The inspect.signature() method was only added in Python 3.3. #31

docs/changes.rst

@@ -1,6 +1,18 @@
 Release Notes
 =============
 
+Version 1.9.1
+-------------
+
+**Bugs Fixed**
+
+* The ``inspect.signature()`` function was only added in Python 3.3.
+  Use fallback when doesn't exist and on Python 3.2 or earlier Python 3
+  versions.
+  
+  Note that testing is only performed for Python 3.3+, so it isn't
+  actually known if the ``wrapt`` package works on Python 3.2.
+
 Version 1.9.0
 -------------
 

src/decorators.py

@@ -13,8 +13,10 @@ from inspect import getargspec, ismethod, isclass
 from collections import namedtuple
 from threading import Lock, RLock
 
-if not PY2:
+try:
     from inspect import signature
+except ImportError:
+    pass
 
 from .wrappers import (FunctionWrapper, BoundFunctionWrapper, ObjectProxy,
     CallableObjectProxy)
@@ -72,7 +74,7 @@ class _AdapterFunctionSurrogate(CallableObjectProxy):
 
     @property
     def __signature__(self):
-        if PY2:
+        if 'signature' not in globals():
             return self._self_adapter.__signature__
         else:
             # Can't allow this to fail on Python 3 else it falls

tests/conftest.py

@@ -1,13 +1,17 @@
 import pytest
 
-from compat import PY2, PY3
+import sys
+
+version = tuple(sys.version_info[:2])
 
 class DummyCollector(pytest.collect.File):
     def collect(self):
          return []
 
 def pytest_pycollect_makemodule(path, parent):
-    if "py3" in path.basename and not PY3:
+    if '_py33' in path.basename and version < (3, 3):
         return DummyCollector(path, parent=parent)
-    if "py2" in path.basename and not PY2:
+    if '_py3' in path.basename and version < (3, 0):
+        return DummyCollector(path, parent=parent)
+    if '_py2' in path.basename and version >= (3, 0):
         return DummyCollector(path, parent=parent)