@Test
public void validUnionInMap() throws SchemaValidationException {

  Schema union = SchemaBuilder.unionOf().intType().and().nullType().endUnion();
  Schema map = SchemaBuilder.map().values(union);
  Schema schema = SchemaBuilder.record("r").fields().name("f").type(map).noDefault().endRecord();
  DataHighwaySchemaValidator.validate(schema, DISALLOW_NON_NULLABLE_UNIONS);
}