correctly handle failure cases and support three-argument getattr

CHANGES.rst

@@ -4,7 +4,7 @@ Changelog
 3.0 (unreleased)
 ----------------
 
-- Add support for `__contains__`.
+- Add support for `__contains__` and default argument to `getattr`.
 
 - Rewrite tests as unit tests.
 

src/Record/__init__.py

@@ -58,12 +58,14 @@ def __getitem__(self, key):
                 raise TypeError('invalid record schema')
         return self._data[pos]
 
-    def __getattr__(self, key):
+    def __getattr__(self, key, default=_marker):
         if key in self.__slots__:
             return object.__getattribute__(self, key)
         try:
             return self.__getitem__(key)
         except KeyError:
+            if default is not _marker:
+                return default
             raise AttributeError(key)
 
     def __setitem__(self, key, value):
@@ -81,7 +83,10 @@ def __setattr__(self, key, value):
         if key in self.__slots__:
             object.__setattr__(self, key, value)
         else:
-            self.__setitem__(key, value)
+            try:
+                self.__setitem__(key, value)
+            except KeyError:
+                raise AttributeError(key)
 
     def __contains__(self, key):
         return key in self._schema

src/Record/tests.py

@@ -84,6 +84,9 @@ def test_attribute(self):
         self.assertTrue(r.c is None)
         r.a = 1
         self.assertEqual(r.a, 1)
+        self.assertEqual(getattr(r, 'd', 2), 2)
+        self.assertRaises(AttributeError, getattr, r, 'd')
+        self.assertRaises(AttributeError, setattr, r, 'd', 2)
 
     def test_mapping(self):
         r = R()
@@ -93,6 +96,8 @@ def test_mapping(self):
         r['b'] = 42
         self.assertEqual(r['b'], 42)
         self.assertEqual(r.b, 42)
+        self.assertRaises(KeyError, r.__getitem__, 'd')
+        self.assertRaises(KeyError, r.__setitem__, 'd', 2)
 
     def test_sequence(self):
         r = R()