public function testGetRightTree()
{
$obj_binaryTree = new BinaryTree('content', new BinaryTree('content L'), new BinaryTree('content R'));
$this->assertEquals('content R', $obj_binaryTree->getRightTree()->getObject(), 'Right tree\'s content should equal content R.');
$obj_binaryTreeEmpty = new BinaryTree();
$this->assertNull($obj_binaryTreeEmpty->getRightTree(), 'Right tree should be null.');
}