Merge pull request #3173 from jtpio/close-all

Fix the use of _active_widgets in Widget.close_all()

ipywidgets/widgets/tests/test_widget.py

@@ -43,3 +43,15 @@ def test_widget_view():
     assert 'application/vnd.jupyter.widget-view+json' in mime_bundle, "widget should have have a view"
     assert cap.stdout == '', repr(cap.stdout)
     assert cap.stderr == '', repr(cap.stderr)
+
+
+def test_close_all():
+    # create a couple of widgets
+    widgets = [Button() for i in range(10)]
+
+    assert len(Widget._active_widgets) > 0, "expect active widgets"
+
+    # close all the widgets
+    Widget.close_all()
+
+    assert len(Widget._active_widgets) == 0, "active widgets should be cleared"

ipywidgets/widgets/widget.py

@@ -271,7 +271,7 @@ class Widget(LoggingHasTraits):
 
     @classmethod
     def close_all(cls):
-        for widget in list(cls.widgets.values()):
+        for widget in list(cls._active_widgets.values()):
             widget.close()