From 7541fa63d1546f1a434ec742627d9632dd751959 Mon Sep 17 00:00:00 2001
From: Linus Nordberg <linus@nordu.net>
Date: Sat, 26 Apr 2014 20:38:48 +0200
Subject: Fix bug with adding first element of empty tree.

And tests!
---
 src/ht.erl | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

(limited to 'src/ht.erl')

diff --git a/src/ht.erl b/src/ht.erl
index 2edee82..8b71628 100644
--- a/src/ht.erl
+++ b/src/ht.erl
@@ -54,7 +54,7 @@ size(Head) ->
 %% Example: N=6 (110) => l=1, the last and rightmost inner node.
 -spec append(head(), leaf() | iolist() | binary()) -> head().
 append(#head{version = 0}, Leaf) when is_record(Leaf, leaf) ->
-    mkhead(0, Leaf);
+    mkhead(1, Leaf);
 append(Head, Leaf) when is_record(Leaf, leaf) ->
     N = Head#head.version,
     %Depth = depth(Head),
@@ -167,8 +167,9 @@ rightbranchdepth(Tree, Acc) ->
 %%%%%%%%%%%%%%%%%%%%
 %% Internal tests.
 -define(TEST_VECTOR_TREES,
-        [<<148,242,40,0,3,172,180,106,111,230,146,161,32,40,128,38,103,8,194,
-           102,72,68, 126,70,108,47,8,216,208,146,178,107>>]).
+        [[<<"a foo is a bar">>,
+          <<148,242,40,0,3,172,180,106,111,230,146,161,32,40,128,38,103,8,194,
+           102,72,68, 126,70,108,47,8,216,208,146,178,107>>]]).
 %% Test vectors from certificate-transparency/src/python/ct/crypto/merkle_test.py.
 -define(EMPTY_HASH, "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855").
 -define(TEST_VECTOR_LEAVES, ["", "\x00", "\x10", " !", "01", "@ABC", "PQRSTUVW", "`abcdefghijklmno"]).
@@ -185,11 +186,12 @@ basic_helpers_test_() ->
     [test_bitcount()].
 
 basic_tree_test_() ->
-    TestVectorTree = #leaf{hash = hd(?TEST_VECTOR_TREES)},
+    TVT1 = lists:nth(1, ?TEST_VECTOR_TREES),
     [?_assertEqual(#head{version = 0, tree = undefined},
                    create()),
-     ?_assertEqual(#head{version = 1, tree = TestVectorTree},
-                   create("a foo is a bar"))].
+     ?_assertEqual(#head{version = 1,
+                         tree = #leaf{hash = lists:last(TVT1)}},
+                   create(hd(TVT1)))].
 
 empty_hash_test_() ->
     [?_assertEqual(hex:hexstr_to_bin(?EMPTY_HASH), mth([]))].
@@ -202,6 +204,15 @@ mth_test() ->
       end,
       lists:seq(1, length(?TEST_VECTOR_LEAVES))).
 
+new_tree_test_() ->
+    TVT1 = lists:nth(1, ?TEST_VECTOR_TREES),
+    V0 = create(),
+    V1 = append(V0, hd(TVT1)),
+    [?_assertEqual(0, V0#head.version),
+     ?_assertEqual(undefined, V0#head.tree),
+     ?_assertEqual(lists:last(TVT1), (V1#head.tree)#leaf.hash),
+     ?_assertEqual(1, V1#head.version)].
+
 %% @doc Build trees using append/2 and mth/2 and compare the resulting
 %% tree hashes.
 append_test() ->
-- 
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