expiration to 1 month', function () {
+        $this->actingAs($this->user);
+
+        $authCode = Str::random(40);
+        Cache::put("auth_code:$authCode", [
+            'user_id' => $this->user->id,
+            'client_id' => $this->application->id,
+            'scope' => 'openid',
+        ], now()->addMinutes(5));
+
+        $before = now();
+
+        $response = $this->post('/auth/token', [
+            'grant_type' => 'authorization_code',
+            'code' => $authCode,
+            'redirect_uri' => $this->application->redirect_uri,
+            'client_id' => $this->application->client_id,
+            'client_secret' => $this->application->client_secret,
+        ]);
+
+        $after = now();
+        $data = $response->json();
+
+        $tokenRecord = $this->user->tokens()->where('token', $data['access_token'])->first();
+
+        // Token should expire approximately 1 month from now
+        $expectedExpiry = $before->addMonth();
+        expect($tokenRecord->expires_at)->toBeBetween($expectedExpiry, $after->addMonth());
+    });
+});
diff --git a/tests/TestCase.php b/tests/TestCase.php
index fe1ffc2..d7c5d5f 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -2,9 +2,10 @@
 
 namespace Tests;
 
+use Illuminate\Foundation\Testing\RefreshDatabase;
 use Illuminate\Foundation\Testing\TestCase as BaseTestCase;
 
 abstract class TestCase extends BaseTestCase
 {
-    //
+    use RefreshDatabase;
 }