fix(tests): Update test assertions and refine service interfaces

ts/platformservice.ts

@@ -35,4 +35,11 @@ export class SzPlatformService {
     });
     await this.typedserver.start();
   }
+  
+  public async stop() {
+    // Stop the server if it's running
+    if (this.typedserver) {
+      await this.typedserver.stop();
+    }
+  }
 }