Path policy REST API may return 500 (Internal Server Error) unexpectedly.

Path policy rest API returns 500 (Internal Server Error) response code
if PathCost element in the request body does not specify link cost.

PUT http://localhost:8080/controller/nb/v2/vtn/default/pathpolicies/1
{
"default": 10,
"cost": [
{
"location":

}
]
}

In this case VTN Manager should return 400 (Bad Request) as response code.