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