Twig_Environment::parse PHP Method

    public function parse(Twig_TokenStream $tokens)
    {
        return $this->getParser()->parse($tokens);
    }

 public function testEmptyConstant()
 {
     $stream = $this->environment->parse($this->environment->tokenize('{{ constant("ExtensionTest::SOME_EMPTY_VALUE") }}', 'index'));
     $node = $stream->getNode('body')->getNode(0);
     $this->assertEquals(Twig_Node_Print::class, get_class($node));
     $this->assertEquals(ExtensionTest::SOME_EMPTY_VALUE, $node->getNode('expr')->getAttribute('value'));
 }