fix and test inheritance of CompundWidgets (#130)

* fix and test inheritance of CompundWidgets

* on pypy2.7, new version of soupsieve fails.

setup.py

@@ -65,6 +65,9 @@ def get_description(fname='README.rst'):
     _extra_kajiki + \
     _extra_chameleon
 
+if sys.version_info[0] == 2 and sys.version_info[1] == 7:
+    tests_require.append('soupsieve<2.0')
+
 if sys.version_info[0] == 2 and sys.version_info[1] <= 6:
     tests_require.append('WebTest<2.0.0')
 else:

tests/test_hierarchy.py

@@ -88,7 +88,32 @@ class A:
         assert(test.children.b.value == 10)
         assert(test.children.c.value == 20)
 
-
+    def test_cw_duplicate(self):
+        try:
+            class Parent(twc.CompoundWidget):
+                class Left(twc.CompoundWidget):
+                    id = None
+                    c = twc.Widget()
+
+                class Right(twc.CompoundWidget):
+                    id = None
+                    c = twc.Widget()
+            assert False, 'Must raise'
+        except twc.WidgetError as ex:
+            assert "Duplicate id 'c'" in str(ex)
+
+    def test_cw_override(self):
+        class Grandpa(twc.CompoundWidget):
+            class Parent(twc.CompoundWidget):
+                a = twc.Widget(id='a', name='override_me')
+
+            class Child(Parent):
+                a = twc.Widget(id='a', name='A')
+                b = twc.Widget(id='b', name='B')
+        assert len(Grandpa.children.Child.children) == 2
+        assert Grandpa.children.Child.children[0].name == 'A'
+        assert Grandpa.children.Child.children[1].name == 'B'
+
     #--
     # Repeating Widget Bunch
     #--

tw2/core/widgets.py

@@ -590,8 +590,12 @@ def post_define(cls):
         cls._sub_compound = not getattr(cls, 'id', None)
         if not hasattr(cls, 'children'):
             return
-        joined_cld = []
 
+        super_children_ids = []
+        if hasattr(super(cls, cls), 'children'):
+            super_children_ids = [c.id for c in super(cls, cls).children if hasattr(c, 'id')]
+
+        joined_cld = []
         for c in cls.children:
             if not isinstance(c, type) or not issubclass(c, Widget):
                 raise pm.ParameterError("All children must be widgets")
@@ -601,7 +605,9 @@ def post_define(cls):
         for c in cls.children_deep():
             if getattr(c, 'id', None):
                 if c.id in ids:
-                    raise core.WidgetError("Duplicate id '%s'" % c.id)
+                    if c.id not in super_children_ids:
+                        raise core.WidgetError("Duplicate id '%s'" % c.id)
+                    joined_cld.pop([x.id for x in joined_cld].index(c.id))
                 ids.add(c.id)
         cls.children = WidgetBunch(joined_cld)
         cls.keyed_children = [