diff --git a/server/tests/routes/auth.test.js b/server/tests/routes/auth.test.js
index ea03848..41b2fc5 100644
--- a/server/tests/routes/auth.test.js
+++ b/server/tests/routes/auth.test.js
@@ -4,6 +4,7 @@ const sinon = require('sinon');
 const request = require('supertest');
 const express = require('express');
 const { setupTestEnvironment, teardownTestEnvironment, cleanDatabase, createTestUser, createTestTenant, generateTestToken } = require('../setup');
+const { createTenantRequest, TEST_TENANTS } = require('../utils/testDomains');
 const authRoutes = require('../../routes/auth');
 
 describe('Auth Routes', () => {
@@ -28,16 +29,18 @@ describe('Auth Routes', () => {
 
   describe('POST /auth/login', () => {
     it('should login with valid credentials', async () => {
-      const tenant = await createTestTenant({ slug: 'test-tenant' });
+      const tenant = await createTestTenant({ slug: TEST_TENANTS.DEFAULT });
+      console.log('🔧 TEST: Created tenant:', { id: tenant.id, slug: tenant.slug });
+      
       const user = await createTestUser({
         username: 'testuser',
         password: '$2b$10$92IXUNpkjO0rOQ5byMi.Ye4oKoEa3Ro9llC/.og/at2.uheWG/igi', // password
         tenant_id: tenant.id
       });
+      console.log('🔧 TEST: Created user:', { id: user.id, username: user.username, tenant_id: user.tenant_id });
 
-      const response = await request(app)
+      const response = await createTenantRequest(request, app, TEST_TENANTS.DEFAULT)
         .post('/auth/login')
-        .set('Host', 'test-tenant.example.com') // Use fake domain for subdomain extraction
         .send({
           username: 'testuser',
           password: 'password'
diff --git a/server/tests/utils/testDomains.js b/server/tests/utils/testDomains.js
new file mode 100644
index 0000000..c10f30a
--- /dev/null
+++ b/server/tests/utils/testDomains.js
@@ -0,0 +1,38 @@
+/**
+ * Test Domain Utilities
+ * Standardizes fake domain usage across all tests for multi-tenant scenarios
+ */
+
+/**
+ * Generate a fake domain for a tenant slug
+ * @param {string} tenantSlug - The tenant slug (e.g., 'test-tenant')
+ * @returns {string} - The fake domain (e.g., 'test-tenant.example.com')
+ */
+function getTenantDomain(tenantSlug) {
+  return `${tenantSlug}.example.com`;
+}
+
+/**
+ * Create a supertest request with proper tenant domain
+ * @param {Object} app - Express app instance
+ * @param {string} tenantSlug - The tenant slug
+ * @returns {Object} - Request object with Host header set
+ */
+function createTenantRequest(request, app, tenantSlug) {
+  return request(app).set('Host', getTenantDomain(tenantSlug));
+}
+
+/**
+ * Standard test tenant configurations
+ */
+const TEST_TENANTS = {
+  DEFAULT: 'test-tenant',
+  SECONDARY: 'test-tenant-2',
+  ADMIN: 'admin-tenant'
+};
+
+module.exports = {
+  getTenantDomain,
+  createTenantRequest,
+  TEST_TENANTS
+};