public class HaHa {
  public void sayHaHa() {
    System.out.println("HaHa");
  }
 
  public String sayBye() {
    System.out.println("Bye");
    return "Byt";
  }
}

import org.junit.Assert;
import org.junit.Test;
 
import static org.junit.Assert.*;
 
public class HaHaTest {
 
  @Test
  public void sayHaHa() {
    new HaHa().sayHaHa();
  }
 
  @Test
  public void sayBye() {
    String bye = new HaHa().sayBye();
    Assert.assertEquals("Byt", bye);
  }
}