Merge d06bace into 10fb2ca

docs/source/usage.rst

@@ -193,6 +193,25 @@ Both stubs and mocks allow a method call to raise an exception instead of return
         else:
             raise AssertionError('Expected test to raise StandardError.')
 
+If the exception to be raised requires arguments, they can be passed to ``and_raises`` directly::
+
+    from doubles import allow
+
+    from myapp import User
+
+
+    def test_raising_an_exception():
+        user = User('Carl')
+
+        allow(user).get_name.and_raise(NonStandardError, 'an argument', arg2='another arg')
+
+        try:
+            user.get_name()
+        except NonStandardError:
+            pass
+        else:
+            raise AssertionError('Expected test to raise NonStandardError.')
+
 Call counts
 -----------
 

doubles/allowance.py

@@ -62,13 +62,16 @@ def __init__(self, target, method_name, caller):
 
         self._return_value = lambda *args, **kwargs: None
 
-    def and_raise(self, exception):
+    def and_raise(self, exception, *args, **kwargs):
         """Causes the double to raise the provided exception when called.
 
+        If provided, additional arguments (positional and keyword) passed to
+        `and_raise` are used in the exception instantiation.
+
         :param Exception exception: The exception to raise.
         """
-        def proxy_exception(*args, **kwargs):
-            raise exception
+        def proxy_exception(*proxy_args, **proxy_kwargs):
+            raise exception(*args, **kwargs)
 
         self._return_value = proxy_exception
         return self

test/return_values_test.py

@@ -9,6 +9,11 @@ class UserDefinedException(Exception):
     pass
 
 
+class UserDefinedExceptionWithArgs(Exception):
+    def __init__(self, msg, arg1, arg2=None):
+        pass
+
+
 @mark.parametrize('stubber', [allow, expect])
 class TestReturnValues(object):
     def test_returns_result_of_a_callable(self, stubber):
@@ -48,6 +53,15 @@ def test_raises_provided_exception(self, stubber):
         with raises(UserDefinedException):
             subject.instance_method()
 
+    def test_raises_provided_exception_with_complex_signature(self, stubber):
+        subject = InstanceDouble('doubles.testing.User')
+
+        stubber(subject).instance_method.and_raise(
+            UserDefinedExceptionWithArgs, 'msg', 'arg1', arg2='arg2')
+
+        with raises(UserDefinedExceptionWithArgs):
+            subject.instance_method()
+
     def test_chaining_result_methods_gives_the_last_one_precedence(self, stubber):
         subject = InstanceDouble('doubles.testing.User')