Fix couch_key_tree_tests.erloptimize-doc-updates

The `should_merge_tree_to_itself` and `should_merge_tree_of_odd_length`
tests were both invalid as merging does not support merging of anything
other than a linear path. This failure was covered up by the fact that
the stem operation will detect and cover up any errors from a failed
merge.

Co-Authored-By: Nick Vatamaniuc <vatamane@apache.org>

1 files changed, 19 insertions, 5 deletions

diff --git a/src/couch/test/couch_key_tree_tests.erl b/src/couch/test/couch_key_tree_tests.erl
index 88d920363..2b7d5fe62 100644
--- a/src/couch/test/couch_key_tree_tests.erl
+++ b/src/couch/test/couch_key_tree_tests.erl
@@ -167,8 +167,23 @@ should_merge_reflexive_for_child_nodes()->
 should_merge_tree_to_itself()->
     TwoChildSibs = {1, {"1","foo", [{"1a", "bar", []},
                                     {"1b", "bar", []}]}},
-    ?_assertEqual({[TwoChildSibs], new_branch},
-                  couch_key_tree:merge([TwoChildSibs], TwoChildSibs, ?DEPTH)).
+    Leafs = couch_key_tree:get_all_leafs([TwoChildSibs]),
+    Paths = lists:map(fun leaf_to_path/1, Leafs),
+    FinalTree = lists:foldl(fun(Path, TreeAcc) ->
+        {NewTree, internal_node} = couch_key_tree:merge(TreeAcc, Path),
+        NewTree
+    end, [TwoChildSibs], Paths),
+    ?_assertEqual([TwoChildSibs], FinalTree).
+
+leaf_to_path({Value, {Start, Keys}}) ->
+    [Branch] = to_branch(Value, lists:reverse(Keys)),
+    {Start - length(Keys) + 1, Branch}.
+
+to_branch(Value, [Key]) ->
+    [{Key, Value, []}];
+to_branch(Value, [Key | RestKeys]) ->
+    [{Key, [], to_branch(Value, RestKeys)}].
+
 
 should_merge_tree_of_odd_length()->
     TwoChild = {1, {"1","foo", [{"1a", "bar", [{"1aa", "bar", []}]}]}},
@@ -176,9 +191,8 @@ should_merge_tree_of_odd_length()->
                                     {"1b", "bar", []}]}},
     TwoChildPlusSibs = {1, {"1","foo", [{"1a", "bar", [{"1aa", "bar", []}]},
                                         {"1b", "bar", []}]}},
-
-    ?_assertEqual({[TwoChildPlusSibs], new_branch},
-                  couch_key_tree:merge([TwoChild], TwoChildSibs, ?DEPTH)).
+    ?_assertEqual({[TwoChildPlusSibs], new_leaf},
+                  couch_key_tree:merge([TwoChildSibs], TwoChild, ?DEPTH)).
 
 should_merge_tree_with_stem()->
     Stemmed = {2, {"1a", "bar", []}},