SurfaceFlinger: Mock Clock for OneShotTimerTest
Use a mock clock for OneShotTimerTest instead of a real time clock
to remove flakiness in the test.
Bug: 185150860
Test: adb shell /data/nativetest64/libsurfaceflinger_unittest/libsurfaceflinger_unittest
Change-Id: Iaea32548319eae29c6dee62efbf4ba2efc827267
diff --git a/services/surfaceflinger/Scheduler/OneShotTimer.cpp b/services/surfaceflinger/Scheduler/OneShotTimer.cpp
index ce3b0c6..d659398 100644
--- a/services/surfaceflinger/Scheduler/OneShotTimer.cpp
+++ b/services/surfaceflinger/Scheduler/OneShotTimer.cpp
@@ -40,13 +40,21 @@
namespace android {
namespace scheduler {
+std::chrono::steady_clock::time_point OneShotTimer::Clock::now() const {
+ return std::chrono::steady_clock::now();
+}
+
OneShotTimer::OneShotTimer(std::string name, const Interval& interval,
const ResetCallback& resetCallback,
- const TimeoutCallback& timeoutCallback)
- : mName(std::move(name)),
+ const TimeoutCallback& timeoutCallback,
+ std::unique_ptr<OneShotTimer::Clock> clock)
+ : mClock(std::move(clock)),
+ mName(std::move(name)),
mInterval(interval),
mResetCallback(resetCallback),
- mTimeoutCallback(timeoutCallback) {}
+ mTimeoutCallback(timeoutCallback) {
+ LOG_ALWAYS_FATAL_IF(!mClock, "Clock must not be provided");
+}
OneShotTimer::~OneShotTimer() {
stop();
@@ -112,7 +120,7 @@
break;
}
- auto triggerTime = std::chrono::steady_clock::now() + mInterval;
+ auto triggerTime = mClock->now() + mInterval;
state = TimerState::WAITING;
while (state == TimerState::WAITING) {
constexpr auto zero = std::chrono::steady_clock::duration::zero();
@@ -128,10 +136,9 @@
state = checkForResetAndStop(state);
if (state == TimerState::RESET) {
- triggerTime = std::chrono::steady_clock::now() + mInterval;
+ triggerTime = mClock->now() + mInterval;
state = TimerState::WAITING;
- } else if (state == TimerState::WAITING &&
- (triggerTime - std::chrono::steady_clock::now()) <= zero) {
+ } else if (state == TimerState::WAITING && (triggerTime - mClock->now()) <= zero) {
triggerTimeout = true;
state = TimerState::IDLE;
}
diff --git a/services/surfaceflinger/Scheduler/OneShotTimer.h b/services/surfaceflinger/Scheduler/OneShotTimer.h
index 3690ce7..7285427 100644
--- a/services/surfaceflinger/Scheduler/OneShotTimer.h
+++ b/services/surfaceflinger/Scheduler/OneShotTimer.h
@@ -36,8 +36,17 @@
using ResetCallback = std::function<void()>;
using TimeoutCallback = std::function<void()>;
+ class Clock {
+ public:
+ Clock() = default;
+ virtual ~Clock() = default;
+
+ virtual std::chrono::steady_clock::time_point now() const;
+ };
+
OneShotTimer(std::string name, const Interval& interval, const ResetCallback& resetCallback,
- const TimeoutCallback& timeoutCallback);
+ const TimeoutCallback& timeoutCallback,
+ std::unique_ptr<OneShotTimer::Clock> = std::make_unique<OneShotTimer::Clock>());
~OneShotTimer();
// Initializes and turns on the idle timer.
@@ -78,6 +87,9 @@
// Thread waiting for timer to expire.
std::thread mThread;
+ // Clock object for the timer. Mocked in unit tests.
