update

readme.hints.md

@@ -209,4 +209,55 @@ emailConfig: {
 ### TLS Handling
 - Ports 25 and 587: Use 'passthrough' mode (STARTTLS handled by email server)
 - Port 465: Use 'terminate' mode (SmartProxy handles TLS termination)
-- Domain-specific TLS can be configured per email rule
+- Domain-specific TLS can be configured per email rule
+
+## SMTP Test Migration
+
+### Test Framework
+- Tests migrated from custom framework to @push.rocks/tapbundle
+- Each test file is self-contained with its own server lifecycle management
+- Test files use pattern `test.*.ts` for automatic discovery by tstest
+
+### Server Lifecycle
+- SMTP server uses `listen()` method to start (not `start()`)
+- SMTP server uses `close()` method to stop (not `stop()` or `destroy()`)
+- Server loader module manages server lifecycle for tests
+
+### Test Structure
+```typescript
+import { expect, tap } from '@push.rocks/tapbundle';
+import { startTestServer, stopTestServer } from '../server.loader.js';
+
+const TEST_PORT = 2525;
+const TEST_TIMEOUT = 10000;
+
+tap.test('prepare server', async () => {
+  await startTestServer();
+  await new Promise(resolve => setTimeout(resolve, 100));
+});
+
+tap.test('test name', async (tools) => {
+  const done = tools.defer();
+  // test implementation
+  done.resolve();
+});
+
+tap.test('cleanup server', async () => {
+  await stopTestServer();
+});
+
+tap.start();
+```
+
+### Common Issues and Solutions
+1. **Multi-line SMTP responses**: Handle response buffering carefully, especially for EHLO
+2. **Timing issues**: Use proper state management instead of string matching
+3. **ES Module imports**: Use `import` statements, not `require()`
+4. **Server cleanup**: Always close connections properly to avoid hanging tests
+5. **Response buffer management**: Clear the response buffer after processing each state to avoid false matches from previous responses. Use specific response patterns (e.g., '250 OK' instead of just '250') to avoid ambiguity.
+
+### SMTP Protocol Testing
+- Server generates self-signed certificates automatically for testing
+- Default test port is 2525
+- Connection timeout is typically 10 seconds
+- Always check for complete SMTP responses (ending with space after code)