/*
 * Copyright © Canonical Ltd.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 or 3 as
 * published by the Free Software Foundation.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "mir/anonymous_shm_file.h"
#include <gtest/gtest.h>

TEST(AnonymousShmFile, is_created)
{
    size_t const file_size{100};

    mir::AnonymousShmFile shm_file{file_size};

    EXPECT_GE(shm_file.fd(), 0);
}

TEST(AnonymousShmFile, has_correct_size)
{
    size_t const file_size{100};

    mir::AnonymousShmFile shm_file{file_size};

    struct stat stat;
    fstat(shm_file.fd(), &stat);

    EXPECT_EQ(static_cast<off_t>(file_size), stat.st_size);
}

TEST(AnonymousShmFile, writing_to_base_ptr_writes_to_file)
{
    size_t const file_size{100};

    mir::AnonymousShmFile shm_file{file_size};

    auto base_ptr = reinterpret_cast<uint8_t*>(shm_file.base_ptr());

    for (size_t i = 0; i < file_size; i++)
    {
        base_ptr[i] = i;
    }

    std::vector<unsigned char> buffer(file_size);

    EXPECT_EQ(static_cast<ssize_t>(file_size),
              read(shm_file.fd(), buffer.data(), file_size));

    for (size_t i = 0; i < file_size; i++)
    {
        EXPECT_EQ(base_ptr[i], buffer[i]) << "i=" << i;
    }
}
