Record exceptions as side effects for spies

Author: inderpreet99

src/pytest_mock/plugin.py

@@ -116,7 +116,7 @@ def wrapper(*args, **kwargs):
             try:
                 r = method(*args, **kwargs)
             except Exception as e:
-                result.return_value = e
+                result.side_effect = e
                 raise
             else:
                 result.return_value = r

tests/test_pytest_mock.py

@@ -259,7 +259,7 @@ def bar(self, arg):
     assert str(exc_info.value) == excepted_message
 
     foo.bar.assert_called_once_with(arg=10)
-    assert spy.return_value == exc_info.value
+    assert spy.side_effect == exc_info.value
 
 
 @skip_pypy