1 // Copyright 2013 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 "chrome/common/metrics/caching_permuted_entropy_provider.h" 6 7 #include <string> 8 9 #include "base/basictypes.h" 10 #include "base/prefs/testing_pref_service.h" 11 #include "testing/gtest/include/gtest/gtest.h" 12 13 namespace metrics { 14 15 // Size of the low entropy source to use for the permuted entropy provider 16 // in tests. 17 const size_t kMaxLowEntropySize = 8000; 18 19 // Field trial names used in unit tests. 20 const char* const kTestTrialNames[] = { "TestTrial", "AnotherTestTrial", 21 "NewTabButton" }; 22 23 TEST(CachingPermutedEntropyProviderTest, HasConsistentResults) { 24 TestingPrefServiceSimple prefs; 25 CachingPermutedEntropyProvider::RegisterPrefs(prefs.registry()); 26 const int kEntropyValue = 1234; 27 28 // Check that the caching provider returns the same results as the non caching 29 // one. Loop over the trial names twice, to test that caching returns the 30 // expected results. 31 PermutedEntropyProvider provider(kEntropyValue, kMaxLowEntropySize); 32 for (size_t i = 0; i < 2 * arraysize(kTestTrialNames); ++i) { 33 CachingPermutedEntropyProvider cached_provider(&prefs, kEntropyValue, 34 kMaxLowEntropySize); 35 const std::string trial_name = 36 kTestTrialNames[i % arraysize(kTestTrialNames)]; 37 EXPECT_EQ(provider.GetEntropyForTrial(trial_name, 0), 38 cached_provider.GetEntropyForTrial(trial_name, 0)); 39 } 40 41 // Now, do the same test re-using the same caching provider. 42 CachingPermutedEntropyProvider cached_provider(&prefs, kEntropyValue, 43 kMaxLowEntropySize); 44 for (size_t i = 0; i < 2 * arraysize(kTestTrialNames); ++i) { 45 const std::string trial_name = 46 kTestTrialNames[i % arraysize(kTestTrialNames)]; 47 EXPECT_EQ(provider.GetEntropyForTrial(trial_name, 0), 48 cached_provider.GetEntropyForTrial(trial_name, 0)); 49 } 50 } 51 52 } // namespace metrics 53
