'Test regex matching on nodes.'

def test_node_regex(self):

    tree = ParentedTree.fromstring(u'(S    (NP-SBJ    x)    (NP    x)    (NNP    x)    (VP    x))')
    self.assertEqual(list(tgrep.tgrep_positions(u'/^NP/', [tree])), [[(0,), (1,)]])
