Closes issue 14636. mock objects raise exceptions from an iterable side_effect

2 files changed, 17 insertions, 3 deletions

diff --git a/Lib/unittest/mock.py b/Lib/unittest/mock.py
index 8cedcb4..8378b0f 100644
--- a/Lib/unittest/mock.py
+++ b/Lib/unittest/mock.py
@@ -891,7 +891,10 @@ class CallableMixin(Base):
                 raise effect
 
             if not _callable(effect):
-                return next(effect)
+                result = next(effect)
+                if _is_exception(result):
+                    raise result
+                return result
 
             ret_val = effect(*args, **kwargs)
             if ret_val is DEFAULT:
@@ -931,8 +934,9 @@ class Mock(CallableMixin, NonCallableMock):
       arguments as the mock, and unless it returns `DEFAULT`, the return
       value of this function is used as the return value.
 
-      Alternatively `side_effect` can be an exception class or instance. In
-      this case the exception will be raised when the mock is called.
+      If `side_effect` is an iterable then each call to the mock will return
+      the next value from the iterable. If any of the members of the iterable
+      are exceptions they will be raised instead of returned.
 
       If `side_effect` is an iterable then each call to the mock will return
       the next value from the iterable.
diff --git a/Lib/unittest/test/testmock/testmock.py b/Lib/unittest/test/testmock/testmock.py
index ae9822e..64fd1a1 100644
--- a/Lib/unittest/test/testmock/testmock.py
+++ b/Lib/unittest/test/testmock/testmock.py
@@ -868,6 +868,16 @@ class MockTest(unittest.TestCase):
         self.assertRaises(StopIteration, mock)
 
 
+    def test_side_effect_iterator_exceptions(self):
+        for Klass in Mock, MagicMock:
+            iterable = (ValueError, 3, KeyError, 6)
+            m = Klass(side_effect=iterable)
+            self.assertRaises(ValueError, m)
+            self.assertEqual(m(), 3)
+            self.assertRaises(KeyError, m)
+            self.assertEqual(m(), 6)
+
+
     def test_side_effect_setting_iterator(self):
         mock = Mock()
         mock.side_effect = iter([1, 2, 3])