public function testRecursion()
{
$block1 = new DxfBlock();
$block2 = new DxfBlock();
$block3 = new DxfBlock();
$block4 = new DxfBlock();
$block1->add(10, 11);
$block1->add(4, "fff");
$block2->add(90, 9);
$block2->addBlock($block1);
$block3->addBlock($block1);
$block3->addBlock($block2);
$block4->add(5, "hello");
$block4->addBlock($block3);
$block4->addBlock($block2);
$block4->add(1, 1);
$block4->addBlock($block1);
$stringExpected = "5\r\nhello\r\n10\r\n11\r\n4\r\nfff\r\n90\r\n9\r\n10\r\n11\r\n" . "4\r\nfff\r\n90\r\n9\r\n10\r\n11\r\n4\r\nfff\r\n1\r\n1\r\n10\r\n11\r\n" . "4\r\nfff\r\n";
$this->assertEquals($stringExpected, $block4->toString());
}