Testing PipelineOptions builder syntax using self-referencing generics

GenericPipelineOptions.java

import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)
public class GenericPipelineOptions {

  public interface PipelineOptions<T extends PipelineOptions<T>> {}

  public interface OptionsA<T extends OptionsA<T>> extends PipelineOptions<T> {
    T setA1();
    T setA2();
  }

  public interface OptionsB<T extends OptionsB<T>> extends PipelineOptions<T> {
    T setB1();
    T setB2();
  }

  public interface OptionsAB<T extends OptionsA<T> & OptionsB<T>> extends OptionsA<T>, OptionsB<T> {}

  @Test
  public void testBuilderSyntax() {
    OptionsAB<?> opt = null;

    opt
        .setA1()
        .setA2()
        .setB1()
        .setB2();
  }
}