diff --git a/src/if_py_both.h b/src/if_py_both.h
index 706794c..8f60550 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -1611,7 +1611,7 @@
 
     ret = (rObj == Py_True);
 
-    Py_DECREF(Py_True);
+    Py_DECREF(rObj);
 
     return ret;
 }
@@ -1910,7 +1910,7 @@
 		    PyErr_FORMAT(PyExc_ValueError,
 			    N_("expected sequence element of size 2, "
 			    "but got sequence of size %d"),
-			    PySequence_Fast_GET_SIZE(fast));
+			    (int) PySequence_Fast_GET_SIZE(fast));
 		    return NULL;
 		}
 
@@ -2435,6 +2435,10 @@
 	clear_tv(&v);
     }
     Py_DECREF(iterator);
+
+    if (PyErr_Occurred())
+	return -1;
+
     return 0;
 }
 
@@ -3361,7 +3365,7 @@
 	long	height;
 	win_T	*savewin;
 
-	if (NumberToLong(valObject, &height, NUMBER_INT))
+	if (NumberToLong(valObject, &height, NUMBER_INT|NUMBER_UNSIGNED))
 	    return -1;
 
 #ifdef FEAT_GUI
@@ -3384,7 +3388,7 @@
 	long	width;
 	win_T	*savewin;
 
-	if (NumberToLong(valObject, &width, NUMBER_INT))
+	if (NumberToLong(valObject, &width, NUMBER_INT|NUMBER_UNSIGNED))
 	    return -1;
 
 #ifdef FEAT_GUI
@@ -3518,7 +3522,7 @@
     char	*str;
     char	*save;
     PyObject	*bytes = NULL;
-    Py_ssize_t	len;
+    Py_ssize_t	len = 0;
     PyInt	i;
     char	*p;
 
@@ -5483,6 +5487,7 @@
 #endif
     else if (PyObject_HasAttrString(obj, "keys"))
 	return convert_dl(obj, tv, pymap_to_tv, lookup_dict);
+    /* PyObject_GetIter can create built-in iterator for any sequence object */
     else if (PyIter_Check(obj) || PySequence_Check(obj))
 	return convert_dl(obj, tv, pyseq_to_tv, lookup_dict);
     else if (PyMapping_Check(obj))
@@ -5930,11 +5935,8 @@
     {"_Loader",    (PyObject *)&LoaderType},
 };
 
-typedef int (*object_adder)(PyObject *, const char *, PyObject *);
-typedef PyObject *(*attr_getter)(PyObject *, const char *);
-
 #define ADD_OBJECT(m, name, obj) \
-    if (add_object(m, name, obj)) \
+    if (PyModule_AddObject(m, name, obj)) \
 	return -1;
 
 #define ADD_CHECKED_OBJECT(m, name, obj) \
@@ -5946,7 +5948,7 @@
     }
 
     static int
-populate_module(PyObject *m, object_adder add_object, attr_getter get_attr)
+populate_module(PyObject *m)
 {
     int		i;
     PyObject	*other_module;
@@ -5990,7 +5992,7 @@
     if (!(py_chdir = PyObject_GetAttrString(other_module, "chdir")))
 	return -1;
     ADD_OBJECT(m, "_chdir", py_chdir);
-    if (!(attr = get_attr(m, "chdir")))
+    if (!(attr = PyObject_GetAttrString(m, "chdir")))
 	return -1;
     if (PyObject_SetAttrString(other_module, "chdir", attr))
     {
@@ -6002,7 +6004,7 @@
     if ((py_fchdir = PyObject_GetAttrString(other_module, "fchdir")))
     {
 	ADD_OBJECT(m, "_fchdir", py_fchdir);
-	if (!(attr = get_attr(m, "fchdir")))
+	if (!(attr = PyObject_GetAttrString(m, "fchdir")))
 	    return -1;
 	if (PyObject_SetAttrString(other_module, "fchdir", attr))
 	{
diff --git a/src/if_python.c b/src/if_python.c
index da27838..d72dbfc 100644
--- a/src/if_python.c
+++ b/src/if_python.c
@@ -1404,8 +1404,7 @@
     vim_module = Py_InitModule4("vim", VimMethods, (char *)NULL,
 				(PyObject *)NULL, PYTHON_API_VERSION);
 
-    if (populate_module(vim_module, PyModule_AddObject,
-			   PyObject_GetAttrString))
+    if (populate_module(vim_module))
 	return -1;
 
     if (init_sys_path())
diff --git a/src/if_python3.c b/src/if_python3.c
index 3d9a5ee..badf015 100644
--- a/src/if_python3.c
+++ b/src/if_python3.c
@@ -1623,7 +1623,7 @@
     if ((vim_module = PyModule_Create(&vimmodule)) == NULL)
 	return NULL;
 
-    if (populate_module(vim_module, PyModule_AddObject, PyObject_GetAttrString))
+    if (populate_module(vim_module))
 	return NULL;
 
     if (init_sys_path())
diff --git a/src/testdir/pythonx/failing.py b/src/testdir/pythonx/failing.py
new file mode 100644
index 0000000..30e73a0
--- /dev/null
+++ b/src/testdir/pythonx/failing.py
@@ -0,0 +1 @@
+raise NotImplementedError
diff --git a/src/testdir/pythonx/failing_import.py b/src/testdir/pythonx/failing_import.py
new file mode 100644
index 0000000..511cae7
--- /dev/null
+++ b/src/testdir/pythonx/failing_import.py
@@ -0,0 +1 @@
+raise ImportError
diff --git a/src/testdir/pythonx/topmodule/__init__.py b/src/testdir/pythonx/topmodule/__init__.py
new file mode 100644
index 0000000..792d600
--- /dev/null
+++ b/src/testdir/pythonx/topmodule/__init__.py
@@ -0,0 +1 @@
+#
diff --git a/src/testdir/pythonx/topmodule/submodule/__init__.py b/src/testdir/pythonx/topmodule/submodule/__init__.py
new file mode 100644
index 0000000..792d600
--- /dev/null
+++ b/src/testdir/pythonx/topmodule/submodule/__init__.py
@@ -0,0 +1 @@
+#
diff --git a/src/testdir/pythonx/topmodule/submodule/subsubmodule/__init__.py b/src/testdir/pythonx/topmodule/submodule/subsubmodule/__init__.py
new file mode 100644
index 0000000..792d600
--- /dev/null
+++ b/src/testdir/pythonx/topmodule/submodule/subsubmodule/__init__.py
@@ -0,0 +1 @@
+#
diff --git a/src/testdir/pythonx/topmodule/submodule/subsubmodule/subsubsubmodule.py b/src/testdir/pythonx/topmodule/submodule/subsubmodule/subsubsubmodule.py
new file mode 100644
index 0000000..792d600
--- /dev/null
+++ b/src/testdir/pythonx/topmodule/submodule/subsubmodule/subsubsubmodule.py
@@ -0,0 +1 @@
+#
diff --git a/src/testdir/test86.in b/src/testdir/test86.in
index d8afc96..61b24ac 100644
--- a/src/testdir/test86.in
+++ b/src/testdir/test86.in
@@ -216,6 +216,7 @@
 :let messages=[]
 :delfunction DictNew
 py <<EOF
+import sys
 d=vim.bindeval('{}')
 m=vim.bindeval('messages')
 def em(expr, g=globals(), l=locals()):
@@ -297,7 +298,7 @@
 :" threading
 :let l = [0]
 :py l=vim.bindeval('l')
-:py <<EOF
+py <<EOF
 import threading
 import time
 
@@ -327,7 +328,7 @@
 :" settrace
 :let l = []
 :py l=vim.bindeval('l')
-:py <<EOF
+py <<EOF
 import sys
 
 def traceit(frame, event, arg):
@@ -342,9 +343,9 @@
 EOF
 :py sys.settrace(traceit)
 :py trace_main()
+:py sys.settrace(None)
 :py del traceit
 :py del trace_main
-:py sys.settrace(None)
 :$put =string(l)
 :"
 :" Slice
@@ -880,10 +881,16 @@
         if expr.find('None') > -1:
             msg = msg.replace('TypeError:(\'iteration over non-sequence\',)',
                               'TypeError:("\'NoneType\' object is not iterable",)')
+        if expr.find('FailingNumber') > -1:
+            msg = msg.replace(', not \'FailingNumber\'', '').replace('"', '\'')
+            msg = msg.replace('TypeError:(\'iteration over non-sequence\',)',
+                              'TypeError:("\'FailingNumber\' object is not iterable",)')
+        if msg.find('(\'\'') > -1 or msg.find('(\'can\'t') > -1:
+            msg = msg.replace('(\'', '("').replace('\',)', '",)')
         if expr == 'fd(self=[])':
             # HACK: PyMapping_Check changed meaning
             msg = msg.replace('AttributeError:(\'keys\',)',
-                              'TypeError:(\'unable to convert object to vim dictionary\',)')
+                              'TypeError:(\'unable to convert list to vim dictionary\',)')
         cb.append(expr + ':' + msg)
     else:
         cb.append(expr + ':NOT FAILED')
@@ -942,6 +949,7 @@
         '{u"": 1}',             # Same, but with unicode object
         'FailingMapping()',     #
         'FailingMappingKey()',  #
+        'FailingNumber()',      #
     ))
 
 def convertfrompymapping_test(expr):
@@ -956,66 +964,104 @@
         'FailingIterNext()',
     ))
 
+def number_test(expr, natural=False, unsigned=False):
+    if natural:
+        unsigned = True
+    return subexpr_test(expr, 'NumberToLong', (
+        '[]',
+        'None',
+    ) + (unsigned and ('-1',) or ())
+    + (natural and ('0',) or ()))
+
 class FailingTrue(object):
     def __nonzero__(self):
-        raise NotImplementedError
+        raise NotImplementedError('bool')
 
 class FailingIter(object):
     def __iter__(self):
-        raise NotImplementedError
+        raise NotImplementedError('iter')
 
 class FailingIterNext(object):
     def __iter__(self):
         return self
 
     def next(self):
-        raise NotImplementedError
+        raise NotImplementedError('next')
 
 class FailingMappingKey(object):
     def __getitem__(self, item):
-        raise NotImplementedError
+        raise NotImplementedError('getitem:mappingkey')
 
     def keys(self):
         return list("abcH")
 
 class FailingMapping(object):
     def __getitem__(self):
-        raise NotImplementedError
+        raise NotImplementedError('getitem:mapping')
 
     def keys(self):
-        raise NotImplementedError
+        raise NotImplementedError('keys')
 
 class FailingList(list):
     def __getitem__(self, idx):
         if i == 2:
-            raise NotImplementedError
+            raise NotImplementedError('getitem:list')
         else:
             return super(FailingList, self).__getitem__(idx)
 