+ std::unique_ptr<Clock> mClock;
+
// Semaphore to keep mThread synchronized.
sem_t mSemaphore;
diff --git a/services/surfaceflinger/tests/unittests/OneShotTimerTest.cpp b/services/surfaceflinger/tests/unittests/OneShotTimerTest.cpp
index cfbb3f5..a1f0588 100644
--- a/services/surfaceflinger/tests/unittests/OneShotTimerTest.cpp
+++ b/services/surfaceflinger/tests/unittests/OneShotTimerTest.cpp
@@ -19,6 +19,7 @@
#include <gmock/gmock.h>
#include <gtest/gtest.h>
#include <utils/Log.h>
+#include <utils/Timers.h>
#include "AsyncCallRecorder.h"
#include "Scheduler/OneShotTimer.h"
@@ -28,21 +29,22 @@
namespace android {
namespace scheduler {
+class FakeClock : public OneShotTimer::Clock {
+public:
+ virtual ~FakeClock() = default;
+ std::chrono::steady_clock::time_point now() const override { return mNow; }
+
+ void advanceTime(std::chrono::nanoseconds delta) { mNow += delta; }
+
+private:
+ std::chrono::steady_clock::time_point mNow;
+};
+
class OneShotTimerTest : public testing::Test {
protected:
OneShotTimerTest() = default;
~OneShotTimerTest() override = default;
- // This timeout should be used when a 3ms callback is expected.
- // While the tests typically request a callback after 3ms, the scheduler
- // does not always cooperate, at it can take significantly longer (observed
- // 30ms).
- static constexpr auto waitTimeForExpected3msCallback = 100ms;
-
- // This timeout should be used when an 3ms callback is not expected.
- // Note that there can be false-negatives if the callback happens later.
- static constexpr auto waitTimeForUnexpected3msCallback = 6ms;
-
AsyncCallRecorder<void (*)()> mResetTimerCallback;
AsyncCallRecorder<void (*)()> mExpiredTimerCallback;
@@ -56,162 +58,179 @@
namespace {
TEST_F(OneShotTimerTest, createAndDestroyTest) {
+ FakeClock* clock = new FakeClock();
mIdleTimer = std::make_unique<scheduler::OneShotTimer>(
- "TestTimer", 3ms, [] {}, [] {});
+ "TestTimer", 3ms, [] {}, [] {}, std::unique_ptr<FakeClock>(clock));
}
TEST_F(OneShotTimerTest, startStopTest) {
- mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 30ms,
+ FakeClock* clock = new FakeClock();
+ mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 1ms,
mResetTimerCallback.getInvocable(),
- mExpiredTimerCallback.getInvocable());
- auto startTime = std::chrono::steady_clock::now();
+ mExpiredTimerCallback.getInvocable(),
+ std::unique_ptr<FakeClock>(clock));
mIdleTimer->start();
EXPECT_TRUE(mResetTimerCallback.waitForCall().has_value());
- // The idle timer fires after 30ms, so there should be no callback within
- // 25ms (waiting for a callback for the full 30ms would be problematic).
- bool callbackCalled = mExpiredTimerCallback.waitForCall(25ms).has_value();
- // Under ideal conditions there should be no event. But occasionally
- // it is possible that the wait just prior takes more than 30ms, and
- // a callback is observed. We check the elapsed time since before the OneShotTimer
- // thread was started as a sanity check to not have a flakey test.
- EXPECT_FALSE(callbackCalled && std::chrono::steady_clock::now() - startTime < 30ms);
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
- std::this_thread::sleep_for(std::chrono::milliseconds(25));
- EXPECT_FALSE(mResetTimerCallback.waitForCall().has_value());
+ clock->advanceTime(2ms);
+ EXPECT_TRUE(mExpiredTimerCallback.waitForCall().has_value());
+
+ clock->advanceTime(2ms);
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
mIdleTimer->stop();
}
TEST_F(OneShotTimerTest, resetTest) {
- mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 20ms,
+ FakeClock* clock = new FakeClock();
+ mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 1ms,
mResetTimerCallback.getInvocable(),
- mExpiredTimerCallback.getInvocable());
+ mExpiredTimerCallback.getInvocable(),
+ std::unique_ptr<FakeClock>(clock));
+
mIdleTimer->start();
EXPECT_TRUE(mResetTimerCallback.waitForCall().has_value());
- // Observe any event that happens in about 25ms. We don't care if one was
- // observed or not.
