.

wcfs/internal/xbtree.py

@@ -38,7 +38,7 @@ class Tree:
     #   .keyv       () of keys
     #   .children   () of children  len(.children) == len(.keyv) + 1
     def __init__(t, keyv, *children):
-        assert len(children) == len(keyv) + 1, (keyv, children)
+        assert len(children) == len(keyv) + 1, (keyv, children) # XXX empty tree
         # XXX assert keyv ↑
         # XXX assert children keys consistent?
         # XXX assert all children are of the same type

wcfs/internal/xbtree_test.py

@@ -29,7 +29,7 @@ def test_topologyOf():
 
     # XXX 1 k->v
 
-    # XXX known degenerate topology
+    # known degenerate topology, see:
     # https://github.com/zopefoundation/ZODB/commit/6cd24e99f89b
     # https://github.com/zopefoundation/BTrees/blob/4.7.2-1-g078ba60/BTrees/tests/testBTrees.py#L20
     t, keys = testBTrees.DegenerateBTree("testBasicOps")._build_degenerate_tree()