.

wcfs/internal/xbtree_test.py

@@ -443,6 +443,11 @@ def test_restructure():
             assert ztree[k] == v
 
 
+    # S returns topo-encoded structure of ztree
+    def S(ztree):
+        return xbtree.TopoEncode(xbtree.StructureOf(ztree))
+
+
     # Z0 creates new empty tree
     def Z0():
         z = Z()
@@ -569,7 +574,10 @@ def test_restructure():
     assert crack_bucket(b13) == ([1,3], [X[1], X[3]])
 
 
-    # XXX tree with one committed bucket
+    # add 1 key -> B splits -> B + B
+    assert S(z) == 'T/B1,3'
+    z[5] = X[5]
+    assert S(z) == 'T3/B1-B3,5'
 
     # XXX tree with 2 buckets