+class NoArgsCall(object):
+    def __call__(self):
+        pass
+
+class FailingCall(object):
+    def __call__(self, path):
+        raise NotImplementedError('call')
+
+class FailingNumber(object):
+    def __int__(self):
+        raise NotImplementedError('int')
+
 cb.append("> Output")
 cb.append(">> OutputSetattr")
 ee('del sys.stdout.softspace')
-ee('sys.stdout.softspace = []')
+number_test('sys.stdout.softspace = %s', unsigned=True)
+number_test('sys.stderr.softspace = %s', unsigned=True)
 ee('sys.stdout.attr = None')
 cb.append(">> OutputWrite")
 ee('sys.stdout.write(None)')
 cb.append(">> OutputWriteLines")
 ee('sys.stdout.writelines(None)')
 ee('sys.stdout.writelines([1])')
-#iter_test('sys.stdout.writelines(%s)')
+iter_test('sys.stdout.writelines(%s)')
 cb.append("> VimCommand")
-ee('vim.command(1)')
+stringtochars_test('vim.command(%s)')
+ee('vim.command("", 2)')
 #! Not checked: vim->python exceptions translating: checked later
 cb.append("> VimToPython")
 #! Not checked: everything: needs errors in internal python functions
 cb.append("> VimEval")
-ee('vim.eval(1)')
+stringtochars_test('vim.eval(%s)')
+ee('vim.eval("", FailingTrue())')
 #! Not checked: everything: needs errors in internal python functions
 cb.append("> VimEvalPy")
-ee('vim.bindeval(1)')
+stringtochars_test('vim.bindeval(%s)')
+ee('vim.eval("", 2)')
 #! Not checked: vim->python exceptions translating: checked later
 cb.append("> VimStrwidth")
-ee('vim.strwidth(1)')
+stringtochars_test('vim.strwidth(%s)')
+cb.append("> VimForeachRTP")
+ee('vim.foreach_rtp(None)')
+ee('vim.foreach_rtp(NoArgsCall())')
+ee('vim.foreach_rtp(FailingCall())')
+ee('vim.foreach_rtp(int, 2)')
+cb.append('> import')
+old_rtp = vim.options['rtp']
+vim.options['rtp'] = os.getcwd().replace(',', '\\,').replace('\\', '\\\\')
+ee('import xxx_no_such_module_xxx')
+ee('import failing_import')
+ee('import failing')
+vim.options['rtp'] = old_rtp
+del old_rtp
 cb.append("> Dictionary")
 cb.append(">> DictionaryConstructor")
 ee('vim.Dictionary("abcI")')
@@ -1043,7 +1089,7 @@
 cb.append(">>> iter")
 ee('d.update(FailingMapping())')
 ee('d.update([FailingIterNext()])')
-#iter_test('d.update(%s)')
+iter_test('d.update(%s)')
 convertfrompyobject_test('d.update(%s)')
 stringtochars_test('d.update(((%s, 0),))')
 convertfrompyobject_test('d.update((("a", %s),))')
@@ -1055,7 +1101,7 @@
 cb.append(">> ListConstructor")
 ee('vim.List(1, 2)')
 ee('vim.List(a=1)')
-#iter_test('vim.List(%s)')
+iter_test('vim.List(%s)')
 convertfrompyobject_test('vim.List([%s])')
 cb.append(">> ListItem")
 ee('l[1000]')
@@ -1064,10 +1110,10 @@
 ee('l[1000] = 3')
 cb.append(">> ListAssSlice")
 ee('ll[1:100] = "abcJ"')
-#iter_test('l[:] = %s')
+iter_test('l[:] = %s')
 convertfrompyobject_test('l[:] = [%s]')
 cb.append(">> ListConcatInPlace")
-#iter_test('l.extend(%s)')
+iter_test('l.extend(%s)')
 convertfrompyobject_test('l.extend([%s])')
 cb.append(">> ListSetattr")
 ee('del l.locked')
@@ -1094,14 +1140,15 @@
 ee('vim.current.window.buffer = 0')
 ee('vim.current.window.cursor = (100000000, 100000000)')
 ee('vim.current.window.cursor = True')
-ee('vim.current.window.height = "abcK"')
-ee('vim.current.window.width  = "abcL"')
+number_test('vim.current.window.height = %s', unsigned=True)
+number_test('vim.current.window.width = %s', unsigned=True)
 ee('vim.current.window.xxxxxx = True')
 cb.append("> WinList")
 cb.append(">> WinListItem")
 ee('vim.windows[1000]')
 cb.append("> Buffer")
 cb.append(">> StringToLine (indirect)")
+ee('vim.current.buffer[0] = u"\\na"')
 ee('vim.current.buffer[0] = "\\na"')
 cb.append(">> SetBufferLine (indirect)")
 ee('vim.current.buffer[0] = True')
@@ -1129,8 +1176,8 @@
 ee('vim.current.buffer.range(1, 2, 3)')
 cb.append("> BufMap")
 cb.append(">> BufMapItem")
-ee('vim.buffers[None]')
 ee('vim.buffers[100000000]')
+number_test('vim.buffers[%s]', natural=True)
 cb.append("> Current")
 cb.append(">> CurrentGetattr")
 ee('vim.current.xxx')
@@ -1154,12 +1201,16 @@
 del convertfrompyobject_test
 del convertfrompymapping_test
 del iter_test
+del number_test
 del FailingTrue
 del FailingIter
 del FailingIterNext
 del FailingMapping
 del FailingMappingKey
 del FailingList
+del NoArgsCall
+del FailingCall
+del FailingNumber
 EOF
 :delfunction F
 :"
@@ -1168,6 +1219,16 @@
 sys.path.insert(0, os.path.join(os.getcwd(), 'python_before'))
 sys.path.append(os.path.join(os.getcwd(), 'python_after'))
 vim.options['rtp'] = os.getcwd().replace(',', '\\,').replace('\\', '\\\\')
+l = []
+def callback(path):
+    l.append(path[-len('/testdir'):])
+vim.foreach_rtp(callback)
+cb.append(repr(l))
+del l
+def callback(path):
+    return path[-len('/testdir'):]
+cb.append(repr(vim.foreach_rtp(callback)))
+del callback
 from module import dir as d
 from modulex import ddir
 cb.append(d + ',' + ddir)
@@ -1175,10 +1236,19 @@
 cb.append(before.dir)
 import after
 cb.append(after.dir)
+import topmodule as tm
+import topmodule.submodule as tms
+import topmodule.submodule.subsubmodule.subsubsubmodule as tmsss
+cb.append(tm.__file__.replace('.pyc', '.py')[-len('modulex/topmodule/__init__.py'):])
+cb.append(tms.__file__.replace('.pyc', '.py')[-len('modulex/topmodule/submodule/__init__.py'):])
+cb.append(tmsss.__file__.replace('.pyc', '.py')[-len('modulex/topmodule/submodule/subsubmodule/subsubsubmodule.py'):])
 del before
 del after
 del d
 del ddir
+del tm
+del tms
+del tmsss
 EOF
 :"
 :" Test exceptions
@@ -1232,6 +1302,7 @@
 :call garbagecollect(1)
 :"
 :/^start:/,$wq! test.out
+:" vim: et ts=4 isk-=\:
 :call getchar()
 ENDTEST
 
