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.'); }