import org.jmock.Expectations;
import org.jmock.Mockery;
import org.jmock.integration.junit4.JMock;
import org.jmock.integration.junit4.JUnit4Mockery;
import org.jmock.lib.legacy.ClassImposteriser;
import org.junit.Test;
import org.junit.runner.RunWith;

import java.util.Comparator;

@RunWith(JMock.class)
public class ComparatorTest {
  @SuppressWarnings({ "EmptyClass" })
  private Mockery context = new JUnit4Mockery() {{
      setImposteriser(ClassImposteriser.INSTANCE);
  }};

  @Test
  public void failingTest() throws Exception {
    final MyComparator comparator = context.mock(MyComparator.class);
    final MyComparable a = new MyComparable();
    final MyComparable b = new MyComparable();

    context.checking(new Expectations() {{
      one(comparator).compare(a, b); will(returnValue(0));
    }});

    compare(a, b, comparator);
  }

  @Test
  public void passingTest() throws Exception {
    final Comparator comparator = context.mock(MyComparator.class);
    final MyComparable a = new MyComparable();
    final MyComparable b = new MyComparable();

    context.checking(new Expectations() {{
      one(comparator).compare(a, b); will(returnValue(0));
    }});

    compare(a, b, comparator);
  }

  private <T> int compare(T a, T b, Comparator<T> c) {
    return c.compare(a, b);
  }

  static class MyComparable implements Comparable {
    public int compareTo(Object o) {
      return 0;
    }
  }

  static class MyComparator implements Comparator<MyComparable> {
    public int compare(MyComparable o1, MyComparable o2) {
      return 0;
    }
  }
}