diff --git a/src/testdir/test86.ok b/src/testdir/test86.ok
index b4abcc2..6fdab0c 100644
--- a/src/testdir/test86.ok
+++ b/src/testdir/test86.ok
@@ -441,28 +441,69 @@
 > Output
 >> OutputSetattr
 del sys.stdout.softspace:AttributeError:("can't delete OutputObject attributes",)
+>>> Testing NumberToLong using sys.stdout.softspace = %s
 sys.stdout.softspace = []:TypeError:('expected int(), long() or something supporting coercing to long(), but got list',)
+sys.stdout.softspace = None:TypeError:('expected int(), long() or something supporting coercing to long(), but got NoneType',)
+sys.stdout.softspace = -1:ValueError:('number must be greater or equal to zero',)
+<<< Finished
+>>> Testing NumberToLong using sys.stderr.softspace = %s
+sys.stderr.softspace = []:TypeError:('expected int(), long() or something supporting coercing to long(), but got list',)
+sys.stderr.softspace = None:TypeError:('expected int(), long() or something supporting coercing to long(), but got NoneType',)
+sys.stderr.softspace = -1:ValueError:('number must be greater or equal to zero',)
+<<< Finished
 sys.stdout.attr = None:AttributeError:('invalid attribute: attr',)
 >> OutputWrite
 sys.stdout.write(None):TypeError:('coercing to Unicode: need string or buffer, NoneType found',)
 >> OutputWriteLines
 sys.stdout.writelines(None):TypeError:("'NoneType' object is not iterable",)
 sys.stdout.writelines([1]):TypeError:('coercing to Unicode: need string or buffer, int found',)
+>>> Testing *Iter* using sys.stdout.writelines(%s)
+sys.stdout.writelines(FailingIter()):NotImplementedError:('iter',)
+sys.stdout.writelines(FailingIterNext()):NotImplementedError:('next',)
+<<< Finished
 > VimCommand
+>>> Testing StringToChars using vim.command(%s)
 vim.command(1):TypeError:('expected str() or unicode() instance, but got int',)
+vim.command(u"\0"):TypeError:('expected string without null bytes',)
+vim.command("\0"):TypeError:('expected string without null bytes',)
+<<< Finished
+vim.command("", 2):TypeError:('command() takes exactly one argument (2 given)',)
 > VimToPython
 > VimEval
+>>> Testing StringToChars using vim.eval(%s)
 vim.eval(1):TypeError:('expected str() or unicode() instance, but got int',)
+vim.eval(u"\0"):TypeError:('expected string without null bytes',)
+vim.eval("\0"):TypeError:('expected string without null bytes',)
+<<< Finished
+vim.eval("", FailingTrue()):TypeError:('function takes exactly 1 argument (2 given)',)
 > VimEvalPy
+>>> Testing StringToChars using vim.bindeval(%s)
 vim.bindeval(1):TypeError:('expected str() or unicode() instance, but got int',)
+vim.bindeval(u"\0"):TypeError:('expected string without null bytes',)
+vim.bindeval("\0"):TypeError:('expected string without null bytes',)
+<<< Finished
+vim.eval("", 2):TypeError:('function takes exactly 1 argument (2 given)',)
 > VimStrwidth
+>>> Testing StringToChars using vim.strwidth(%s)
 vim.strwidth(1):TypeError:('expected str() or unicode() instance, but got int',)
+vim.strwidth(u"\0"):TypeError:('expected string without null bytes',)
+vim.strwidth("\0"):TypeError:('expected string without null bytes',)
+<<< Finished
+> VimForeachRTP
+vim.foreach_rtp(None):TypeError:("'NoneType' object is not callable",)
+vim.foreach_rtp(NoArgsCall()):TypeError:('__call__() takes exactly 1 argument (2 given)',)
+vim.foreach_rtp(FailingCall()):NotImplementedError:('call',)
+vim.foreach_rtp(int, 2):TypeError:('foreach_rtp() takes exactly one argument (2 given)',)
+> import
+import xxx_no_such_module_xxx:ImportError:('No module named xxx_no_such_module_xxx',)
+import failing_import:ImportError:('No module named failing_import',)
+import failing:ImportError:('No module named failing',)
 > Dictionary
 >> DictionaryConstructor
 vim.Dictionary("abcI"):ValueError:('expected sequence element of size 2, but got sequence of size 1',)
 >> DictionarySetattr
 del d.locked:AttributeError:('cannot delete vim.Dictionary attributes',)
-d.locked = FailingTrue():NotImplementedError:()
+d.locked = FailingTrue():NotImplementedError:('bool',)
 vim.vvars.locked = False:TypeError:('cannot modify fixed dictionary',)
 d.scope = True:AttributeError:('cannot set attribute scope',)
 d.xxx = True:AttributeError:('cannot set attribute xxx',)
@@ -501,14 +542,15 @@
 <<< Finished
 >>> Testing *Iter* using d["a"] = {"abcF" : %s}
 d["a"] = {"abcF" : FailingIter()}:TypeError:('unable to convert FailingIter to vim structure',)
-d["a"] = {"abcF" : FailingIterNext()}:NotImplementedError:()
+d["a"] = {"abcF" : FailingIterNext()}:NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using d["a"] = {"abcF" : %s}
 d["a"] = {"abcF" : None}:TypeError:('unable to convert NoneType to vim structure',)
 d["a"] = {"abcF" : {"": 1}}:ValueError:('empty keys are not allowed',)
 d["a"] = {"abcF" : {u"": 1}}:ValueError:('empty keys are not allowed',)
-d["a"] = {"abcF" : FailingMapping()}:NotImplementedError:()
-d["a"] = {"abcF" : FailingMappingKey()}:NotImplementedError:()
+d["a"] = {"abcF" : FailingMapping()}:NotImplementedError:('keys',)
+d["a"] = {"abcF" : FailingMappingKey()}:NotImplementedError:('getitem:mappingkey',)
+d["a"] = {"abcF" : FailingNumber()}:TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing StringToChars using d["a"] = Mapping({%s : 1})
 d["a"] = Mapping({1 : 1}):TypeError:('expected str() or unicode() instance, but got int',)
@@ -527,31 +569,37 @@
 <<< Finished
 >>> Testing *Iter* using d["a"] = Mapping({"abcG" : %s})
 d["a"] = Mapping({"abcG" : FailingIter()}):TypeError:('unable to convert FailingIter to vim structure',)
-d["a"] = Mapping({"abcG" : FailingIterNext()}):NotImplementedError:()
+d["a"] = Mapping({"abcG" : FailingIterNext()}):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using d["a"] = Mapping({"abcG" : %s})
 d["a"] = Mapping({"abcG" : None}):TypeError:('unable to convert NoneType to vim structure',)
 d["a"] = Mapping({"abcG" : {"": 1}}):ValueError:('empty keys are not allowed',)
 d["a"] = Mapping({"abcG" : {u"": 1}}):ValueError:('empty keys are not allowed',)
-d["a"] = Mapping({"abcG" : FailingMapping()}):NotImplementedError:()
-d["a"] = Mapping({"abcG" : FailingMappingKey()}):NotImplementedError:()
+d["a"] = Mapping({"abcG" : FailingMapping()}):NotImplementedError:('keys',)
+d["a"] = Mapping({"abcG" : FailingMappingKey()}):NotImplementedError:('getitem:mappingkey',)
+d["a"] = Mapping({"abcG" : FailingNumber()}):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing *Iter* using d["a"] = %s
 d["a"] = FailingIter():TypeError:('unable to convert FailingIter to vim structure',)
-d["a"] = FailingIterNext():NotImplementedError:()
+d["a"] = FailingIterNext():NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using d["a"] = %s
 d["a"] = None:TypeError:('unable to convert NoneType to vim structure',)
 d["a"] = {"": 1}:ValueError:('empty keys are not allowed',)
 d["a"] = {u"": 1}:ValueError:('empty keys are not allowed',)
-d["a"] = FailingMapping():NotImplementedError:()
-d["a"] = FailingMappingKey():NotImplementedError:()
+d["a"] = FailingMapping():NotImplementedError:('keys',)
+d["a"] = FailingMappingKey():NotImplementedError:('getitem:mappingkey',)
+d["a"] = FailingNumber():TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >> DictionaryUpdate
 >>> kwargs
 >>> iter
-d.update(FailingMapping()):NotImplementedError:()
-d.update([FailingIterNext()]):NotImplementedError:()
+d.update(FailingMapping()):NotImplementedError:('keys',)
+d.update([FailingIterNext()]):NotImplementedError:('next',)
+>>> Testing *Iter* using d.update(%s)
+d.update(FailingIter()):NotImplementedError:('iter',)
+d.update(FailingIterNext()):NotImplementedError:('next',)
+<<< Finished
 >>> Testing StringToChars using d.update({%s : 1})
 d.update({1 : 1}):TypeError:('expected str() or unicode() instance, but got int',)
 d.update({u"\0" : 1}):TypeError:('expected string without null bytes',)
@@ -569,14 +617,15 @@
 <<< Finished
 >>> Testing *Iter* using d.update({"abcF" : %s})
 d.update({"abcF" : FailingIter()}):TypeError:('unable to convert FailingIter to vim structure',)
-d.update({"abcF" : FailingIterNext()}):NotImplementedError:()
+d.update({"abcF" : FailingIterNext()}):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update({"abcF" : %s})
 d.update({"abcF" : None}):TypeError:('unable to convert NoneType to vim structure',)
 d.update({"abcF" : {"": 1}}):ValueError:('empty keys are not allowed',)
 d.update({"abcF" : {u"": 1}}):ValueError:('empty keys are not allowed',)
-d.update({"abcF" : FailingMapping()}):NotImplementedError:()
-d.update({"abcF" : FailingMappingKey()}):NotImplementedError:()
+d.update({"abcF" : FailingMapping()}):NotImplementedError:('keys',)
+d.update({"abcF" : FailingMappingKey()}):NotImplementedError:('getitem:mappingkey',)
+d.update({"abcF" : FailingNumber()}):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing StringToChars using d.update(Mapping({%s : 1}))
 d.update(Mapping({1 : 1})):TypeError:('expected str() or unicode() instance, but got int',)
@@ -595,25 +644,27 @@
 <<< Finished
 >>> Testing *Iter* using d.update(Mapping({"abcG" : %s}))
 d.update(Mapping({"abcG" : FailingIter()})):TypeError:('unable to convert FailingIter to vim structure',)
-d.update(Mapping({"abcG" : FailingIterNext()})):NotImplementedError:()
+d.update(Mapping({"abcG" : FailingIterNext()})):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update(Mapping({"abcG" : %s}))
 d.update(Mapping({"abcG" : None})):TypeError:('unable to convert NoneType to vim structure',)
 d.update(Mapping({"abcG" : {"": 1}})):ValueError:('empty keys are not allowed',)
 d.update(Mapping({"abcG" : {u"": 1}})):ValueError:('empty keys are not allowed',)
-d.update(Mapping({"abcG" : FailingMapping()})):NotImplementedError:()
-d.update(Mapping({"abcG" : FailingMappingKey()})):NotImplementedError:()
+d.update(Mapping({"abcG" : FailingMapping()})):NotImplementedError:('keys',)
+d.update(Mapping({"abcG" : FailingMappingKey()})):NotImplementedError:('getitem:mappingkey',)
+d.update(Mapping({"abcG" : FailingNumber()})):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing *Iter* using d.update(%s)
-d.update(FailingIter()):NotImplementedError:()
-d.update(FailingIterNext()):NotImplementedError:()
+d.update(FailingIter()):NotImplementedError:('iter',)
+d.update(FailingIterNext()):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update(%s)
 d.update(None):TypeError:("'NoneType' object is not iterable",)
 d.update({"": 1}):ValueError:('empty keys are not allowed',)
 d.update({u"": 1}):ValueError:('empty keys are not allowed',)
-d.update(FailingMapping()):NotImplementedError:()
-d.update(FailingMappingKey()):NotImplementedError:()
+d.update(FailingMapping()):NotImplementedError:('keys',)
+d.update(FailingMappingKey()):NotImplementedError:('getitem:mappingkey',)
+d.update(FailingNumber()):TypeError:("'FailingNumber' object is not iterable",)
 <<< Finished
 >>> Testing StringToChars using d.update(((%s, 0),))
 d.update(((1, 0),)):TypeError:('expected str() or unicode() instance, but got int',)
@@ -637,14 +688,15 @@
 <<< Finished
 >>> Testing *Iter* using d.update((("a", {"abcF" : %s}),))
 d.update((("a", {"abcF" : FailingIter()}),)):TypeError:('unable to convert FailingIter to vim structure',)
-d.update((("a", {"abcF" : FailingIterNext()}),)):NotImplementedError:()
+d.update((("a", {"abcF" : FailingIterNext()}),)):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update((("a", {"abcF" : %s}),))
 d.update((("a", {"abcF" : None}),)):TypeError:('unable to convert NoneType to vim structure',)
 d.update((("a", {"abcF" : {"": 1}}),)):ValueError:('empty keys are not allowed',)
