Merge pull request #185 from tseaver/134-key-from_path-contract

Fix #134:  document / enforce Key.from_path contract

gcloud/datastore/key.py

@@ -125,6 +125,9 @@ def from_path(cls, *args, **kwargs):
  :rtype: :class:`gcloud.datastore.key.Key`
  :returns: a new `Key` instance
  """
+ if len(args) % 2:
+ raise ValueError('Must pass an even number of args.')
+
  path = []
  items = iter(args)
 

gcloud/datastore/test_key.py

@@ -172,12 +172,11 @@ def test_from_path_empty(self):
  self.assertEqual(key.path(), [{'kind': ''}])
 
  def test_from_path_single_element(self):
- # See https://github.com/GoogleCloudPlatform/gcloud-python/issues/134
- key = self._getTargetClass().from_path('abc')
- self.assertEqual(key.dataset(), None)
- self.assertEqual(key.namespace(), None)
- self.assertEqual(key.kind(), '') # XXX s.b. 'abc'?
- self.assertEqual(key.path(), [{'kind': ''}]) # XXX s.b. 'abc'?
+ self.assertRaises(ValueError, self._getTargetClass().from_path, 'abc')
+
+ def test_from_path_three_elements(self):
+ self.assertRaises(ValueError, self._getTargetClass().from_path,
+ 'abc', 'def', 'ghi')
 
  def test_from_path_two_elements_second_string(self):
  key = self._getTargetClass().from_path('abc', 'def')