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80 lines
1.8 KiB
80 lines
1.8 KiB
//
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// Copyright (C) 2014 The Android Open Source Project
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#include "update_engine/update_manager/prng.h"
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#include <vector>
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#include <gtest/gtest.h>
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using std::vector;
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namespace chromeos_update_manager {
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TEST(UmPRNGTest, ShouldBeDeterministic) {
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PRNG a(42);
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PRNG b(42);
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for (int i = 0; i < 1000; ++i) {
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EXPECT_EQ(a.Rand(), b.Rand()) << "Iteration i=" << i;
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}
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}
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TEST(UmPRNGTest, SeedChangesGeneratedSequence) {
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PRNG a(42);
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PRNG b(5);
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vector<uint32_t> values_a;
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vector<uint32_t> values_b;
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for (int i = 0; i < 100; ++i) {
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values_a.push_back(a.Rand());
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values_b.push_back(b.Rand());
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}
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EXPECT_NE(values_a, values_b);
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}
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TEST(UmPRNGTest, IsNotConstant) {
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PRNG prng(5);
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uint32_t initial_value = prng.Rand();
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bool prng_is_constant = true;
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for (int i = 0; i < 100; ++i) {
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if (prng.Rand() != initial_value) {
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prng_is_constant = false;
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break;
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}
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}
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EXPECT_FALSE(prng_is_constant) << "After 100 iterations.";
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}
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TEST(UmPRNGTest, RandCoversRange) {
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PRNG a(42);
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int hits[11] = {0};
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for (int i = 0; i < 1000; i++) {
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int r = a.RandMinMax(0, 10);
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ASSERT_LE(0, r);
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ASSERT_GE(10, r);
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hits[r]++;
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}
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for (auto& hit : hits)
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EXPECT_LT(0, hit);
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}
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} // namespace chromeos_update_manager
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