 d.update((("a", {"abcF" : {u"": 1}}),)):ValueError:('empty keys are not allowed',)
-d.update((("a", {"abcF" : FailingMapping()}),)):NotImplementedError:()
-d.update((("a", {"abcF" : FailingMappingKey()}),)):NotImplementedError:()
+d.update((("a", {"abcF" : FailingMapping()}),)):NotImplementedError:('keys',)
+d.update((("a", {"abcF" : FailingMappingKey()}),)):NotImplementedError:('getitem:mappingkey',)
+d.update((("a", {"abcF" : FailingNumber()}),)):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing StringToChars using d.update((("a", Mapping({%s : 1})),))
 d.update((("a", Mapping({1 : 1})),)):TypeError:('expected str() or unicode() instance, but got int',)
@@ -663,25 +715,27 @@
 <<< Finished
 >>> Testing *Iter* using d.update((("a", Mapping({"abcG" : %s})),))
 d.update((("a", Mapping({"abcG" : FailingIter()})),)):TypeError:('unable to convert FailingIter to vim structure',)
-d.update((("a", Mapping({"abcG" : FailingIterNext()})),)):NotImplementedError:()
+d.update((("a", Mapping({"abcG" : FailingIterNext()})),)):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update((("a", Mapping({"abcG" : %s})),))
 d.update((("a", Mapping({"abcG" : None})),)):TypeError:('unable to convert NoneType to vim structure',)
 d.update((("a", Mapping({"abcG" : {"": 1}})),)):ValueError:('empty keys are not allowed',)
 d.update((("a", Mapping({"abcG" : {u"": 1}})),)):ValueError:('empty keys are not allowed',)
-d.update((("a", Mapping({"abcG" : FailingMapping()})),)):NotImplementedError:()
-d.update((("a", Mapping({"abcG" : FailingMappingKey()})),)):NotImplementedError:()
+d.update((("a", Mapping({"abcG" : FailingMapping()})),)):NotImplementedError:('keys',)
+d.update((("a", Mapping({"abcG" : FailingMappingKey()})),)):NotImplementedError:('getitem:mappingkey',)
+d.update((("a", Mapping({"abcG" : FailingNumber()})),)):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing *Iter* using d.update((("a", %s),))
 d.update((("a", FailingIter()),)):TypeError:('unable to convert FailingIter to vim structure',)
-d.update((("a", FailingIterNext()),)):NotImplementedError:()
+d.update((("a", FailingIterNext()),)):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update((("a", %s),))
 d.update((("a", None),)):TypeError:('unable to convert NoneType to vim structure',)
 d.update((("a", {"": 1}),)):ValueError:('empty keys are not allowed',)
 d.update((("a", {u"": 1}),)):ValueError:('empty keys are not allowed',)
-d.update((("a", FailingMapping()),)):NotImplementedError:()
-d.update((("a", FailingMappingKey()),)):NotImplementedError:()
+d.update((("a", FailingMapping()),)):NotImplementedError:('keys',)
+d.update((("a", FailingMappingKey()),)):NotImplementedError:('getitem:mappingkey',)
+d.update((("a", FailingNumber()),)):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >> DictionaryPopItem
 d.popitem(1, 2):TypeError:('popitem() takes no arguments (2 given)',)
@@ -691,6 +745,10 @@
 >> ListConstructor
 vim.List(1, 2):TypeError:('function takes at most 1 argument (2 given)',)
 vim.List(a=1):TypeError:('list constructor does not accept keyword arguments',)
+>>> Testing *Iter* using vim.List(%s)
+vim.List(FailingIter()):NotImplementedError:('iter',)
+vim.List(FailingIterNext()):NotImplementedError:('next',)
+<<< Finished
 >>> Testing StringToChars using vim.List([{%s : 1}])
 vim.List([{1 : 1}]):TypeError:('expected str() or unicode() instance, but got int',)
 vim.List([{u"\0" : 1}]):TypeError:('expected string without null bytes',)
@@ -708,14 +766,15 @@
 <<< Finished
 >>> Testing *Iter* using vim.List([{"abcF" : %s}])
 vim.List([{"abcF" : FailingIter()}]):TypeError:('unable to convert FailingIter to vim structure',)
-vim.List([{"abcF" : FailingIterNext()}]):NotImplementedError:()
+vim.List([{"abcF" : FailingIterNext()}]):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using vim.List([{"abcF" : %s}])
 vim.List([{"abcF" : None}]):TypeError:('unable to convert NoneType to vim structure',)
 vim.List([{"abcF" : {"": 1}}]):ValueError:('empty keys are not allowed',)
 vim.List([{"abcF" : {u"": 1}}]):ValueError:('empty keys are not allowed',)
-vim.List([{"abcF" : FailingMapping()}]):NotImplementedError:()
-vim.List([{"abcF" : FailingMappingKey()}]):NotImplementedError:()
+vim.List([{"abcF" : FailingMapping()}]):NotImplementedError:('keys',)
+vim.List([{"abcF" : FailingMappingKey()}]):NotImplementedError:('getitem:mappingkey',)
+vim.List([{"abcF" : FailingNumber()}]):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing StringToChars using vim.List([Mapping({%s : 1})])
 vim.List([Mapping({1 : 1})]):TypeError:('expected str() or unicode() instance, but got int',)
@@ -734,25 +793,27 @@
 <<< Finished
 >>> Testing *Iter* using vim.List([Mapping({"abcG" : %s})])
 vim.List([Mapping({"abcG" : FailingIter()})]):TypeError:('unable to convert FailingIter to vim structure',)
-vim.List([Mapping({"abcG" : FailingIterNext()})]):NotImplementedError:()
+vim.List([Mapping({"abcG" : FailingIterNext()})]):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using vim.List([Mapping({"abcG" : %s})])
 vim.List([Mapping({"abcG" : None})]):TypeError:('unable to convert NoneType to vim structure',)
 vim.List([Mapping({"abcG" : {"": 1}})]):ValueError:('empty keys are not allowed',)
 vim.List([Mapping({"abcG" : {u"": 1}})]):ValueError:('empty keys are not allowed',)
-vim.List([Mapping({"abcG" : FailingMapping()})]):NotImplementedError:()
-vim.List([Mapping({"abcG" : FailingMappingKey()})]):NotImplementedError:()
+vim.List([Mapping({"abcG" : FailingMapping()})]):NotImplementedError:('keys',)
+vim.List([Mapping({"abcG" : FailingMappingKey()})]):NotImplementedError:('getitem:mappingkey',)
+vim.List([Mapping({"abcG" : FailingNumber()})]):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing *Iter* using vim.List([%s])
 vim.List([FailingIter()]):TypeError:('unable to convert FailingIter to vim structure',)
-vim.List([FailingIterNext()]):NotImplementedError:()
+vim.List([FailingIterNext()]):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using vim.List([%s])
 vim.List([None]):TypeError:('unable to convert NoneType to vim structure',)
 vim.List([{"": 1}]):ValueError:('empty keys are not allowed',)
 vim.List([{u"": 1}]):ValueError:('empty keys are not allowed',)
-vim.List([FailingMapping()]):NotImplementedError:()
-vim.List([FailingMappingKey()]):NotImplementedError:()
+vim.List([FailingMapping()]):NotImplementedError:('keys',)
+vim.List([FailingMappingKey()]):NotImplementedError:('getitem:mappingkey',)
+vim.List([FailingNumber()]):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >> ListItem
 l[1000]:IndexError:('list index out of range',)
@@ -761,6 +822,10 @@
 l[1000] = 3:IndexError:('list index out of range',)
 >> ListAssSlice
 ll[1:100] = "abcJ":error:('list is locked',)
+>>> Testing *Iter* using l[:] = %s
+l[:] = FailingIter():NotImplementedError:('iter',)
+l[:] = FailingIterNext():NotImplementedError:('next',)
+<<< Finished
 >>> Testing StringToChars using l[:] = [{%s : 1}]
 l[:] = [{1 : 1}]:TypeError:('expected str() or unicode() instance, but got int',)
 l[:] = [{u"\0" : 1}]:TypeError:('expected string without null bytes',)
@@ -778,14 +843,15 @@
 <<< Finished
 >>> Testing *Iter* using l[:] = [{"abcF" : %s}]
 l[:] = [{"abcF" : FailingIter()}]:TypeError:('unable to convert FailingIter to vim structure',)
-l[:] = [{"abcF" : FailingIterNext()}]:NotImplementedError:()
+l[:] = [{"abcF" : FailingIterNext()}]:NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using l[:] = [{"abcF" : %s}]
 l[:] = [{"abcF" : None}]:TypeError:('unable to convert NoneType to vim structure',)
 l[:] = [{"abcF" : {"": 1}}]:ValueError:('empty keys are not allowed',)
 l[:] = [{"abcF" : {u"": 1}}]:ValueError:('empty keys are not allowed',)
-l[:] = [{"abcF" : FailingMapping()}]:NotImplementedError:()
-l[:] = [{"abcF" : FailingMappingKey()}]:NotImplementedError:()
+l[:] = [{"abcF" : FailingMapping()}]:NotImplementedError:('keys',)
+l[:] = [{"abcF" : FailingMappingKey()}]:NotImplementedError:('getitem:mappingkey',)
+l[:] = [{"abcF" : FailingNumber()}]:TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing StringToChars using l[:] = [Mapping({%s : 1})]
 l[:] = [Mapping({1 : 1})]:TypeError:('expected str() or unicode() instance, but got int',)
@@ -804,27 +870,33 @@
 <<< Finished
 >>> Testing *Iter* using l[:] = [Mapping({"abcG" : %s})]
 l[:] = [Mapping({"abcG" : FailingIter()})]:TypeError:('unable to convert FailingIter to vim structure',)
-l[:] = [Mapping({"abcG" : FailingIterNext()})]:NotImplementedError:()
+l[:] = [Mapping({"abcG" : FailingIterNext()})]:NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using l[:] = [Mapping({"abcG" : %s})]
 l[:] = [Mapping({"abcG" : None})]:TypeError:('unable to convert NoneType to vim structure',)
 l[:] = [Mapping({"abcG" : {"": 1}})]:ValueError:('empty keys are not allowed',)
 l[:] = [Mapping({"abcG" : {u"": 1}})]:ValueError:('empty keys are not allowed',)
-l[:] = [Mapping({"abcG" : FailingMapping()})]:NotImplementedError:()
-l[:] = [Mapping({"abcG" : FailingMappingKey()})]:NotImplementedError:()
+l[:] = [Mapping({"abcG" : FailingMapping()})]:NotImplementedError:('keys',)
+l[:] = [Mapping({"abcG" : FailingMappingKey()})]:NotImplementedError:('getitem:mappingkey',)
+l[:] = [Mapping({"abcG" : FailingNumber()})]:TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing *Iter* using l[:] = [%s]
 l[:] = [FailingIter()]:TypeError:('unable to convert FailingIter to vim structure',)
-l[:] = [FailingIterNext()]:NotImplementedError:()
+l[:] = [FailingIterNext()]:NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using l[:] = [%s]
 l[:] = [None]:TypeError:('unable to convert NoneType to vim structure',)
 l[:] = [{"": 1}]:ValueError:('empty keys are not allowed',)
 l[:] = [{u"": 1}]:ValueError:('empty keys are not allowed',)
-l[:] = [FailingMapping()]:NotImplementedError:()
-l[:] = [FailingMappingKey()]:NotImplementedError:()
+l[:] = [FailingMapping()]:NotImplementedError:('keys',)
+l[:] = [FailingMappingKey()]:NotImplementedError:('getitem:mappingkey',)
+l[:] = [FailingNumber()]:TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >> ListConcatInPlace
+>>> Testing *Iter* using l.extend(%s)
+l.extend(FailingIter()):NotImplementedError:('iter',)
+l.extend(FailingIterNext()):NotImplementedError:('next',)
+<<< Finished
 >>> Testing StringToChars using l.extend([{%s : 1}])
 l.extend([{1 : 1}]):TypeError:('expected str() or unicode() instance, but got int',)
 l.extend([{u"\0" : 1}]):TypeError:('expected string without null bytes',)
@@ -842,14 +914,15 @@
 <<< Finished
 >>> Testing *Iter* using l.extend([{"abcF" : %s}])
 l.extend([{"abcF" : FailingIter()}]):TypeError:('unable to convert FailingIter to vim structure',)
-l.extend([{"abcF" : FailingIterNext()}]):NotImplementedError:()
+l.extend([{"abcF" : FailingIterNext()}]):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using l.extend([{"abcF" : %s}])
 l.extend([{"abcF" : None}]):TypeError:('unable to convert NoneType to vim structure',)
 l.extend([{"abcF" : {"": 1}}]):ValueError:('empty keys are not allowed',)
 l.extend([{"abcF" : {u"": 1}}]):ValueError:('empty keys are not allowed',)
-l.extend([{"abcF" : FailingMapping()}]):NotImplementedError:()
-l.extend([{"abcF" : FailingMappingKey()}]):NotImplementedError:()
+l.extend([{"abcF" : FailingMapping()}]):NotImplementedError:('keys',)
+l.extend([{"abcF" : FailingMappingKey()}]):NotImplementedError:('getitem:mappingkey',)
+l.extend([{"abcF" : FailingNumber()}]):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing StringToChars using l.extend([Mapping({%s : 1})])
 l.extend([Mapping({1 : 1})]):TypeError:('expected str() or unicode() instance, but got int',)
