PhpParser\NodeTraverserTest::testModifying PHP Method

    public function testModifying()
    {
        $str1Node = new String_('Foo');
        $str2Node = new String_('Bar');
        $printNode = new Expr\Print_($str1Node);
        // first visitor changes the node, second verifies the change
        $visitor1 = $this->getMockBuilder('PhpParser\\NodeVisitor')->getMock();
        $visitor2 = $this->getMockBuilder('PhpParser\\NodeVisitor')->getMock();
        // replace empty statements with string1 node
        $visitor1->expects($this->at(0))->method('beforeTraverse')->with(array())->will($this->returnValue(array($str1Node)));
        $visitor2->expects($this->at(0))->method('beforeTraverse')->with(array($str1Node));
        // replace string1 node with print node
        $visitor1->expects($this->at(1))->method('enterNode')->with($str1Node)->will($this->returnValue($printNode));
        $visitor2->expects($this->at(1))->method('enterNode')->with($printNode);
        // replace string1 node with string2 node
        $visitor1->expects($this->at(2))->method('enterNode')->with($str1Node)->will($this->returnValue($str2Node));
        $visitor2->expects($this->at(2))->method('enterNode')->with($str2Node);
        // replace string2 node with string1 node again
        $visitor1->expects($this->at(3))->method('leaveNode')->with($str2Node)->will($this->returnValue($str1Node));
        $visitor2->expects($this->at(3))->method('leaveNode')->with($str1Node);
        // replace print node with string1 node again
        $visitor1->expects($this->at(4))->method('leaveNode')->with($printNode)->will($this->returnValue($str1Node));
        $visitor2->expects($this->at(4))->method('leaveNode')->with($str1Node);
        // replace string1 node with empty statements again
        $visitor1->expects($this->at(5))->method('afterTraverse')->with(array($str1Node))->will($this->returnValue(array()));
        $visitor2->expects($this->at(5))->method('afterTraverse')->with(array());
        $traverser = new NodeTraverser();
        $traverser->addVisitor($visitor1);
        $traverser->addVisitor($visitor2);
        // as all operations are reversed we end where we start
        $this->assertEquals(array(), $traverser->traverse(array()));
    }