android/android-emu/android/snapshot/RamSaver_unittest.cpp

// Copyright (C) 2018 The Android Open Source Project
//
// This software is licensed under the terms of the GNU General Public
// License version 2, as published by the Free Software Foundation, and
// may be copied, distributed, and modified under those terms.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

#include "android/base/AlignedBuf.h"
#include "android/base/StringView.h"
#include "android/base/misc/FileUtils.h"
#include "android/base/testing/TestTempDir.h"
#include "android/snapshot/RamSnapshotTesting.h"

#include <gtest/gtest.h>

#include <memory>
#include <random>
#include <vector>

using android::AlignedBuf;
using android::base::StringView;
using android::base::TestTempDir;

namespace android {
namespace snapshot {

class RamSaverTest : public ::testing::Test {
protected:
    void SetUp() override { mTempDir.reset(new TestTempDir("ramsavertest")); }

    void TearDown() override { mTempDir.reset(); }

    std::unique_ptr<TestTempDir> mTempDir;
};

static void checkFileEqualToBuffer(const uint8_t* buffer,
                                   size_t size,
                                   StringView filename) {
    const auto fileContents = android::readFileIntoString(filename);

    EXPECT_TRUE(fileContents);
    EXPECT_LE(size, fileContents->size());
    for (size_t i = 0; i < size; i++) {
        EXPECT_EQ((char)buffer[i], fileContents->at(i));
    }
}

// Save 10 pages that are all zero with no compression.
TEST_F(RamSaverTest, Simple) {
    std::string ramSaverTestPath = mTempDir->makeSubPath("ram.bin");

    const int numPages = 10;

    // Create aligned buf
    TestRamBuffer testRam(numPages * kTestingPageSize);
    uint8_t* ramAligned = testRam.data();
    memset(ramAligned, 0, numPages * kTestingPageSize);

    saveRamSingleBlock(RamSaver::Flags::None,
                       makeRam(
                           "ramSaverTestBlock",
                           testRam.data(),
                           (int64_t)testRam.size()),
                       ramSaverTestPath);

    const std::vector<uint8_t> golden = {
        0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x8, 0x0, 0x0, 0x0, 0x2, 0x0, 0x0,
        0x0, 0x0, 0x0, 0x0, 0x0, 0xa, 0x11, 0x72, 0x61, 0x6d, 0x53, 0x61, 0x76,
        0x65, 0x72, 0x54, 0x65, 0x73, 0x74, 0x42, 0x6c, 0x6f, 0x63, 0x6b, 0x0,
        0x0, 0x0, 0xa, 0x0, 0x0, 0x10, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
        0x0, 0x0, 0x0, 
    };

    checkFileEqualToBuffer(golden.data(), golden.size(), ramSaverTestPath);
}

// Save 1 nonzero page with compression.
TEST_F(RamSaverTest, SimpleNonzero) {
    std::string ramSaverTestPath = mTempDir->makeSubPath("ram.bin");

    const int numPages = 1;

    // Create aligned buf
    TestRamBuffer testRam(numPages * kTestingPageSize);
    uint8_t* ramAligned = testRam.data();
    memset(ramAligned, 0xff, numPages * kTestingPageSize);

    saveRamSingleBlock(RamSaver::Flags::Compress,
                       makeRam(
                           "ramSaverTestBlock",
                           testRam.data(),
                           (int64_t)testRam.size()),
                       ramSaverTestPath);

    const std::vector<uint8_t> golden = {
        0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x22, 0x1f, 0xff, 0x1, 0x0, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xf6, 0x50, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0, 0x0, 0x0,
        0x2, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x1, 0x11, 0x72, 0x61, 0x6d,
        0x53, 0x61, 0x76, 0x65, 0x72, 0x54, 0x65, 0x73, 0x74, 0x42, 0x6c, 0x6f,
        0x63, 0x6b, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x10, 0x0, 0x0, 0x0, 0x0, 0x0,
        0x0, 0x0, 0x0, 0x0, 0x1a, 0x0, 0xa7, 0x33, 0xb8, 0x81, 0x91, 0x17, 0x52,
        0xb, 0xfa, 0xeb, 0x17, 0xde, 0xd2, 0x1a, 0x16, 0xc4,
    };

    checkFileEqualToBuffer(golden.data(), golden.size(), ramSaverTestPath);
}

// Save 100 pages with compression, some zero, some nonzero.
// Does not actually check contents; just performs saving.
TEST_F(RamSaverTest, BasicRandom) {
    std::string ramSaverTestPath = mTempDir->makeSubPath("random-ram-100.bin");

    const int numPages = 100;
    const float zeroPageChance = 0.5;

    auto testRam = generateRandomRam(numPages, zeroPageChance);

    saveRamSingleBlock(RamSaver::Flags::Compress,
                       makeRam(
                           "ramSaverTestBlock",
                           testRam.data(),
                           (int64_t)testRam.size()),
                       ramSaverTestPath);
}

}  // namespace snapshot
}  // namespace android