Support for plone.app.widgets RichText widget.

[maethu]

@jone What is the best practice for writing a test in this case?

• Installing p.a.widgets? (AND all its depts.)
• Mock a widget?
• ??

[jone]

I would not add a dependency to p.a.widgets, because it makes maintenance much more complicated because of its dependencies. I'd kind of mock it, like the z3c choice collection widget is done (see https://github.com/4teamwork/ftw.testbrowser/blob/master/ftw/testbrowser/tests/test_widgets_z3c_choice_collection.py).

[jone]

update or drop?