Add tests for logic in Entity.__repr__.

Fixes #174.

Author: tseaver

gcloud/datastore/entity.py

@@ -20,7 +20,7 @@
 
 
 class NoKey(RuntimeError):
-    pass
+    """Exception raised by Entity methods which require a key."""
 
 
 class Entity(dict):  # pylint: disable=too-many-public-methods
@@ -238,7 +238,6 @@ def delete(self):
             dataset_id=dataset.id(), key_pb=key.to_protobuf())
 
     def __repr__(self):
-        # An entity should have a key all the time (even if it's partial).
         if self._key:
             return '<Entity%s %s>' % (self._key.path(),
                                       super(Entity, self).__repr__())

gcloud/datastore/test_entity.py

@@ -88,7 +88,6 @@ def test_from_protobuf(self):
     def test_reload_no_key(self):
         from gcloud.datastore.entity import NoKey
 
-        dataset = _Dataset()
         entity = self._makeOne(None, None)
         entity['foo'] = 'Foo'
         self.assertRaises(NoKey, entity.reload)
@@ -116,7 +115,6 @@ def test_reload_hit(self):
     def test_save_no_key(self):
         from gcloud.datastore.entity import NoKey
 
-        dataset = _Dataset()
         entity = self._makeOne(None, None)
         entity['foo'] = 'Foo'
         self.assertRaises(NoKey, entity.save)
@@ -186,7 +184,6 @@ def test_save_w_returned_key(self):
     def test_delete_no_key(self):
         from gcloud.datastore.entity import NoKey
 
-        dataset = _Dataset()
         entity = self._makeOne(None, None)
         entity['foo'] = 'Foo'
         self.assertRaises(NoKey, entity.delete)
@@ -201,8 +198,23 @@ def test_delete(self):
         self.assertTrue(entity.delete() is None)
         self.assertEqual(connection._deleted, (_DATASET_ID, 'KEY'))
 
+    def test___repr___no_key_empty(self):
+        entity = self._makeOne(None, None)
+        self.assertEqual(repr(entity), '<Entity {}>')
+
+    def test___repr___w_key_non_empty(self):
+        connection = _Connection()
+        dataset = _Dataset(connection)
+        key = _Key(dataset)
+        key.path('/bar/baz')
+        entity = self._makeOne()
+        entity.key(key)
+        entity['foo'] = 'Foo'
+        self.assertEqual(repr(entity), "<Entity/bar/baz {'foo': 'Foo'}>")
+
 
 class _Key(object):
+    _MARKER = object()
     _key = 'KEY'
     _partial = False
     _path = None
@@ -219,7 +231,9 @@ def to_protobuf(self):
     def is_partial(self):
         return self._partial
 
-    def path(self, path):
+    def path(self, path=_MARKER):
+        if path is self._MARKER:
+            return self._path
         self._path = path