@@ -868,29 +941,31 @@
 <<< Finished
 >>> Testing *Iter* using l.extend([Mapping({"abcG" : %s})])
 l.extend([Mapping({"abcG" : FailingIter()})]):TypeError:('unable to convert FailingIter to vim structure',)
-l.extend([Mapping({"abcG" : FailingIterNext()})]):NotImplementedError:()
+l.extend([Mapping({"abcG" : FailingIterNext()})]):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using l.extend([Mapping({"abcG" : %s})])
 l.extend([Mapping({"abcG" : None})]):TypeError:('unable to convert NoneType to vim structure',)
 l.extend([Mapping({"abcG" : {"": 1}})]):ValueError:('empty keys are not allowed',)
 l.extend([Mapping({"abcG" : {u"": 1}})]):ValueError:('empty keys are not allowed',)
-l.extend([Mapping({"abcG" : FailingMapping()})]):NotImplementedError:()
-l.extend([Mapping({"abcG" : FailingMappingKey()})]):NotImplementedError:()
+l.extend([Mapping({"abcG" : FailingMapping()})]):NotImplementedError:('keys',)
+l.extend([Mapping({"abcG" : FailingMappingKey()})]):NotImplementedError:('getitem:mappingkey',)
+l.extend([Mapping({"abcG" : FailingNumber()})]):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing *Iter* using l.extend([%s])
 l.extend([FailingIter()]):TypeError:('unable to convert FailingIter to vim structure',)
-l.extend([FailingIterNext()]):NotImplementedError:()
+l.extend([FailingIterNext()]):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using l.extend([%s])
 l.extend([None]):TypeError:('unable to convert NoneType to vim structure',)
 l.extend([{"": 1}]):ValueError:('empty keys are not allowed',)
 l.extend([{u"": 1}]):ValueError:('empty keys are not allowed',)
-l.extend([FailingMapping()]):NotImplementedError:()
-l.extend([FailingMappingKey()]):NotImplementedError:()
+l.extend([FailingMapping()]):NotImplementedError:('keys',)
+l.extend([FailingMappingKey()]):NotImplementedError:('getitem:mappingkey',)
+l.extend([FailingNumber()]):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >> ListSetattr
 del l.locked:AttributeError:('cannot delete vim.List attributes',)
-l.locked = FailingTrue():NotImplementedError:()
+l.locked = FailingTrue():NotImplementedError:('bool',)
 l.xxx = True:AttributeError:('cannot set attribute xxx',)
 > Function
 >> FunctionConstructor
@@ -915,14 +990,15 @@
 <<< Finished
 >>> Testing *Iter* using f({"abcF" : %s})
 f({"abcF" : FailingIter()}):TypeError:('unable to convert FailingIter to vim structure',)
-f({"abcF" : FailingIterNext()}):NotImplementedError:()
+f({"abcF" : FailingIterNext()}):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using f({"abcF" : %s})
 f({"abcF" : None}):TypeError:('unable to convert NoneType to vim structure',)
 f({"abcF" : {"": 1}}):ValueError:('empty keys are not allowed',)
 f({"abcF" : {u"": 1}}):ValueError:('empty keys are not allowed',)
-f({"abcF" : FailingMapping()}):NotImplementedError:()
-f({"abcF" : FailingMappingKey()}):NotImplementedError:()
+f({"abcF" : FailingMapping()}):NotImplementedError:('keys',)
+f({"abcF" : FailingMappingKey()}):NotImplementedError:('getitem:mappingkey',)
+f({"abcF" : FailingNumber()}):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing StringToChars using f(Mapping({%s : 1}))
 f(Mapping({1 : 1})):TypeError:('expected str() or unicode() instance, but got int',)
@@ -941,25 +1017,27 @@
 <<< Finished
 >>> Testing *Iter* using f(Mapping({"abcG" : %s}))
 f(Mapping({"abcG" : FailingIter()})):TypeError:('unable to convert FailingIter to vim structure',)
-f(Mapping({"abcG" : FailingIterNext()})):NotImplementedError:()
+f(Mapping({"abcG" : FailingIterNext()})):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using f(Mapping({"abcG" : %s}))
 f(Mapping({"abcG" : None})):TypeError:('unable to convert NoneType to vim structure',)
 f(Mapping({"abcG" : {"": 1}})):ValueError:('empty keys are not allowed',)
 f(Mapping({"abcG" : {u"": 1}})):ValueError:('empty keys are not allowed',)
-f(Mapping({"abcG" : FailingMapping()})):NotImplementedError:()
-f(Mapping({"abcG" : FailingMappingKey()})):NotImplementedError:()
+f(Mapping({"abcG" : FailingMapping()})):NotImplementedError:('keys',)
+f(Mapping({"abcG" : FailingMappingKey()})):NotImplementedError:('getitem:mappingkey',)
+f(Mapping({"abcG" : FailingNumber()})):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing *Iter* using f(%s)
 f(FailingIter()):TypeError:('unable to convert FailingIter to vim structure',)
-f(FailingIterNext()):NotImplementedError:()
+f(FailingIterNext()):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using f(%s)
 f(None):TypeError:('unable to convert NoneType to vim structure',)
 f({"": 1}):ValueError:('empty keys are not allowed',)
 f({u"": 1}):ValueError:('empty keys are not allowed',)
-f(FailingMapping()):NotImplementedError:()
-f(FailingMappingKey()):NotImplementedError:()
+f(FailingMapping()):NotImplementedError:('keys',)
+f(FailingMappingKey()):NotImplementedError:('getitem:mappingkey',)
+f(FailingNumber()):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing StringToChars using fd(self={%s : 1})
 fd(self={1 : 1}):TypeError:('expected str() or unicode() instance, but got int',)
@@ -978,14 +1056,15 @@
 <<< Finished
 >>> Testing *Iter* using fd(self={"abcF" : %s})
 fd(self={"abcF" : FailingIter()}):TypeError:('unable to convert FailingIter to vim structure',)
-fd(self={"abcF" : FailingIterNext()}):NotImplementedError:()
+fd(self={"abcF" : FailingIterNext()}):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using fd(self={"abcF" : %s})
 fd(self={"abcF" : None}):TypeError:('unable to convert NoneType to vim structure',)
 fd(self={"abcF" : {"": 1}}):ValueError:('empty keys are not allowed',)
 fd(self={"abcF" : {u"": 1}}):ValueError:('empty keys are not allowed',)
-fd(self={"abcF" : FailingMapping()}):NotImplementedError:()
-fd(self={"abcF" : FailingMappingKey()}):NotImplementedError:()
+fd(self={"abcF" : FailingMapping()}):NotImplementedError:('keys',)
+fd(self={"abcF" : FailingMappingKey()}):NotImplementedError:('getitem:mappingkey',)
+fd(self={"abcF" : FailingNumber()}):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing StringToChars using fd(self=Mapping({%s : 1}))
 fd(self=Mapping({1 : 1})):TypeError:('expected str() or unicode() instance, but got int',)
@@ -1004,14 +1083,15 @@
 <<< Finished
 >>> Testing *Iter* using fd(self=Mapping({"abcG" : %s}))
 fd(self=Mapping({"abcG" : FailingIter()})):TypeError:('unable to convert FailingIter to vim structure',)
-fd(self=Mapping({"abcG" : FailingIterNext()})):NotImplementedError:()
+fd(self=Mapping({"abcG" : FailingIterNext()})):NotImplementedError:('next',)
 <<< Finished
 >>> Testing ConvertFromPyObject using fd(self=Mapping({"abcG" : %s}))
 fd(self=Mapping({"abcG" : None})):TypeError:('unable to convert NoneType to vim structure',)
 fd(self=Mapping({"abcG" : {"": 1}})):ValueError:('empty keys are not allowed',)
 fd(self=Mapping({"abcG" : {u"": 1}})):ValueError:('empty keys are not allowed',)
-fd(self=Mapping({"abcG" : FailingMapping()})):NotImplementedError:()
-fd(self=Mapping({"abcG" : FailingMappingKey()})):NotImplementedError:()
+fd(self=Mapping({"abcG" : FailingMapping()})):NotImplementedError:('keys',)
+fd(self=Mapping({"abcG" : FailingMappingKey()})):NotImplementedError:('getitem:mappingkey',)
+fd(self=Mapping({"abcG" : FailingNumber()})):TypeError:('long() argument must be a string or a number',)
 <<< Finished
 >>> Testing *Iter* using fd(self=%s)
 fd(self=FailingIter()):TypeError:('unable to convert FailingIter to vim dictionary',)
@@ -1021,8 +1101,9 @@
 fd(self=None):TypeError:('unable to convert NoneType to vim dictionary',)
 fd(self={"": 1}):ValueError:('empty keys are not allowed',)
 fd(self={u"": 1}):ValueError:('empty keys are not allowed',)
-fd(self=FailingMapping()):NotImplementedError:()
-fd(self=FailingMappingKey()):NotImplementedError:()
+fd(self=FailingMapping()):NotImplementedError:('keys',)
+fd(self=FailingMappingKey()):NotImplementedError:('getitem:mappingkey',)
+fd(self=FailingNumber()):TypeError:('unable to convert FailingNumber to vim dictionary',)
 <<< Finished
 >>> Testing ConvertFromPyMapping using fd(self=%s)
 fd(self=[]):TypeError:('unable to convert list to vim dictionary',)
@@ -1040,14 +1121,23 @@
 vim.current.window.buffer = 0:TypeError:('readonly attribute: buffer',)
 vim.current.window.cursor = (100000000, 100000000):error:('cursor position outside buffer',)
 vim.current.window.cursor = True:TypeError:('argument must be 2-item sequence, not bool',)
-vim.current.window.height = "abcK":TypeError:('expected int(), long() or something supporting coercing to long(), but got str',)
-vim.current.window.width  = "abcL":TypeError:('expected int(), long() or something supporting coercing to long(), but got str',)
+>>> Testing NumberToLong using vim.current.window.height = %s
+vim.current.window.height = []:TypeError:('expected int(), long() or something supporting coercing to long(), but got list',)
+vim.current.window.height = None:TypeError:('expected int(), long() or something supporting coercing to long(), but got NoneType',)
+vim.current.window.height = -1:ValueError:('number must be greater or equal to zero',)
+<<< Finished
+>>> Testing NumberToLong using vim.current.window.width = %s
+vim.current.window.width = []:TypeError:('expected int(), long() or something supporting coercing to long(), but got list',)
+vim.current.window.width = None:TypeError:('expected int(), long() or something supporting coercing to long(), but got NoneType',)
+vim.current.window.width = -1:ValueError:('number must be greater or equal to zero',)
+<<< Finished
 vim.current.window.xxxxxx = True:AttributeError:('xxxxxx',)
 > WinList
 >> WinListItem
 vim.windows[1000]:IndexError:('no such window',)
 > Buffer
 >> StringToLine (indirect)
+vim.current.buffer[0] = u"\na":error:('string cannot contain newlines',)
 vim.current.buffer[0] = "\na":error:('string cannot contain newlines',)
 >> SetBufferLine (indirect)
 vim.current.buffer[0] = True:TypeError:('bad argument type for built-in operation',)
@@ -1075,8 +1165,13 @@
 vim.current.buffer.range(1, 2, 3):TypeError:('function takes exactly 2 arguments (3 given)',)
 > BufMap
 >> BufMapItem
-vim.buffers[None]:TypeError:('expected int(), long() or something supporting coercing to long(), but got NoneType',)
 vim.buffers[100000000]:KeyError:(100000000,)
+>>> Testing NumberToLong using vim.buffers[%s]
+vim.buffers[[]]:TypeError:('expected int(), long() or something supporting coercing to long(), but got list',)
+vim.buffers[None]:TypeError:('expected int(), long() or something supporting coercing to long(), but got NoneType',)
+vim.buffers[-1]:ValueError:('number must be greater then zero',)
+vim.buffers[0]:ValueError:('number must be greater then zero',)
+<<< Finished
 > Current
 >> CurrentGetattr
 vim.current.xxx:AttributeError:('xxx',)
@@ -1086,9 +1181,14 @@
 vim.current.window = True:TypeError:('expected vim.Window object, but got bool',)
 vim.current.tabpage = True:TypeError:('expected vim.TabPage object, but got bool',)
 vim.current.xxx = True:AttributeError:('xxx',)
+['/testdir']
+'/testdir'
 2,xx
 before
 after
+pythonx/topmodule/__init__.py
+pythonx/topmodule/submodule/__init__.py
+pythonx/topmodule/submodule/subsubmodule/subsubsubmodule.py
 vim.command("throw 'abcN'"):error:('abcN',)
 Exe("throw 'def'"):error:('def',)
 vim.eval("Exe('throw ''ghi''')"):error:('ghi',)
diff --git a/src/testdir/test87.in b/src/testdir/test87.in
index 6b89117..88a8d88 100644
--- a/src/testdir/test87.in
+++ b/src/testdir/test87.in
@@ -290,7 +290,7 @@
 :" threading
 :let l = [0]
 :py3 l=vim.bindeval('l')
-:py3 <<EOF
+py3 <<EOF
 import threading
 import time
 
