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// Copyright 2020 The Pigweed Authors
//
// 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
//
// https://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 <chrono>
#include "gtest/gtest.h"
#include "pw_chrono/system_clock.h"
#include "pw_preprocessor/util.h"
using namespace std::chrono_literals;
namespace pw::chrono {
namespace {
extern "C" {
// Functions defined in system_clock_facade_test_c.c which call the API from C.
pw_chrono_SystemClock_TimePoint pw_chrono_SystemClock_CallNow();
pw_chrono_SystemClock_Duration pw_chrono_SystemClock_CallTimeElapsed(
pw_chrono_SystemClock_TimePoint last_time,
pw_chrono_SystemClock_TimePoint current_time);
pw_chrono_SystemClock_Nanoseconds pw_chrono_SystemClock_CallDurationToNsFloor(
pw_chrono_SystemClock_Duration ticks);
} // extern "C"
// While testing that the clock ticks (i.e. moves forward) we want to ensure a
// failure can be reported instead of deadlocking the test until it passes.
// Given that there isn't really a good heuristic for this we instead make some
// wild assumptions to bound the maximum busy loop iterations.
// - Assume our clock is < 6Ghz
// - Assume we can check the clock in a single cycle
// - Wait for up to 1/10th of a second @ 6Ghz, this may be a long period on a
// slower (i.e. real) machine.
constexpr uint64_t kMaxIterations = 6'000'000'000 / 10;
TEST(SystemClock, Now) {
const SystemClock::time_point start_time = SystemClock::now();
// Verify the clock moves forward.
bool clock_moved_forward = false;
for (uint64_t i = 0; i < kMaxIterations; ++i) {
if (SystemClock::now() > start_time) {
clock_moved_forward = true;
break;
}
}
EXPECT_TRUE(clock_moved_forward);
}
TEST(VirtualSystemClock, Now) {
auto& clock = VirtualSystemClock::RealClock();
const SystemClock::time_point start_time = clock.now();
// Verify the clock moves forward.
bool clock_moved_forward = false;
for (uint64_t i = 0; i < kMaxIterations; ++i) {
if (clock.now() > start_time) {
clock_moved_forward = true;
break;
}
}
EXPECT_TRUE(clock_moved_forward);
}
TEST(SystemClock, NowInC) {
const pw_chrono_SystemClock_TimePoint start_time =
pw_chrono_SystemClock_CallNow();
// Verify the clock moves forward.
bool clock_moved_forward = false;
for (uint64_t i = 0; i < kMaxIterations; ++i) {
if (pw_chrono_SystemClock_CallNow().duration_since_epoch.ticks >
start_time.duration_since_epoch.ticks) {
clock_moved_forward = true;
break;
}
}
EXPECT_TRUE(clock_moved_forward);
}
TEST(SystemClock, TimeElapsedInC) {
const pw_chrono_SystemClock_TimePoint first = pw_chrono_SystemClock_CallNow();
const pw_chrono_SystemClock_TimePoint last = pw_chrono_SystemClock_CallNow();
static_assert(SystemClock::is_monotonic);
EXPECT_GE(0, pw_chrono_SystemClock_CallTimeElapsed(last, first).ticks);
}
TEST(SystemClock, DurationCastInC) {
// We can't control the SystemClock's period configuration, so just in case
// 42 hours cannot be accurately expressed in integer ticks, round the
// duration w/ floor.
static constexpr auto kRoundedArbitraryDuration =
std::chrono::floor<SystemClock::duration>(42h);
static constexpr pw_chrono_SystemClock_Duration kRoundedArbitraryDurationInC =
PW_SYSTEM_CLOCK_H_FLOOR(42);
EXPECT_EQ(
std::chrono::floor<std::chrono::nanoseconds>(kRoundedArbitraryDuration)
.count(),
pw_chrono_SystemClock_CallDurationToNsFloor(
kRoundedArbitraryDurationInC));
}
} // namespace
} // namespace pw::chrono
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