Merge pull request #231 from getsentry/issue-230

fix(py3) Fix syntax error when generating wrappers

Author: markstory

responses.py

@@ -128,25 +128,39 @@ def wrapper%(wrapper_args)s:
 
 
 def get_wrapped(func, responses):
-    # Preserve the argspec for the wrapped function so that testing
-    # tools such as pytest can continue to use their fixture injection.
-    is_bound_method = hasattr(func, "__self__")
-
     if six.PY2:
         args, a, kw, defaults = inspect.getargspec(func)
         wrapper_args = inspect.formatargspec(args, a, kw, defaults)
-        if is_bound_method:
+
+        # Preserve the argspec for the wrapped function so that testing
+        # tools such as pytest can continue to use their fixture injection.
+        if hasattr(func, "__self__"):
             args = args[1:]  # Omit 'self'
         func_args = inspect.formatargspec(args, a, kw, None)
     else:
         signature = inspect.signature(func)
-        wrapper_args = str(signature)
-        if is_bound_method:
-            new_params = list(signature.parameters.values())[1:]  # omit 'self'
-            signature = signature.replace(parameters=new_params)
+        signature = signature.replace(return_annotation=inspect.Signature.empty)
+        # If the function is wrapped, switch to *args, **kwargs for the parameters
+        # as we can't rely on the signature to give us the arguments the function will
+        # be called with. For example unittest.mock.patch uses required args that are
+        # not actually passed to the function when invoked.
+        if hasattr(func, "__wrapped__"):
+            wrapper_params = [
+                inspect.Parameter("args", inspect.Parameter.VAR_POSITIONAL),
+                inspect.Parameter("kwargs", inspect.Parameter.VAR_KEYWORD),
+            ]
+        else:
+            wrapper_params = [
+                param.replace(annotation=inspect.Parameter.empty)
+                for param in signature.parameters.values()
+            ]
+        signature = signature.replace(parameters=wrapper_params)
 
+        wrapper_args = str(signature)
         params_without_defaults = [
-            param.replace(default=inspect.Parameter.empty)
+            param.replace(
+                annotation=inspect.Parameter.empty, default=inspect.Parameter.empty
+            )
             for param in signature.parameters.values()
         ]
         signature = signature.replace(parameters=params_without_defaults)
@@ -158,10 +172,7 @@ def get_wrapped(func, responses):
         evaldict,
     )
     wrapper = evaldict["wrapper"]
-
     update_wrapper(wrapper, func)
-    if is_bound_method:
-        wrapper = wrapper.__get__(func.__self__, type(func.__self__))
     return wrapper
 
 

test_responses.py

@@ -4,13 +4,19 @@
 
 import inspect
 import re
+import six
 
 import pytest
 import requests
-from requests.exceptions import ConnectionError, HTTPError
 import responses
+from requests.exceptions import ConnectionError, HTTPError
 from responses import BaseResponse, Response
 
+try:
+    from mock import patch, Mock
+except ImportError:
+    from unittest.mock import patch, Mock
+
 
 def assert_reset():
     assert len(responses._default_mock._matches) == 0
@@ -524,6 +530,51 @@ def test_function(a, b=None):
     assert decorated_test_function(3) == test_function(3)
 
 
+def test_activate_mock_interaction():
+    @patch("sys.stdout")
+    def test_function(mock_stdout):
+        return mock_stdout
+
+    decorated_test_function = responses.activate(test_function)
+    if hasattr(inspect, "signature"):
+        assert inspect.signature(test_function) == inspect.signature(
+            decorated_test_function
+        )
+    else:
+        assert inspect.getargspec(test_function) == inspect.getargspec(
+            decorated_test_function
+        )
+
+    value = test_function()
+    assert isinstance(value, Mock)
+
+    value = decorated_test_function()
+    assert isinstance(value, Mock)
+
+
+@pytest.mark.skipif(six.PY2, reason="Cannot run in python2")
+def test_activate_doesnt_change_signature_with_return_type():
+    def test_function(a, b=None):
+        return (a, b)
+
+    # Add type annotations as they are syntax errors in py2.
+    # Use a class to test for import errors in evaled code.
+    test_function.__annotations__["return"] = Mock
+    test_function.__annotations__["a"] = Mock
+
+    decorated_test_function = responses.activate(test_function)
+    if hasattr(inspect, "signature"):
+        assert inspect.signature(test_function) == inspect.signature(
+            decorated_test_function
+        )
+    else:
+        assert inspect.getargspec(test_function) == inspect.getargspec(
+            decorated_test_function
+        )
+    assert decorated_test_function(1, 2) == test_function(1, 2)
+    assert decorated_test_function(3) == test_function(3)
+
+
 def test_activate_doesnt_change_signature_for_method():
     class TestCase(object):
         def test_function(self, a, b=None):