@@ -320,7 +320,7 @@
 :" settrace
 :let l = []
 :py3 l=vim.bindeval('l')
-:py3 <<EOF
+py3 <<EOF
 import sys
 
 def traceit(frame, event, arg):
@@ -335,9 +335,9 @@
 EOF
 :py3 sys.settrace(traceit)
 :py3 trace_main()
+:py3 sys.settrace(None)
 :py3 del traceit
 :py3 del trace_main
-:py3 sys.settrace(None)
 :$put =string(l)
 :"
 :" Vars
@@ -898,6 +898,7 @@
         '{"": 1}',              # Same, but with unicode object
         'FailingMapping()',     #
         'FailingMappingKey()',  #
+        'FailingNumber()',      #
     ))
 
 def convertfrompymapping_test(expr):
@@ -912,46 +913,68 @@
         'FailingIterNext()',
     ))
 
+def number_test(expr, natural=False, unsigned=False):
+    if natural:
+        unsigned = True
+    return subexpr_test(expr, 'NumberToLong', (
+        '[]',
+        'None',
+    ) + (('-1',) if unsigned else ())
+    + (('0',) if natural else ()))
+
 class FailingTrue(object):
     def __bool__(self):
-        raise NotImplementedError
+        raise NotImplementedError('bool')
 
 class FailingIter(object):
     def __iter__(self):
-        raise NotImplementedError
+        raise NotImplementedError('iter')
 
 class FailingIterNext(object):
     def __iter__(self):
         return self
 
     def __next__(self):
-        raise NotImplementedError
+        raise NotImplementedError('next')
 
 class FailingMappingKey(object):
     def __getitem__(self, item):
-        raise NotImplementedError
+        raise NotImplementedError('getitem:mappingkey')
 
     def keys(self):
         return list("abcH")
 
 class FailingMapping(object):
     def __getitem__(self):
-        raise NotImplementedError
+        raise NotImplementedError('getitem:mapping')
 
     def keys(self):
-        raise NotImplementedError
+        raise NotImplementedError('keys')
 
 class FailingList(list):
     def __getitem__(self, idx):
         if i == 2:
-            raise NotImplementedError
+            raise NotImplementedError('getitem:list')
         else:
             return super(FailingList, self).__getitem__(idx)
 
+class NoArgsCall(object):
+    def __call__(self):
+        pass
+
+class FailingCall(object):
+    def __call__(self, path):
+        raise NotImplementedError('call')
+
+class FailingNumber(object):
+    def __int__(self):
+        raise NotImplementedError('int')
+
 cb.append("> Output")
 cb.append(">> OutputSetattr")
 ee('del sys.stdout.softspace')
-ee('sys.stdout.softspace = []')
+number_test('sys.stdout.softspace = %s', unsigned=True)
+number_test('sys.stderr.softspace = %s', unsigned=True)
 ee('sys.stdout.attr = None')
 cb.append(">> OutputWrite")
 ee('sys.stdout.write(None)')
@@ -960,18 +983,34 @@
 ee('sys.stdout.writelines([1])')
 iter_test('sys.stdout.writelines(%s)')
 cb.append("> VimCommand")
-ee('vim.command(1)')
+stringtochars_test('vim.command(%s)')
+ee('vim.command("", 2)')
 #! Not checked: vim->python exceptions translating: checked later
 cb.append("> VimToPython")
 #! Not checked: everything: needs errors in internal python functions
 cb.append("> VimEval")
-ee('vim.eval(1)')
+stringtochars_test('vim.eval(%s)')
+ee('vim.eval("", FailingTrue())')
 #! Not checked: everything: needs errors in internal python functions
 cb.append("> VimEvalPy")
-ee('vim.bindeval(1)')
+stringtochars_test('vim.bindeval(%s)')
+ee('vim.eval("", 2)')
 #! Not checked: vim->python exceptions translating: checked later
 cb.append("> VimStrwidth")
-ee('vim.strwidth(1)')
+stringtochars_test('vim.strwidth(%s)')
+cb.append("> VimForeachRTP")
+ee('vim.foreach_rtp(None)')
+ee('vim.foreach_rtp(NoArgsCall())')
+ee('vim.foreach_rtp(FailingCall())')
+ee('vim.foreach_rtp(int, 2)')
+cb.append('> import')
+old_rtp = vim.options['rtp']
+vim.options['rtp'] = os.getcwd().replace(',', '\\,').replace('\\', '\\\\')
+ee('import xxx_no_such_module_xxx')
+ee('import failing_import')
+ee('import failing')
+vim.options['rtp'] = old_rtp
+del old_rtp
 cb.append("> Dictionary")
 cb.append(">> DictionaryConstructor")
 ee('vim.Dictionary("abcI")')
@@ -1050,8 +1089,8 @@
 ee('vim.current.window.buffer = 0')
 ee('vim.current.window.cursor = (100000000, 100000000)')
 ee('vim.current.window.cursor = True')
-ee('vim.current.window.height = "abcK"')
-ee('vim.current.window.width  = "abcL"')
+number_test('vim.current.window.height = %s', unsigned=True)
+number_test('vim.current.window.width = %s', unsigned=True)
 ee('vim.current.window.xxxxxx = True')
 cb.append("> WinList")
 cb.append(">> WinListItem")
@@ -1059,6 +1098,7 @@
 cb.append("> Buffer")
 cb.append(">> StringToLine (indirect)")
 ee('vim.current.buffer[0] = "\\na"')
+ee('vim.current.buffer[0] = b"\\na"')
 cb.append(">> SetBufferLine (indirect)")
 ee('vim.current.buffer[0] = True')
 cb.append(">> SetBufferLineList (indirect)")
@@ -1085,8 +1125,8 @@
 ee('vim.current.buffer.range(1, 2, 3)')
 cb.append("> BufMap")
 cb.append(">> BufMapItem")
-ee('vim.buffers[None]')
 ee('vim.buffers[100000000]')
+number_test('vim.buffers[%s]', natural=True)
 cb.append("> Current")
 cb.append(">> CurrentGetattr")
 ee('vim.current.xxx')
@@ -1110,12 +1150,16 @@
 del convertfrompyobject_test
 del convertfrompymapping_test
 del iter_test
+del number_test
 del FailingTrue
 del FailingIter
 del FailingIterNext
 del FailingMapping
 del FailingMappingKey
 del FailingList
+del NoArgsCall
+del FailingCall
+del FailingNumber
 EOF
 :delfunction F
 :"
@@ -1124,6 +1168,16 @@
 sys.path.insert(0, os.path.join(os.getcwd(), 'python_before'))
 sys.path.append(os.path.join(os.getcwd(), 'python_after'))
 vim.options['rtp'] = os.getcwd().replace(',', '\\,').replace('\\', '\\\\')
+l = []
+def callback(path):
+    l.append(os.path.relpath(path))
+vim.foreach_rtp(callback)
+cb.append(repr(l))
+del l
+def callback(path):
+    return os.path.relpath(path)
+cb.append(repr(vim.foreach_rtp(callback)))
+del callback
 from module import dir as d
 from modulex import ddir
 cb.append(d + ',' + ddir)
@@ -1131,10 +1185,19 @@
 cb.append(before.dir)
 import after
 cb.append(after.dir)
+import topmodule as tm
+import topmodule.submodule as tms
+import topmodule.submodule.subsubmodule.subsubsubmodule as tmsss
+cb.append(tm.__file__[-len('modulex/topmodule/__init__.py'):])
+cb.append(tms.__file__[-len('modulex/topmodule/submodule/__init__.py'):])
+cb.append(tmsss.__file__[-len('modulex/topmodule/submodule/subsubmodule/subsubsubmodule.py'):])
 del before
 del after
 del d
 del ddir
+del tm
+del tms
+del tmsss
 EOF
 :"
 :" Test exceptions
@@ -1188,6 +1251,7 @@
 :call garbagecollect(1)
 :"
 :/^start:/,$wq! test.out
+:" vim: et ts=4 isk-=\:
 :call getchar()
 ENDTEST
 
