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https://github.com/abseil/abseil-cpp.git
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1fdbcb591f
decoupling code that uses time from the code that creates a point in time. You can use this to your advantage by injecting Clocks into interfaces rather than having implementations call absl::Now() directly. absl::Clock::GetRealClock() returns an absl::Clock backed by absl::Now(). Add absl::SimulatedClock, a test-only Clock implementation that does not "tick" on its own. Time is advanced by explicit calls to the AdvanceTime() or SetTime() functions. This is intended to be used for dependency injection in tests to test how code behaves under simulated time conditions. PiperOrigin-RevId: 862858341 Change-Id: Ied9946dd84063c95505269971d3c996d4b66c6d8
129 lines
3.7 KiB
C++
129 lines
3.7 KiB
C++
// Copyright 2026 The Abseil Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "absl/time/clock_interface.h"
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#include <cstdint>
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#include <functional>
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#include <thread> // NOLINT(build/c++11)
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#include <vector>
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#include "gmock/gmock.h"
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#include "gtest/gtest.h"
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#include "absl/functional/bind_front.h"
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#include "absl/synchronization/mutex.h"
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#include "absl/synchronization/notification.h"
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#include "absl/time/clock.h"
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#include "absl/time/time.h"
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namespace {
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constexpr absl::Duration kLongPause = absl::Milliseconds(150);
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#ifdef _MSC_VER
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// As of 2026-01-29, multithreaded tests on MSVC are too flaky.
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const char* kSkipFlakyReason =
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"Skipping this timing test because it is too flaky";
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#else
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const char* kSkipFlakyReason = nullptr;
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#endif
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void AwaitWithDeadlineAndNotify(absl::Clock* clock, absl::Mutex* mu,
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absl::Condition* cond, absl::Time wakeup_time,
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absl::Notification* note, bool* return_val) {
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mu->lock_shared();
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*return_val = clock->AwaitWithDeadline(mu, *cond, wakeup_time);
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mu->unlock_shared();
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note->Notify();
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}
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TEST(RealClockTest, AwaitWithVeryLargeDeadline) {
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if (kSkipFlakyReason != nullptr) {
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GTEST_SKIP() << kSkipFlakyReason;
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}
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absl::Clock& clock = absl::Clock::GetRealClock();
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absl::Mutex mu;
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bool f = false;
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absl::Condition cond(&f);
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absl::Notification note;
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bool return_val;
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std::thread thread(AwaitWithDeadlineAndNotify, &clock, &mu, &cond,
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absl::InfiniteFuture(), ¬e, &return_val);
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EXPECT_FALSE(note.HasBeenNotified());
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mu.lock();
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f = true;
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mu.unlock();
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absl::SleepFor(kLongPause);
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EXPECT_TRUE(note.HasBeenNotified());
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EXPECT_TRUE(return_val);
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note.WaitForNotification(); // In case the expectation fails.
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thread.join();
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}
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TEST(RealClockTest, AwaitWithPastDeadline) {
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if (kSkipFlakyReason != nullptr) {
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GTEST_SKIP() << kSkipFlakyReason;
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}
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absl::Clock& clock = absl::Clock::GetRealClock();
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absl::Mutex mu;
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bool f = false;
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absl::Condition cond(&f);
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absl::Notification note;
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bool return_val;
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std::thread thread(AwaitWithDeadlineAndNotify, &clock, &mu, &cond,
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clock.TimeNow() - absl::Seconds(10), ¬e, &return_val);
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absl::Time start = absl::Now();
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note.WaitForNotification(); // AwaitWithDeadline() should ping note.
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EXPECT_GE(kLongPause, absl::Now() - start);
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EXPECT_FALSE(return_val);
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thread.join();
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}
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TEST(RealClockTest, AwaitWithSmallDeadline) {
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if (kSkipFlakyReason != nullptr) {
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GTEST_SKIP() << kSkipFlakyReason;
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}
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absl::Clock& clock = absl::Clock::GetRealClock();
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absl::Mutex mu;
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bool f = false;
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absl::Condition cond(&f);
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for (int i = 0; i < 5; ++i) {
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absl::Duration wait_time = absl::Milliseconds(i);
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absl::Duration elapsed_time;
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{
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absl::MutexLock lock(mu);
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absl::Time start = clock.TimeNow();
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absl::Time wakeup_time = start + wait_time;
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EXPECT_FALSE(clock.AwaitWithDeadline(&mu, cond, wakeup_time));
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elapsed_time = clock.TimeNow() - start;
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}
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if (elapsed_time >= absl::ZeroDuration()) { // ignore jumps backwards
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// 60 microseconds of slop to allow for non-monotonic clocks.
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EXPECT_GE(elapsed_time, wait_time - absl::Microseconds(60));
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}
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}
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}
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} // namespace
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