tests/qapi-schema/union-unknown.json

# we reject a union with unknown type in branch
{ 'enum': 'Enum', 'data': [ 'unknown' ] }
{ 'union': 'Union',
  'base': { 'type': 'Enum' },
  'discriminator': 'type',
  'data': { 'unknown': 'MissingType' } }