public function testNonModifying()
{
$str1Node = new String_('Foo');
$str2Node = new String_('Bar');
$echoNode = new Node\Stmt\Echo_(array($str1Node, $str2Node));
$stmts = array($echoNode);
$visitor = $this->getMockBuilder('PhpParser\\NodeVisitor')->getMock();
$visitor->expects($this->at(0))->method('beforeTraverse')->with($stmts);
$visitor->expects($this->at(1))->method('enterNode')->with($echoNode);
$visitor->expects($this->at(2))->method('enterNode')->with($str1Node);
$visitor->expects($this->at(3))->method('leaveNode')->with($str1Node);
$visitor->expects($this->at(4))->method('enterNode')->with($str2Node);
$visitor->expects($this->at(5))->method('leaveNode')->with($str2Node);
$visitor->expects($this->at(6))->method('leaveNode')->with($echoNode);
$visitor->expects($this->at(7))->method('afterTraverse')->with($stmts);
$traverser = new NodeTraverser();
$traverser->addVisitor($visitor);
$this->assertEquals($stmts, $traverser->traverse($stmts));
}