@Test
public void smallestNested() throws InvalidKeyPathException {

  Path path = KeyPathParser.parse("$[\"a\"]");
  Schema schema = SchemaBuilder
      .record("X")
      .fields()
      .name("a")
      .type(Schema.create(Type.STRING))
      .noDefault()
      .endRecord();
  new KeyPathValidator(path, schema).validate();
}