diff --git a/src/testdir/test87.ok b/src/testdir/test87.ok
index 78b2307..06c97a3 100644
--- a/src/testdir/test87.ok
+++ b/src/testdir/test87.ok
@@ -430,7 +430,16 @@
 > Output
 >> OutputSetattr
 del sys.stdout.softspace:(<class 'AttributeError'>, AttributeError("can't delete OutputObject attributes",))
+>>> Testing NumberToLong using sys.stdout.softspace = %s
 sys.stdout.softspace = []:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got list',))
+sys.stdout.softspace = None:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got NoneType',))
+sys.stdout.softspace = -1:(<class 'ValueError'>, ValueError('number must be greater or equal to zero',))
+<<< Finished
+>>> Testing NumberToLong using sys.stderr.softspace = %s
+sys.stderr.softspace = []:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got list',))
+sys.stderr.softspace = None:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got NoneType',))
+sys.stderr.softspace = -1:(<class 'ValueError'>, ValueError('number must be greater or equal to zero',))
+<<< Finished
 sys.stdout.attr = None:(<class 'AttributeError'>, AttributeError('invalid attribute: attr',))
 >> OutputWrite
 sys.stdout.write(None):(<class 'TypeError'>, TypeError("Can't convert 'NoneType' object to str implicitly",))
@@ -438,24 +447,52 @@
 sys.stdout.writelines(None):(<class 'TypeError'>, TypeError("'NoneType' object is not iterable",))
 sys.stdout.writelines([1]):(<class 'TypeError'>, TypeError("Can't convert 'int' object to str implicitly",))
 >>> Testing *Iter* using sys.stdout.writelines(%s)
-sys.stdout.writelines(FailingIter()):(<class 'NotImplementedError'>, NotImplementedError())
-sys.stdout.writelines(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError())
+sys.stdout.writelines(FailingIter()):(<class 'NotImplementedError'>, NotImplementedError('iter',))
+sys.stdout.writelines(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 > VimCommand
+>>> Testing StringToChars using vim.command(%s)
 vim.command(1):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
+vim.command(b"\0"):(<class 'TypeError'>, TypeError('expected bytes with no null',))
+vim.command("\0"):(<class 'TypeError'>, TypeError('expected bytes with no null',))
+<<< Finished
+vim.command("", 2):(<class 'TypeError'>, TypeError('command() takes exactly one argument (2 given)',))
 > VimToPython
 > VimEval
+>>> Testing StringToChars using vim.eval(%s)
 vim.eval(1):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
+vim.eval(b"\0"):(<class 'TypeError'>, TypeError('expected bytes with no null',))
+vim.eval("\0"):(<class 'TypeError'>, TypeError('expected bytes with no null',))
+<<< Finished
+vim.eval("", FailingTrue()):(<class 'TypeError'>, TypeError('function takes exactly 1 argument (2 given)',))
 > VimEvalPy
+>>> Testing StringToChars using vim.bindeval(%s)
 vim.bindeval(1):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
+vim.bindeval(b"\0"):(<class 'TypeError'>, TypeError('expected bytes with no null',))
+vim.bindeval("\0"):(<class 'TypeError'>, TypeError('expected bytes with no null',))
+<<< Finished
+vim.eval("", 2):(<class 'TypeError'>, TypeError('function takes exactly 1 argument (2 given)',))
 > VimStrwidth
+>>> Testing StringToChars using vim.strwidth(%s)
 vim.strwidth(1):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
+vim.strwidth(b"\0"):(<class 'TypeError'>, TypeError('expected bytes with no null',))
+vim.strwidth("\0"):(<class 'TypeError'>, TypeError('expected bytes with no null',))
+<<< Finished
+> VimForeachRTP
+vim.foreach_rtp(None):(<class 'TypeError'>, TypeError("'NoneType' object is not callable",))
+vim.foreach_rtp(NoArgsCall()):(<class 'TypeError'>, TypeError('__call__() takes exactly 1 positional argument (2 given)',))
+vim.foreach_rtp(FailingCall()):(<class 'NotImplementedError'>, NotImplementedError('call',))
+vim.foreach_rtp(int, 2):(<class 'TypeError'>, TypeError('foreach_rtp() takes exactly one argument (2 given)',))
+> import
+import xxx_no_such_module_xxx:(<class 'ImportError'>, ImportError('No module named xxx_no_such_module_xxx',))
+import failing_import:(<class 'ImportError'>, ImportError('No module named failing_import',))
+import failing:(<class 'ImportError'>, ImportError('No module named failing',))
 > Dictionary
 >> DictionaryConstructor
 vim.Dictionary("abcI"):(<class 'ValueError'>, ValueError('expected sequence element of size 2, but got sequence of size 1',))
 >> DictionarySetattr
 del d.locked:(<class 'AttributeError'>, AttributeError('cannot delete vim.Dictionary attributes',))
-d.locked = FailingTrue():(<class 'NotImplementedError'>, NotImplementedError())
+d.locked = FailingTrue():(<class 'NotImplementedError'>, NotImplementedError('bool',))
 vim.vvars.locked = False:(<class 'TypeError'>, TypeError('cannot modify fixed dictionary',))
 d.scope = True:(<class 'AttributeError'>, AttributeError('cannot set attribute scope',))
 d.xxx = True:(<class 'AttributeError'>, AttributeError('cannot set attribute xxx',))
@@ -494,14 +531,15 @@
 <<< Finished
 >>> Testing *Iter* using d["a"] = {"abcF" : %s}
 d["a"] = {"abcF" : FailingIter()}:(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-d["a"] = {"abcF" : FailingIterNext()}:(<class 'NotImplementedError'>, NotImplementedError())
+d["a"] = {"abcF" : FailingIterNext()}:(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using d["a"] = {"abcF" : %s}
 d["a"] = {"abcF" : None}:(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 d["a"] = {"abcF" : {b"": 1}}:(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 d["a"] = {"abcF" : {"": 1}}:(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-d["a"] = {"abcF" : FailingMapping()}:(<class 'NotImplementedError'>, NotImplementedError())
-d["a"] = {"abcF" : FailingMappingKey()}:(<class 'NotImplementedError'>, NotImplementedError())
+d["a"] = {"abcF" : FailingMapping()}:(<class 'NotImplementedError'>, NotImplementedError('keys',))
+d["a"] = {"abcF" : FailingMappingKey()}:(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+d["a"] = {"abcF" : FailingNumber()}:(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing StringToChars using d["a"] = Mapping({%s : 1})
 d["a"] = Mapping({1 : 1}):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -520,34 +558,36 @@
 <<< Finished
 >>> Testing *Iter* using d["a"] = Mapping({"abcG" : %s})
 d["a"] = Mapping({"abcG" : FailingIter()}):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-d["a"] = Mapping({"abcG" : FailingIterNext()}):(<class 'NotImplementedError'>, NotImplementedError())
+d["a"] = Mapping({"abcG" : FailingIterNext()}):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using d["a"] = Mapping({"abcG" : %s})
 d["a"] = Mapping({"abcG" : None}):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 d["a"] = Mapping({"abcG" : {b"": 1}}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 d["a"] = Mapping({"abcG" : {"": 1}}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-d["a"] = Mapping({"abcG" : FailingMapping()}):(<class 'NotImplementedError'>, NotImplementedError())
-d["a"] = Mapping({"abcG" : FailingMappingKey()}):(<class 'NotImplementedError'>, NotImplementedError())
+d["a"] = Mapping({"abcG" : FailingMapping()}):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+d["a"] = Mapping({"abcG" : FailingMappingKey()}):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+d["a"] = Mapping({"abcG" : FailingNumber()}):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing *Iter* using d["a"] = %s
 d["a"] = FailingIter():(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-d["a"] = FailingIterNext():(<class 'NotImplementedError'>, NotImplementedError())
+d["a"] = FailingIterNext():(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using d["a"] = %s
 d["a"] = None:(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 d["a"] = {b"": 1}:(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 d["a"] = {"": 1}:(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-d["a"] = FailingMapping():(<class 'NotImplementedError'>, NotImplementedError())
-d["a"] = FailingMappingKey():(<class 'NotImplementedError'>, NotImplementedError())
+d["a"] = FailingMapping():(<class 'NotImplementedError'>, NotImplementedError('keys',))
+d["a"] = FailingMappingKey():(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+d["a"] = FailingNumber():(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >> DictionaryUpdate
 >>> kwargs
 >>> iter
-d.update(FailingMapping()):(<class 'NotImplementedError'>, NotImplementedError())
-d.update([FailingIterNext()]):(<class 'NotImplementedError'>, NotImplementedError())
+d.update(FailingMapping()):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+d.update([FailingIterNext()]):(<class 'NotImplementedError'>, NotImplementedError('next',))
 >>> Testing *Iter* using d.update(%s)
-d.update(FailingIter()):(<class 'NotImplementedError'>, NotImplementedError())
-d.update(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError())
+d.update(FailingIter()):(<class 'NotImplementedError'>, NotImplementedError('iter',))
+d.update(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing StringToChars using d.update({%s : 1})
 d.update({1 : 1}):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -566,14 +606,15 @@
 <<< Finished
 >>> Testing *Iter* using d.update({"abcF" : %s})
 d.update({"abcF" : FailingIter()}):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-d.update({"abcF" : FailingIterNext()}):(<class 'NotImplementedError'>, NotImplementedError())
+d.update({"abcF" : FailingIterNext()}):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update({"abcF" : %s})
 d.update({"abcF" : None}):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 d.update({"abcF" : {b"": 1}}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 d.update({"abcF" : {"": 1}}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-d.update({"abcF" : FailingMapping()}):(<class 'NotImplementedError'>, NotImplementedError())
-d.update({"abcF" : FailingMappingKey()}):(<class 'NotImplementedError'>, NotImplementedError())
+d.update({"abcF" : FailingMapping()}):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+d.update({"abcF" : FailingMappingKey()}):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+d.update({"abcF" : FailingNumber()}):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing StringToChars using d.update(Mapping({%s : 1}))
 d.update(Mapping({1 : 1})):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -592,25 +633,27 @@
 <<< Finished
 >>> Testing *Iter* using d.update(Mapping({"abcG" : %s}))
 d.update(Mapping({"abcG" : FailingIter()})):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-d.update(Mapping({"abcG" : FailingIterNext()})):(<class 'NotImplementedError'>, NotImplementedError())
+d.update(Mapping({"abcG" : FailingIterNext()})):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update(Mapping({"abcG" : %s}))
 d.update(Mapping({"abcG" : None})):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 d.update(Mapping({"abcG" : {b"": 1}})):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 d.update(Mapping({"abcG" : {"": 1}})):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-d.update(Mapping({"abcG" : FailingMapping()})):(<class 'NotImplementedError'>, NotImplementedError())
-d.update(Mapping({"abcG" : FailingMappingKey()})):(<class 'NotImplementedError'>, NotImplementedError())
+d.update(Mapping({"abcG" : FailingMapping()})):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+d.update(Mapping({"abcG" : FailingMappingKey()})):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+d.update(Mapping({"abcG" : FailingNumber()})):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing *Iter* using d.update(%s)
-d.update(FailingIter()):(<class 'NotImplementedError'>, NotImplementedError())
-d.update(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError())
+d.update(FailingIter()):(<class 'NotImplementedError'>, NotImplementedError('iter',))
+d.update(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update(%s)
 d.update(None):(<class 'TypeError'>, TypeError("'NoneType' object is not iterable",))
 d.update({b"": 1}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 d.update({"": 1}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-d.update(FailingMapping()):(<class 'NotImplementedError'>, NotImplementedError())
-d.update(FailingMappingKey()):(<class 'NotImplementedError'>, NotImplementedError())
+d.update(FailingMapping()):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+d.update(FailingMappingKey()):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+d.update(FailingNumber()):(<class 'TypeError'>, TypeError("'FailingNumber' object is not iterable",))
 <<< Finished
 >>> Testing StringToChars using d.update(((%s, 0),))
 d.update(((1, 0),)):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -634,14 +677,15 @@
 <<< Finished
 >>> Testing *Iter* using d.update((("a", {"abcF" : %s}),))
 d.update((("a", {"abcF" : FailingIter()}),)):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-d.update((("a", {"abcF" : FailingIterNext()}),)):(<class 'NotImplementedError'>, NotImplementedError())
+d.update((("a", {"abcF" : FailingIterNext()}),)):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update((("a", {"abcF" : %s}),))
 d.update((("a", {"abcF" : None}),)):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 d.update((("a", {"abcF" : {b"": 1}}),)):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 d.update((("a", {"abcF" : {"": 1}}),)):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-d.update((("a", {"abcF" : FailingMapping()}),)):(<class 'NotImplementedError'>, NotImplementedError())
-d.update((("a", {"abcF" : FailingMappingKey()}),)):(<class 'NotImplementedError'>, NotImplementedError())
+d.update((("a", {"abcF" : FailingMapping()}),)):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+d.update((("a", {"abcF" : FailingMappingKey()}),)):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+d.update((("a", {"abcF" : FailingNumber()}),)):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing StringToChars using d.update((("a", Mapping({%s : 1})),))
 d.update((("a", Mapping({1 : 1})),)):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -660,25 +704,27 @@
 <<< Finished
 >>> Testing *Iter* using d.update((("a", Mapping({"abcG" : %s})),))
 d.update((("a", Mapping({"abcG" : FailingIter()})),)):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-d.update((("a", Mapping({"abcG" : FailingIterNext()})),)):(<class 'NotImplementedError'>, NotImplementedError())
+d.update((("a", Mapping({"abcG" : FailingIterNext()})),)):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update((("a", Mapping({"abcG" : %s})),))
 d.update((("a", Mapping({"abcG" : None})),)):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 d.update((("a", Mapping({"abcG" : {b"": 1}})),)):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 d.update((("a", Mapping({"abcG" : {"": 1}})),)):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-d.update((("a", Mapping({"abcG" : FailingMapping()})),)):(<class 'NotImplementedError'>, NotImplementedError())
-d.update((("a", Mapping({"abcG" : FailingMappingKey()})),)):(<class 'NotImplementedError'>, NotImplementedError())
+d.update((("a", Mapping({"abcG" : FailingMapping()})),)):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+d.update((("a", Mapping({"abcG" : FailingMappingKey()})),)):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+d.update((("a", Mapping({"abcG" : FailingNumber()})),)):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing *Iter* using d.update((("a", %s),))
 d.update((("a", FailingIter()),)):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-d.update((("a", FailingIterNext()),)):(<class 'NotImplementedError'>, NotImplementedError())
+d.update((("a", FailingIterNext()),)):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using d.update((("a", %s),))
 d.update((("a", None),)):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 d.update((("a", {b"": 1}),)):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 d.update((("a", {"": 1}),)):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-d.update((("a", FailingMapping()),)):(<class 'NotImplementedError'>, NotImplementedError())
-d.update((("a", FailingMappingKey()),)):(<class 'NotImplementedError'>, NotImplementedError())
+d.update((("a", FailingMapping()),)):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+d.update((("a", FailingMappingKey()),)):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+d.update((("a", FailingNumber()),)):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >> DictionaryPopItem
 d.popitem(1, 2):(<class 'TypeError'>, TypeError('popitem() takes no arguments (2 given)',))
@@ -689,8 +735,8 @@
 vim.List(1, 2):(<class 'TypeError'>, TypeError('function takes at most 1 argument (2 given)',))
 vim.List(a=1):(<class 'TypeError'>, TypeError('list constructor does not accept keyword arguments',))
 >>> Testing *Iter* using vim.List(%s)
-vim.List(FailingIter()):(<class 'NotImplementedError'>, NotImplementedError())
-vim.List(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError())
+vim.List(FailingIter()):(<class 'NotImplementedError'>, NotImplementedError('iter',))
+vim.List(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing StringToChars using vim.List([{%s : 1}])
 vim.List([{1 : 1}]):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -709,14 +755,15 @@
 <<< Finished
 >>> Testing *Iter* using vim.List([{"abcF" : %s}])
 vim.List([{"abcF" : FailingIter()}]):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-vim.List([{"abcF" : FailingIterNext()}]):(<class 'NotImplementedError'>, NotImplementedError())
+vim.List([{"abcF" : FailingIterNext()}]):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using vim.List([{"abcF" : %s}])
 vim.List([{"abcF" : None}]):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 vim.List([{"abcF" : {b"": 1}}]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 vim.List([{"abcF" : {"": 1}}]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-vim.List([{"abcF" : FailingMapping()}]):(<class 'NotImplementedError'>, NotImplementedError())
-vim.List([{"abcF" : FailingMappingKey()}]):(<class 'NotImplementedError'>, NotImplementedError())
+vim.List([{"abcF" : FailingMapping()}]):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+vim.List([{"abcF" : FailingMappingKey()}]):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+vim.List([{"abcF" : FailingNumber()}]):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing StringToChars using vim.List([Mapping({%s : 1})])
 vim.List([Mapping({1 : 1})]):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -735,25 +782,27 @@
 <<< Finished
 >>> Testing *Iter* using vim.List([Mapping({"abcG" : %s})])
 vim.List([Mapping({"abcG" : FailingIter()})]):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-vim.List([Mapping({"abcG" : FailingIterNext()})]):(<class 'NotImplementedError'>, NotImplementedError())
+vim.List([Mapping({"abcG" : FailingIterNext()})]):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using vim.List([Mapping({"abcG" : %s})])
 vim.List([Mapping({"abcG" : None})]):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 vim.List([Mapping({"abcG" : {b"": 1}})]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 vim.List([Mapping({"abcG" : {"": 1}})]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-vim.List([Mapping({"abcG" : FailingMapping()})]):(<class 'NotImplementedError'>, NotImplementedError())
-vim.List([Mapping({"abcG" : FailingMappingKey()})]):(<class 'NotImplementedError'>, NotImplementedError())
+vim.List([Mapping({"abcG" : FailingMapping()})]):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+vim.List([Mapping({"abcG" : FailingMappingKey()})]):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+vim.List([Mapping({"abcG" : FailingNumber()})]):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing *Iter* using vim.List([%s])
