import org.junit.*;
import org.junit.runner.RunWith;
import static org.junit.Assert.*;
import static org.junit.Assume.*;

import org.junit.experimental.theories.DataPoint;
import org.junit.experimental.theories.DataPoints;
import org.junit.experimental.theories.Theories;
import org.junit.experimental.theories.Theory;

import java.util.*;

@RunWith(Theories.class)
public class SetTheoryTest {

   @DataPoints
   public static String[] string = {"ant", "bat", "cat"};

   @DataPoints
   public static Set[] sets = {
      new HashSet(Arrays.asList("ant", "bat")),
      new HashSet(Arrays.asList("bat", "cat", "dog", "elk")),
      new HashSet(Arrays.asList("Snap", "Crackle", "Pop"))
   };


   @Theory public <E> void removeThenAddDoesNotChangeSet(
         Set<E> set, E string) {             // Parameters!
      assumeTrue(set.contains(string));                // Assume
      Set<E> copy = new HashSet<E>(set);     // Act
      copy.remove(string);                       
      copy.add(string);
System.out.println("Set, string: " + set + ", " + string);
      assertTrue (set.equals(copy));                   // Assert
    }

}