Comment 1 for bug 315775

zope.app.container.btree.BTreeContainer is not inheriting from ZODB BTrees directly. In order to access the real btree data container, we have to go through the data container attribute (_SampleContainer__data). The BTree data container is a pure C object, it doesn't provide/implement anything, therefore it's impossible to test it against an interface.

I have a code working, with tests, for the "clear" method. The problem is : we would rely purely on the zope.container implementation and it's not good. Even more, zope.container.btree doesn't provide an object implementing a Btrees.Interfaces interface. Maybe we should make zope.container at least implementing Btrees.Interfaces.ICollection ? If not, we could, in Grok, provide a clean implementation that does really provide what we are expecting : a real BTrees.IBTree.