factor out and test is_new_style

thomasballinger · thomasballinger · commit 6b7f681b065a · 2015-12-25T12:10:51.000-08:00
diff --git a/bpython/inspection.py b/bpython/inspection.py
@@ -69,7 +69,7 @@ def __enter__(self):
         # original methods. :-(
         # The upshot being that introspecting on an object to display its
         # attributes will avoid unwanted side-effects.
-        if py3 or type_ != types.InstanceType:
+        if is_new_style(self.obj):
             __getattr__ = getattr(type_, '__getattr__', None)
             if __getattr__ is not None:
                 try:
@@ -98,6 +98,15 @@ def __exit__(self, exc_type, exc_val, exc_tb):
         # /Dark magic
 
 
+if py3:
+    def is_new_style(obj):
+        return True
+else:
+    def is_new_style(obj):
+        """Returns True if obj is a new-style class or object"""
+        return type(obj) != types.InstanceType
+
+
 class _Repr(object):
     """
     Helper for `fixlongargs()`: Returns the given value in `__repr__()`.
diff --git a/bpython/test/test_inspection.py b/bpython/test/test_inspection.py
@@ -2,6 +2,7 @@
 
 import os
 
+from bpython._py3compat import py3
 from bpython import inspection
 from bpython.test import unittest
 from bpython.test.fodder import encoding_ascii
@@ -20,29 +21,35 @@
 '''
 
 
-class TestInspection(unittest.TestCase):
-    def test_is_callable(self):
-        class OldCallable:
-            def __call__(self):
-                pass
+class OldCallable:
+    def __call__(self):
+        pass
 
-        class Callable(object):
-            def __call__(self):
-                pass
 
-        class OldNoncallable:
-            pass
+class Callable(object):
+    def __call__(self):
+        pass
 
-        class Noncallable(object):
-            pass
 
-        def spam():
-            pass
+class OldNoncallable:
+    pass
+
+
+class Noncallable(object):
+    pass
 
-        class CallableMethod(object):
-            def method(self):
-                pass
 
+def spam():
+    pass
+
+
+class CallableMethod(object):
+    def method(self):
+        pass
+
+
+class TestInspection(unittest.TestCase):
+    def test_is_callable(self):
         self.assertTrue(inspection.is_callable(spam))
         self.assertTrue(inspection.is_callable(Callable))
         self.assertTrue(inspection.is_callable(Callable()))
@@ -53,6 +60,25 @@ def method(self):
         self.assertFalse(inspection.is_callable(None))
         self.assertTrue(inspection.is_callable(CallableMethod().method))
 
+    @unittest.skipIf(py3, 'old-style classes only exist in Python 2')
+    def test_is_new_style_py2(self):
+        self.assertTrue(inspection.is_new_style(spam))
+        self.assertTrue(inspection.is_new_style(Noncallable))
+        self.assertFalse(inspection.is_new_style(OldNoncallable))
+        self.assertTrue(inspection.is_new_style(Noncallable()))
+        self.assertFalse(inspection.is_new_style(OldNoncallable()))
+        self.assertTrue(inspection.is_new_style(None))
+
+    @unittest.skipUnless(py3, 'only in Python 3 are all classes new-style')
+    def test_is_new_style_py3(self):
+        self.assertTrue(inspection.is_new_style(spam))
+        self.assertTrue(inspection.is_new_style(Noncallable))
+        self.assertTrue(inspection.is_new_style(OldNoncallable))
+        self.assertTrue(inspection.is_new_style(Noncallable()))
+        self.assertTrue(inspection.is_new_style(OldNoncallable()))
+        self.assertTrue(inspection.is_new_style(None))
+
+
     def test_parsekeywordpairs(self):
         # See issue #109
         def fails(spam=['-a', '-b']):
