Make special __dunder__ methods work with CoClass (#1699)

CHANGES.txt

@@ -8,6 +8,9 @@ Note that build 228 was the last version supporting Python 2.
 
 Since build 300:
 ----------------
+* CoClass objects should work better with special methods like __len__ etc.
+  (#1699)
+
 * Creating a `win32crypt.CRYPT_ATTRIBUTE` object now correctly sets `cbData`.
 
 * COM objects are now registered with the full path to pythoncomXX.dll, fixes

com/win32com/client/__init__.py

@@ -534,6 +534,23 @@ def __setattr__(self, attr, value):
 			pass
 		self.__dict__[attr] = value
 
+  # Special methods don't use __getattr__ etc, so explicitly delegate here.
+  # Some wrapped objects might not have them, but that's OK - the attribute
+  # error can just bubble up.
+	def __call__(self, *args, **kwargs):
+		return self.__dict__["_dispobj_"].__call__(*args, **kwargs)
+	def __str__(self, *args):
+		return self.__dict__["_dispobj_"].__str__(*args)
+	def __int__(self, *args):
+		return self.__dict__["_dispobj_"].__int__(*args)
+	def __iter__(self):
+		return self.__dict__["_dispobj_"].__iter__()
+	def __len__(self):
+		return self.__dict__["_dispobj_"].__len__()
+	def __nonzero__(self):
+		return self.__dict__["_dispobj_"].__nonzero__()
+
+
 # A very simple VARIANT class.  Only to be used with poorly-implemented COM
 # objects.  If an object accepts an arg which is a simple "VARIANT", but still
 # is very pickly about the actual variant type (eg, isn't happy with a VT_I4,

com/win32com/client/genpy.py

@@ -607,7 +607,7 @@ def WriteClass(self, generator):
     for item, flag in self.interfaces:
       if flag & pythoncom.IMPLTYPEFLAG_FDEFAULT: # and dual:
         defItem = item
-      # If we have written a class, refeence its name, otherwise the IID
+      # If we have written a class, reference its name, otherwise the IID
       if item.bWritten: key = item.python_name
       else: key = repr(str(item.clsid)) # really the iid.
       print('\t\t%s,' % (key,), file=stream)

com/win32com/test/testPyComTest.py

@@ -172,10 +172,17 @@ def TestCommon(o, is_generated):
     progress("Checking getting/passing IUnknown")
     check_get_set(o.GetSetUnknown, o)
     progress("Checking getting/passing IDispatch")
-    if not isinstance(o.GetSetDispatch(o), o.__class__):
+    # This might be called with either the interface or the CoClass - but these
+    # functions always return from the interface.
+    expected_class = o.__class__
+    # CoClass instances have `default_interface`
+    expected_class = getattr(expected_class, "default_interface", expected_class)
+    if not isinstance(o.GetSetDispatch(o), expected_class):
         raise error("GetSetDispatch failed: %r" % (o.GetSetDispatch(o),))
     progress("Checking getting/passing IDispatch of known type")
-    if o.GetSetInterface(o).__class__ != o.__class__:
+    expected_class = o.__class__
+    expected_class = getattr(expected_class, "default_interface", expected_class)
+    if o.GetSetInterface(o).__class__ != expected_class:
         raise error("GetSetDispatch failed")
 
     progress("Checking misc args")
@@ -408,6 +415,16 @@ def TestGenerated():
     counter = EnsureDispatch("PyCOMTest.SimpleCounter")
     TestCounter(counter, True)
 
+    # This dance lets us get a CoClass even though it's not explicitly registered.
+    # This is `CoPyComTest`
+    from win32com.client.CLSIDToClass import GetClass
+    coclass_o = GetClass("{8EE0C520-5605-11D0-AE5F-CADD4C000000}")()
+    TestCommon(coclass_o, True)
+
+    # This is `CoSimpleCounter` and the counter tests should work.
+    coclass = GetClass("{B88DD310-BAE8-11D0-AE86-76F2C1000000}")()
+    TestCounter(coclass, True)
+
     # XXX - this is failing in dynamic tests, but should work fine.
     i1, i2 = o.GetMultipleInterfaces()
     if not isinstance(i1, DispatchBaseClass) or not isinstance(i2, DispatchBaseClass):