MyBinarySearchTree.java

public class MyBinarySearchTree {

  private MyTreeNode root;
  private int size;

  public MyBinarySearchTree() {
    this.root = null;
    size = 0;
  }

  public void add(Integer data) {

  }

  public void remove(Integer data) {

  }

  public boolean contains(Integer data) {
    return contains(root, data);
  }

  private boolean contains(MyTreeNode root, Integer data) {
    if (root == null) {
      return false;
    } else {
      if (root.getData() < data) {
        return contains(root.getLeft(), data);
      } else if(root.getData() > data)  {
        return contains(root.getRight(), data);
      } else {
        return true;
      }
    }
  }

  public int size() {
    return size;
  }

  private class MyTreeNode {
    private Integer data;
    private MyTreeNode left;
    private MyTreeNode right;
    private MyTreeNode parent;

    public MyTreeNode(Integer data) {
      this.data = data;
      this.left = null;
      this.right = null;
      this.parent = null;
    }

    public MyTreeNode(Integer data, MyTreeNode left, MyTreeNode right, MyTreeNode parent) {
      this.data = data;
      this.left = left;
      this.right = right;
      this.parent = parent;
    }

    public Integer getData() {
      return data;
    }

    public void setData(Integer data) {
      this.data = data;
    }

    public MyTreeNode getLeft() {
      return left;
    }

    public void setLeft(MyTreeNode left) {
      this.left = left;
    }

    public MyTreeNode getRight() {
      return right;
    }

    public void setRight(MyTreeNode right) {
      this.right = right;
    }

    public MyTreeNode getParent() {
      return parent;
    }

    public void setParent(MyTreeNode parent) {
      this.parent = parent;
    }

  }
}

MyBinarySearchTreeTest.java

import junit.framework.TestCase;
import org.junit.Test;


public class MyBinarySearchTreeTest extends TestCase {
   MyBinarySearchTree tree;

   @Override
   protected void setUp() throws Exception {
      tree = new MyBinarySearchTree();
   }

   @Test
   public void testAdd() throws Exception {
      tree.add(15);
      assertTrue(tree.contains(15));
   }

   @Test
   public void testRemove() throws Exception {
      tree.add(15);
      tree.add(20);
      tree.remove(15);
      assertFalse(tree.contains(15));
      assertTrue(tree.contains(20));
   }

   @Test
   public void testContains() throws Exception {
      tree.add(5);
      tree.add(10);
      tree.add(30);
      tree.add(5);
      tree.add(20);
      tree.add(40);
      assertEquals(true, tree.contains(5));
      assertEquals(false, tree.contains(16));
   }


}