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/*
* This file is open source software, licensed to you under the terms
* of the Apache License, Version 2.0 (the "License"). See the NOTICE file
* distributed with this work for additional information regarding copyright
* ownership. 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.
*/
/*
* Copyright (C) 2017 ScyllaDB
*/
#include <seastar/testing/test_case.hh>
#include <seastar/core/do_with.hh>
#include <seastar/core/lowres_clock.hh>
#include <seastar/core/sleep.hh>
#include <ctime>
#include <algorithm>
#include <array>
#include <chrono>
using namespace seastar;
//
// Sanity check the accuracy of the steady low-resolution clock.
//
SEASTAR_TEST_CASE(steady_clock_sanity) {
return do_with(lowres_clock::now(), [](auto &&t1) {
static constexpr auto sleep_duration = std::chrono::milliseconds(100);
return ::seastar::sleep(sleep_duration).then([&t1] {
auto const elapsed = lowres_clock::now() - t1;
auto const minimum_elapsed = 0.9 * sleep_duration;
BOOST_REQUIRE(elapsed >= minimum_elapsed);
return make_ready_future<>();
});
});
}
//
// At the very least, we can verify that the low-resolution system clock is within a second of the
// high-resolution system clock.
//
SEASTAR_TEST_CASE(system_clock_sanity) {
static const auto check_matching = [] {
auto const system_time = std::chrono::system_clock::now();
auto const lowres_time = lowres_system_clock::now();
auto const t1 = std::chrono::system_clock::to_time_t(system_time);
auto const t2 = lowres_system_clock::to_time_t(lowres_time);
std::tm *lt1 = std::localtime(&t1);
std::tm *lt2 = std::localtime(&t2);
return (lt1->tm_isdst == lt2->tm_isdst) &&
(lt1->tm_year == lt2->tm_year) &&
(lt1->tm_mon == lt2->tm_mon) &&
(lt1->tm_yday == lt2->tm_yday) &&
(lt1->tm_mday == lt2->tm_mday) &&
(lt1->tm_wday == lt2->tm_wday) &&
(lt1->tm_hour == lt2->tm_hour) &&
(lt1->tm_min == lt2->tm_min) &&
(lt1->tm_sec == lt2->tm_sec);
};
//
// Check two out of three samples in order to account for the possibility that the high-resolution clock backing
// the low-resoltuion clock was captured in the range of the 990th to 999th millisecond of the second. This would
// make the low-resolution clock and the high-resolution clock disagree on the current second.
//
return do_with(0ul, 0ul, [](std::size_t& index, std::size_t& success_count) {
return repeat([&index, &success_count] {
if (index >= 3) {
BOOST_REQUIRE_GE(success_count, 2u);
return make_ready_future<stop_iteration>(stop_iteration::yes);
}
return ::seastar::sleep(std::chrono::milliseconds(10)).then([&index, &success_count] {
if (check_matching()) {
++success_count;
}
++index;
return stop_iteration::no;
});
});
});
}
//
// Verify that the low-resolution clock updates its reported time point over time.
//
SEASTAR_TEST_CASE(system_clock_dynamic) {
return do_with(lowres_system_clock::now(), [](auto &&t1) {
return seastar::sleep(std::chrono::milliseconds(100)).then([&t1] {
auto const t2 = lowres_system_clock::now();
BOOST_REQUIRE_NE(t1.time_since_epoch().count(), t2.time_since_epoch().count());
return make_ready_future<>();
});
});
}
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