 vim.List([FailingIter()]):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-vim.List([FailingIterNext()]):(<class 'NotImplementedError'>, NotImplementedError())
+vim.List([FailingIterNext()]):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using vim.List([%s])
 vim.List([None]):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 vim.List([{b"": 1}]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 vim.List([{"": 1}]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-vim.List([FailingMapping()]):(<class 'NotImplementedError'>, NotImplementedError())
-vim.List([FailingMappingKey()]):(<class 'NotImplementedError'>, NotImplementedError())
+vim.List([FailingMapping()]):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+vim.List([FailingMappingKey()]):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+vim.List([FailingNumber()]):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >> ListItem
 l[1000]:(<class 'IndexError'>, IndexError('list index out of range',))
@@ -763,8 +812,8 @@
 >> ListAssSlice
 ll[1:100] = "abcJ":(<class 'vim.error'>, error('list is locked',))
 >>> Testing *Iter* using l[:] = %s
-l[:] = FailingIter():(<class 'NotImplementedError'>, NotImplementedError())
-l[:] = FailingIterNext()::(<class 'NotImplementedError'>, NotImplementedError())
+l[:] = FailingIter():(<class 'NotImplementedError'>, NotImplementedError('iter',))
+l[:] = FailingIterNext():(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing StringToChars using l[:] = [{%s : 1}]
 l[:] = [{1 : 1}]:(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -783,14 +832,15 @@
 <<< Finished
 >>> Testing *Iter* using l[:] = [{"abcF" : %s}]
 l[:] = [{"abcF" : FailingIter()}]:(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-l[:] = [{"abcF" : FailingIterNext()}]:(<class 'NotImplementedError'>, NotImplementedError())
+l[:] = [{"abcF" : FailingIterNext()}]:(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using l[:] = [{"abcF" : %s}]
 l[:] = [{"abcF" : None}]:(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 l[:] = [{"abcF" : {b"": 1}}]:(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 l[:] = [{"abcF" : {"": 1}}]:(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-l[:] = [{"abcF" : FailingMapping()}]:(<class 'NotImplementedError'>, NotImplementedError())
-l[:] = [{"abcF" : FailingMappingKey()}]:(<class 'NotImplementedError'>, NotImplementedError())
+l[:] = [{"abcF" : FailingMapping()}]:(<class 'NotImplementedError'>, NotImplementedError('keys',))
+l[:] = [{"abcF" : FailingMappingKey()}]:(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+l[:] = [{"abcF" : FailingNumber()}]:(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing StringToChars using l[:] = [Mapping({%s : 1})]
 l[:] = [Mapping({1 : 1})]:(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -809,30 +859,32 @@
 <<< Finished
 >>> Testing *Iter* using l[:] = [Mapping({"abcG" : %s})]
 l[:] = [Mapping({"abcG" : FailingIter()})]:(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-l[:] = [Mapping({"abcG" : FailingIterNext()})]:(<class 'NotImplementedError'>, NotImplementedError())
+l[:] = [Mapping({"abcG" : FailingIterNext()})]:(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using l[:] = [Mapping({"abcG" : %s})]
 l[:] = [Mapping({"abcG" : None})]:(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 l[:] = [Mapping({"abcG" : {b"": 1}})]:(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 l[:] = [Mapping({"abcG" : {"": 1}})]:(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-l[:] = [Mapping({"abcG" : FailingMapping()})]:(<class 'NotImplementedError'>, NotImplementedError())
-l[:] = [Mapping({"abcG" : FailingMappingKey()})]:(<class 'NotImplementedError'>, NotImplementedError())
+l[:] = [Mapping({"abcG" : FailingMapping()})]:(<class 'NotImplementedError'>, NotImplementedError('keys',))
+l[:] = [Mapping({"abcG" : FailingMappingKey()})]:(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+l[:] = [Mapping({"abcG" : FailingNumber()})]:(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing *Iter* using l[:] = [%s]
 l[:] = [FailingIter()]:(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-l[:] = [FailingIterNext()]:(<class 'NotImplementedError'>, NotImplementedError())
+l[:] = [FailingIterNext()]:(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using l[:] = [%s]
 l[:] = [None]:(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 l[:] = [{b"": 1}]:(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 l[:] = [{"": 1}]:(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-l[:] = [FailingMapping()]:(<class 'NotImplementedError'>, NotImplementedError())
-l[:] = [FailingMappingKey()]:(<class 'NotImplementedError'>, NotImplementedError())
+l[:] = [FailingMapping()]:(<class 'NotImplementedError'>, NotImplementedError('keys',))
+l[:] = [FailingMappingKey()]:(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+l[:] = [FailingNumber()]:(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >> ListConcatInPlace
 >>> Testing *Iter* using l.extend(%s)
-l.extend(FailingIter()):(<class 'NotImplementedError'>, NotImplementedError())
-l.extend(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError())
+l.extend(FailingIter()):(<class 'NotImplementedError'>, NotImplementedError('iter',))
+l.extend(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing StringToChars using l.extend([{%s : 1}])
 l.extend([{1 : 1}]):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -851,14 +903,15 @@
 <<< Finished
 >>> Testing *Iter* using l.extend([{"abcF" : %s}])
 l.extend([{"abcF" : FailingIter()}]):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-l.extend([{"abcF" : FailingIterNext()}]):(<class 'NotImplementedError'>, NotImplementedError())
+l.extend([{"abcF" : FailingIterNext()}]):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using l.extend([{"abcF" : %s}])
 l.extend([{"abcF" : None}]):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 l.extend([{"abcF" : {b"": 1}}]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 l.extend([{"abcF" : {"": 1}}]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-l.extend([{"abcF" : FailingMapping()}]):(<class 'NotImplementedError'>, NotImplementedError())
-l.extend([{"abcF" : FailingMappingKey()}]):(<class 'NotImplementedError'>, NotImplementedError())
+l.extend([{"abcF" : FailingMapping()}]):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+l.extend([{"abcF" : FailingMappingKey()}]):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+l.extend([{"abcF" : FailingNumber()}]):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing StringToChars using l.extend([Mapping({%s : 1})])
 l.extend([Mapping({1 : 1})]):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -877,29 +930,31 @@
 <<< Finished
 >>> Testing *Iter* using l.extend([Mapping({"abcG" : %s})])
 l.extend([Mapping({"abcG" : FailingIter()})]):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-l.extend([Mapping({"abcG" : FailingIterNext()})]):(<class 'NotImplementedError'>, NotImplementedError())
+l.extend([Mapping({"abcG" : FailingIterNext()})]):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using l.extend([Mapping({"abcG" : %s})])
 l.extend([Mapping({"abcG" : None})]):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 l.extend([Mapping({"abcG" : {b"": 1}})]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 l.extend([Mapping({"abcG" : {"": 1}})]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-l.extend([Mapping({"abcG" : FailingMapping()})]):(<class 'NotImplementedError'>, NotImplementedError())
-l.extend([Mapping({"abcG" : FailingMappingKey()})]):(<class 'NotImplementedError'>, NotImplementedError())
+l.extend([Mapping({"abcG" : FailingMapping()})]):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+l.extend([Mapping({"abcG" : FailingMappingKey()})]):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+l.extend([Mapping({"abcG" : FailingNumber()})]):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing *Iter* using l.extend([%s])
 l.extend([FailingIter()]):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-l.extend([FailingIterNext()]):(<class 'NotImplementedError'>, NotImplementedError())
+l.extend([FailingIterNext()]):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using l.extend([%s])
 l.extend([None]):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 l.extend([{b"": 1}]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 l.extend([{"": 1}]):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-l.extend([FailingMapping()]):(<class 'NotImplementedError'>, NotImplementedError())
-l.extend([FailingMappingKey()]):(<class 'NotImplementedError'>, NotImplementedError())
+l.extend([FailingMapping()]):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+l.extend([FailingMappingKey()]):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+l.extend([FailingNumber()]):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >> ListSetattr
 del l.locked:(<class 'AttributeError'>, AttributeError('cannot delete vim.List attributes',))
-l.locked = FailingTrue():(<class 'NotImplementedError'>, NotImplementedError())
+l.locked = FailingTrue():(<class 'NotImplementedError'>, NotImplementedError('bool',))
 l.xxx = True:(<class 'AttributeError'>, AttributeError('cannot set attribute xxx',))
 > Function
 >> FunctionConstructor
@@ -924,14 +979,15 @@
 <<< Finished
 >>> Testing *Iter* using f({"abcF" : %s})
 f({"abcF" : FailingIter()}):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-f({"abcF" : FailingIterNext()}):(<class 'NotImplementedError'>, NotImplementedError())
+f({"abcF" : FailingIterNext()}):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using f({"abcF" : %s})
 f({"abcF" : None}):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 f({"abcF" : {b"": 1}}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 f({"abcF" : {"": 1}}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-f({"abcF" : FailingMapping()}):(<class 'NotImplementedError'>, NotImplementedError())
-f({"abcF" : FailingMappingKey()}):(<class 'NotImplementedError'>, NotImplementedError())
+f({"abcF" : FailingMapping()}):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+f({"abcF" : FailingMappingKey()}):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+f({"abcF" : FailingNumber()}):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing StringToChars using f(Mapping({%s : 1}))
 f(Mapping({1 : 1})):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -950,25 +1006,27 @@
 <<< Finished
 >>> Testing *Iter* using f(Mapping({"abcG" : %s}))
 f(Mapping({"abcG" : FailingIter()})):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-f(Mapping({"abcG" : FailingIterNext()})):(<class 'NotImplementedError'>, NotImplementedError())
+f(Mapping({"abcG" : FailingIterNext()})):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using f(Mapping({"abcG" : %s}))
 f(Mapping({"abcG" : None})):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 f(Mapping({"abcG" : {b"": 1}})):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 f(Mapping({"abcG" : {"": 1}})):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-f(Mapping({"abcG" : FailingMapping()})):(<class 'NotImplementedError'>, NotImplementedError())
-f(Mapping({"abcG" : FailingMappingKey()})):(<class 'NotImplementedError'>, NotImplementedError())
+f(Mapping({"abcG" : FailingMapping()})):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+f(Mapping({"abcG" : FailingMappingKey()})):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+f(Mapping({"abcG" : FailingNumber()})):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing *Iter* using f(%s)
 f(FailingIter()):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-f(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError())
+f(FailingIterNext()):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using f(%s)
 f(None):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 f({b"": 1}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 f({"": 1}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-f(FailingMapping()):(<class 'NotImplementedError'>, NotImplementedError())
-f(FailingMappingKey()):(<class 'NotImplementedError'>, NotImplementedError())
+f(FailingMapping()):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+f(FailingMappingKey()):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+f(FailingNumber()):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing StringToChars using fd(self={%s : 1})
 fd(self={1 : 1}):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -987,14 +1045,15 @@
 <<< Finished
 >>> Testing *Iter* using fd(self={"abcF" : %s})
 fd(self={"abcF" : FailingIter()}):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-fd(self={"abcF" : FailingIterNext()}):(<class 'NotImplementedError'>, NotImplementedError())
+fd(self={"abcF" : FailingIterNext()}):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using fd(self={"abcF" : %s})
 fd(self={"abcF" : None}):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 fd(self={"abcF" : {b"": 1}}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 fd(self={"abcF" : {"": 1}}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-fd(self={"abcF" : FailingMapping()}):(<class 'NotImplementedError'>, NotImplementedError())
-fd(self={"abcF" : FailingMappingKey()}):(<class 'NotImplementedError'>, NotImplementedError())
+fd(self={"abcF" : FailingMapping()}):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+fd(self={"abcF" : FailingMappingKey()}):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+fd(self={"abcF" : FailingNumber()}):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing StringToChars using fd(self=Mapping({%s : 1}))
 fd(self=Mapping({1 : 1})):(<class 'TypeError'>, TypeError('expected bytes() or str() instance, but got int',))
@@ -1013,14 +1072,15 @@
 <<< Finished
 >>> Testing *Iter* using fd(self=Mapping({"abcG" : %s}))
 fd(self=Mapping({"abcG" : FailingIter()})):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim structure',))
-fd(self=Mapping({"abcG" : FailingIterNext()})):(<class 'NotImplementedError'>, NotImplementedError())
+fd(self=Mapping({"abcG" : FailingIterNext()})):(<class 'NotImplementedError'>, NotImplementedError('next',))
 <<< Finished
 >>> Testing ConvertFromPyObject using fd(self=Mapping({"abcG" : %s}))
 fd(self=Mapping({"abcG" : None})):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim structure',))
 fd(self=Mapping({"abcG" : {b"": 1}})):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 fd(self=Mapping({"abcG" : {"": 1}})):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-fd(self=Mapping({"abcG" : FailingMapping()})):(<class 'NotImplementedError'>, NotImplementedError())
-fd(self=Mapping({"abcG" : FailingMappingKey()})):(<class 'NotImplementedError'>, NotImplementedError())
+fd(self=Mapping({"abcG" : FailingMapping()})):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+fd(self=Mapping({"abcG" : FailingMappingKey()})):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+fd(self=Mapping({"abcG" : FailingNumber()})):(<class 'NotImplementedError'>, NotImplementedError('int',))
 <<< Finished
 >>> Testing *Iter* using fd(self=%s)
 fd(self=FailingIter()):(<class 'TypeError'>, TypeError('unable to convert FailingIter to vim dictionary',))
@@ -1030,8 +1090,9 @@
 fd(self=None):(<class 'TypeError'>, TypeError('unable to convert NoneType to vim dictionary',))
 fd(self={b"": 1}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
 fd(self={"": 1}):(<class 'ValueError'>, ValueError('empty keys are not allowed',))
-fd(self=FailingMapping()):(<class 'NotImplementedError'>, NotImplementedError())
-fd(self=FailingMappingKey()):(<class 'NotImplementedError'>, NotImplementedError())
+fd(self=FailingMapping()):(<class 'NotImplementedError'>, NotImplementedError('keys',))
+fd(self=FailingMappingKey()):(<class 'NotImplementedError'>, NotImplementedError('getitem:mappingkey',))
+fd(self=FailingNumber()):(<class 'TypeError'>, TypeError('unable to convert FailingNumber to vim dictionary',))
 <<< Finished
 >>> Testing ConvertFromPyMapping using fd(self=%s)
 fd(self=[]):(<class 'AttributeError'>, AttributeError('keys',))
@@ -1049,8 +1110,16 @@
 vim.current.window.buffer = 0:(<class 'TypeError'>, TypeError('readonly attribute: buffer',))
 vim.current.window.cursor = (100000000, 100000000):(<class 'vim.error'>, error('cursor position outside buffer',))
 vim.current.window.cursor = True:(<class 'TypeError'>, TypeError('argument must be 2-item sequence, not bool',))
-vim.current.window.height = "abcK":(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got str',))
-vim.current.window.width  = "abcL":(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got str',))
+>>> Testing NumberToLong using vim.current.window.height = %s
+vim.current.window.height = []:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got list',))
+vim.current.window.height = None:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got NoneType',))
+vim.current.window.height = -1:(<class 'ValueError'>, ValueError('number must be greater or equal to zero',))
+<<< Finished
+>>> Testing NumberToLong using vim.current.window.width = %s
+vim.current.window.width = []:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got list',))
+vim.current.window.width = None:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got NoneType',))
+vim.current.window.width = -1:(<class 'ValueError'>, ValueError('number must be greater or equal to zero',))
+<<< Finished
 vim.current.window.xxxxxx = True:(<class 'AttributeError'>, AttributeError('xxxxxx',))
 > WinList
 >> WinListItem
@@ -1058,6 +1127,7 @@
 > Buffer
 >> StringToLine (indirect)
 vim.current.buffer[0] = "\na":(<class 'vim.error'>, error('string cannot contain newlines',))
+vim.current.buffer[0] = b"\na":(<class 'vim.error'>, error('string cannot contain newlines',))
 >> SetBufferLine (indirect)
 vim.current.buffer[0] = True:(<class 'TypeError'>, TypeError('bad argument type for built-in operation',))
 >> SetBufferLineList (indirect)
@@ -1084,8 +1154,13 @@
 vim.current.buffer.range(1, 2, 3):(<class 'TypeError'>, TypeError('function takes exactly 2 arguments (3 given)',))
 > BufMap
 >> BufMapItem
-vim.buffers[None]:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got NoneType',))
 vim.buffers[100000000]:(<class 'KeyError'>, KeyError(100000000,))
+>>> Testing NumberToLong using vim.buffers[%s]
+vim.buffers[[]]:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got list',))
+vim.buffers[None]:(<class 'TypeError'>, TypeError('expected int() or something supporting coercing to int(), but got NoneType',))
+vim.buffers[-1]:(<class 'ValueError'>, ValueError('number must be greater then zero',))
+vim.buffers[0]:(<class 'ValueError'>, ValueError('number must be greater then zero',))
+<<< Finished
 > Current
 >> CurrentGetattr
 vim.current.xxx:(<class 'AttributeError'>, AttributeError("'vim.currentdata' object has no attribute 'xxx'",))
@@ -1095,9 +1170,14 @@
 vim.current.window = True:(<class 'TypeError'>, TypeError('expected vim.Window object, but got bool',))
 vim.current.tabpage = True:(<class 'TypeError'>, TypeError('expected vim.TabPage object, but got bool',))
 vim.current.xxx = True:(<class 'AttributeError'>, AttributeError('xxx',))
+['.']
+'.'
 3,xx
 before
 after
+pythonx/topmodule/__init__.py
+pythonx/topmodule/submodule/__init__.py
+pythonx/topmodule/submodule/subsubmodule/subsubsubmodule.py
 vim.command("throw 'abcN'"):(<class 'vim.error'>, error('abcN',))
 Exe("throw 'def'"):(<class 'vim.error'>, error('def',))
 vim.eval("Exe('throw ''ghi''')"):(<class 'vim.error'>, error('ghi',))
diff --git a/src/version.c b/src/version.c
index 2f24c3f..69603fb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -729,6 +729,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1236,
+/**/
     1235,
 /**/
     1234,