fix: Fix bug when wrapping base values.

google/cloud/ndb/model.py

@@ -635,14 +635,16 @@ def new_entity(key):
 
                 continue
 
+        def base_value_or_none(value):
+            return None if value is None else _BaseValue(value)
+
         if not (prop is not None and isinstance(prop, Property)):
             if value is not None and isinstance(  # pragma: NO BRANCH
                 entity, Expando
             ):
                 if isinstance(value, list):
                     value = [
-                        (_BaseValue(sub_value) if sub_value else None)
-                        for sub_value in value
+                        base_value_or_none(sub_value) for sub_value in value
                     ]
                 else:
                     value = _BaseValue(value)
@@ -656,8 +658,7 @@ def new_entity(key):
                 if isinstance(value, list):
                     # Not a projection
                     value = [
-                        (_BaseValue(sub_value) if sub_value else None)
-                        for sub_value in value
+                        base_value_or_none(sub_value) for sub_value in value
                     ]
                 else:
                     # Projection

tests/system/test_crud.py

@@ -1095,3 +1095,21 @@ def user_id(self):
     retreived = key.get()
     assert retreived.user.email() == "somebody@example.com"
     assert retreived.user.auth_domain() == "gmail.com"
+
+
+@pytest.mark.usefixtures("client_context")
+def test_repeated_empty_strings(dispose_of):
+    """Regression test for issue # 300.
+
+    https://github.com/googleapis/python-ndb/issues/300
+    """
+
+    class SomeKind(ndb.Model):
+        foo = ndb.StringProperty(repeated=True)
+
+    entity = SomeKind(foo=["", ""])
+    key = entity.put()
+    dispose_of(key._key)
+
+    retreived = key.get()
+    assert retreived.foo == ["", ""]