Add E2E tests, fix bugs

Made-with: Cursor

api_client.pyx

@@ -41,6 +41,8 @@ cdef class ApiClient:
         self.cdn_manager = CDNManager(creds)
 
     cdef login(self):
+        if self.credentials is None:
+            raise Exception("No credentials set")
         response = None
         try:
             response = requests.post(f"{self.api_url}/login",
@@ -112,6 +114,8 @@ cdef class ApiClient:
         response = self.request('post', f'{self.api_url}/resources/check', payload, is_stream=False)
 
     cdef load_bytes(self, str filename, str folder):
+        if self.credentials is None:
+            raise Exception("No credentials set")
         cdef str hardware = HardwareService.get_hardware_info()
         hw_hash = Security.get_hw_hash(hardware)
         key = Security.get_api_encryption_key(self.credentials, hw_hash)