extensions/browser/content_hash_tree_unittest.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/memory/scoped_ptr.h"
   6 #include "base/stl_util.h"
   7 #include "crypto/secure_hash.h"
   8 #include "crypto/sha2.h"
   9 #include "extensions/browser/content_hash_tree.h"
  10 #include "testing/gtest/include/gtest/gtest.h"
  11
  12 using crypto::kSHA256Length;
  13 using crypto::SecureHash;
  14
  15 // Helper to return a fake sha256 signature based on a seed.
  16 static std::string FakeSignatureWithSeed(int seed) {
  17   std::string input;
  18   for (int i = 0; i < seed * 3; i++) {
  19     input.push_back(static_cast<char>(((i + 19) * seed) % 256));
  20   }
  21   return crypto::SHA256HashString(input);
  22 }
  23
  24 namespace extensions {
  25
  26 TEST(ContentHashTreeTest, HashTreeBasics) {
  27   std::vector<std::string> nodes;
  28   // Empty array.
  29   EXPECT_EQ(std::string(), ComputeTreeHashRoot(nodes, 16));
  30
  31   // One node.
  32   std::string node1 = FakeSignatureWithSeed(1);
  33   nodes.push_back(node1);
  34   EXPECT_EQ(node1, ComputeTreeHashRoot(nodes, 16));
  35
  36   // Two nodes.
  37   std::string node2 = FakeSignatureWithSeed(2);
  38   nodes.push_back(node2);
  39
  40   std::string expected(kSHA256Length, 0);
  41   scoped_ptr<SecureHash> hash(SecureHash::Create(SecureHash::SHA256));
  42   hash->Update(node1.data(), node1.size());
  43   hash->Update(node2.data(), node2.size());
  44   hash->Finish(string_as_array(&expected), expected.size());
  45   EXPECT_EQ(expected, ComputeTreeHashRoot(nodes, 16));
  46 }
  47
  48 TEST(ContentHashTreeTest, HashTreeMultipleLevels) {
  49   std::vector<std::string> nodes;
  50   for (int i = 0; i < 3; i++) {
  51     std::string node;
  52     nodes.push_back(FakeSignatureWithSeed(i));
  53   }
  54
  55   // First try a test where our branch factor is >= 3, so we expect the result
  56   // to be the hash of all 3 concatenated together. E.g the expected top hash
  57   // should be 4 in the following diagram:
  58   //   4
  59   // 1 2 3
  60   std::string expected =
  61       crypto::SHA256HashString(nodes[0] + nodes[1] + nodes[2]);
  62   EXPECT_EQ(expected, ComputeTreeHashRoot(nodes, 4));
  63
  64   // Now try making the branch factor be 2, so that we
  65   // should get the following:
  66   //   6
  67   //  4 5
  68   // 1 2 3
  69   // where 4 is the hash of 1 and 2, 5 is the hash of 3, and 6 is the
  70   // hash of 4 and 5.
  71   std::string hash_of_first_2 = crypto::SHA256HashString(nodes[0] + nodes[1]);
  72   std::string hash_of_third = crypto::SHA256HashString(nodes[2]);
  73   expected = crypto::SHA256HashString(hash_of_first_2 + hash_of_third);
  74   EXPECT_EQ(expected, ComputeTreeHashRoot(nodes, 2));
  75 }
  76
  77 }  // namespace extensions