public function testTreeOperations() { $newNode1 = new Tree\Node('abc', 'node1', $this->_tree); $this->_tree->addNode($newNode1); $newNode2 = new Tree\Node('def', 'node2', $this->_tree); $this->_tree->addNode($newNode2, $newNode1); $newNode3 = new Tree\Node('ghi', 'node3', $this->_tree); $this->_tree->addNode($newNode3, $newNode1); $data1 = ['j', 'k', 'l']; $this->_tree->appendChild($data1, $newNode3); $newNode4 = new Tree\Node('mno', 'node4', $this->_tree); $this->_tree->appendChild($newNode4, $newNode3); $this->_tree->removeNode($newNode4); $this->_tree->removeNode($newNode3); $this->_tree->removeNode($newNode2); $this->_tree->removeNode($newNode1); $this->assertEmpty($this->_tree->getNodes()->getNodes()); }