'Ensure that the _transform_query function operates correctly.'

def test_transform_query(self):

    self.assertEqual(transform.query(name='test', age=30), {'name': 'test', 'age': 30})
    self.assertEqual(transform.query(age__lt=30), {'age': {'$lt': 30}})
    self.assertEqual(transform.query(age__gt=20, age__lt=50), {'age': {'$gt': 20, '$lt': 50}})
    self.assertEqual(transform.query(age=20, age__gt=50), {'$and': [{'age': {'$gt': 50}}, {'age': 20}]})
    self.assertEqual(transform.query(friend__age__gte=30), {'friend.age': {'$gte': 30}})
    self.assertEqual(transform.query(name__exists=True), {'name': {'$exists': True}})
