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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/variations/caching_permuted_entropy_provider.h"
#include <string>
#include "base/basictypes.h"
#include "base/prefs/testing_pref_service.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace metrics {
// Size of the low entropy source to use for the permuted entropy provider
// in tests.
const size_t kMaxLowEntropySize = 8000;
// Field trial names used in unit tests.
const char* const kTestTrialNames[] = {"TestTrial", "AnotherTestTrial",
"NewTabButton"};
TEST(CachingPermutedEntropyProviderTest, HasConsistentResults) {
TestingPrefServiceSimple prefs;
CachingPermutedEntropyProvider::RegisterPrefs(prefs.registry());
const int kEntropyValue = 1234;
// Check that the caching provider returns the same results as the non caching
// one. Loop over the trial names twice, to test that caching returns the
// expected results.
PermutedEntropyProvider provider(kEntropyValue, kMaxLowEntropySize);
for (size_t i = 0; i < 2 * arraysize(kTestTrialNames); ++i) {
CachingPermutedEntropyProvider cached_provider(
&prefs, kEntropyValue, kMaxLowEntropySize);
const std::string trial_name =
kTestTrialNames[i % arraysize(kTestTrialNames)];
EXPECT_DOUBLE_EQ(provider.GetEntropyForTrial(trial_name, 0),
cached_provider.GetEntropyForTrial(trial_name, 0));
}
// Now, do the same test re-using the same caching provider.
CachingPermutedEntropyProvider cached_provider(
&prefs, kEntropyValue, kMaxLowEntropySize);
for (size_t i = 0; i < 2 * arraysize(kTestTrialNames); ++i) {
const std::string trial_name =
kTestTrialNames[i % arraysize(kTestTrialNames)];
EXPECT_DOUBLE_EQ(provider.GetEntropyForTrial(trial_name, 0),
cached_provider.GetEntropyForTrial(trial_name, 0));
}
}
} // namespace metrics
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