IsSymmetricTest.java

import org.junit.Test;

import static org.junit.Assert.*;

public class IsSymmetricTest {

    private boolean expected;
    private BinaryTree<Integer> tree;

    @Test
    public void isSymmetric1() throws Exception {
        expected = true;
        tree = BinaryTreeUtil.getEvenTree();

        test(expected, tree);
    }

    @Test
    public void isSymmetric2() throws Exception {
        expected = false;
        tree = BinaryTreeUtil.getFigureTenDotOne();

        test(expected, tree);
    }

    @Test
    public void isSymmetric3() throws Exception {
        expected = true;
        tree = new BinaryTree<>(0);
        tree.right = new BinaryTree<>(1);
        tree.right.left = new BinaryTree<>(2);
        tree.left = new BinaryTree<>(1);
        tree.left.right = new BinaryTree<>(2);

        test(expected, tree);
    }

    @Test
    public void isSymmetric4() throws Exception {
        expected = false;
        tree = new BinaryTree<>(0);
        tree.right = new BinaryTree<>(1);
        tree.right.left = new BinaryTree<>(17);
        tree.left = new BinaryTree<>(1);
        tree.left.right = new BinaryTree<>(42);

        test(expected, tree);
    }

    private void test(boolean expected, BinaryTree<Integer> tree) {
        assertEquals(expected, IsSymmetric.isSymmetric(tree));
    }

}