- mExpiredTimerCallback.waitForCall(25ms).has_value();
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ clock->advanceTime(2ms);
+ EXPECT_TRUE(mExpiredTimerCallback.waitForCall().has_value());
mIdleTimer->reset();
EXPECT_TRUE(mResetTimerCallback.waitForCall().has_value());
- // There may have been a race with the reset. Clear any callbacks we
- // received right afterwards.
- clearPendingCallbacks();
- // A single callback should be generated after 30ms
- EXPECT_TRUE(
- mExpiredTimerCallback.waitForCall(waitTimeForExpected3msCallback + 30ms).has_value());
- // After one event, it should be idle, and not generate another.
- EXPECT_FALSE(
- mExpiredTimerCallback.waitForCall(waitTimeForUnexpected3msCallback * 10).has_value());
- mIdleTimer->stop();
- // Final quick check that no more callback were observed.
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(0ms).has_value());
- EXPECT_FALSE(mResetTimerCallback.waitForCall(0ms).has_value());
+ clock->advanceTime(2ms);
+ EXPECT_TRUE(mExpiredTimerCallback.waitForCall().has_value());
+
+ clock->advanceTime(2ms);
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
}
TEST_F(OneShotTimerTest, resetBackToBackTest) {
- mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 20ms,
+ FakeClock* clock = new FakeClock();
+ mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 1ms,
mResetTimerCallback.getInvocable(),
- mExpiredTimerCallback.getInvocable());
+ mExpiredTimerCallback.getInvocable(),
+ std::unique_ptr<FakeClock>(clock));
mIdleTimer->start();
EXPECT_TRUE(mResetTimerCallback.waitForCall().has_value());
mIdleTimer->reset();
- EXPECT_FALSE(mResetTimerCallback.waitForCall(1ms).has_value());
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(waitTimeForUnexpected3msCallback).has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
mIdleTimer->reset();
- EXPECT_FALSE(mResetTimerCallback.waitForCall(1ms).has_value());
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(waitTimeForUnexpected3msCallback).has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
mIdleTimer->reset();
- EXPECT_FALSE(mResetTimerCallback.waitForCall(1ms).has_value());
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(waitTimeForUnexpected3msCallback).has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
mIdleTimer->reset();
- EXPECT_FALSE(mResetTimerCallback.waitForCall(1ms).has_value());
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(waitTimeForUnexpected3msCallback).has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
- // A single callback should be generated after 30ms
- EXPECT_TRUE(
- mExpiredTimerCallback.waitForCall(waitTimeForExpected3msCallback + 30ms).has_value());
+ clock->advanceTime(2ms);
+ EXPECT_TRUE(mExpiredTimerCallback.waitForCall().has_value());
+
mIdleTimer->stop();
+ clock->advanceTime(2ms);
// Final quick check that no more callback were observed.
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(0ms).has_value());
- EXPECT_FALSE(mResetTimerCallback.waitForCall(0ms).has_value());
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
}
TEST_F(OneShotTimerTest, startNotCalledTest) {
- mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 3ms,
+ FakeClock* clock = new FakeClock();
+ mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 1ms,
mResetTimerCallback.getInvocable(),
- mExpiredTimerCallback.getInvocable());
+ mExpiredTimerCallback.getInvocable(),
+ std::unique_ptr<FakeClock>(clock));
// The start hasn't happened, so the callback does not happen.
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(waitTimeForUnexpected3msCallback).has_value());
- EXPECT_FALSE(mResetTimerCallback.waitForCall().has_value());
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
mIdleTimer->stop();
+ clock->advanceTime(2ms);
// Final quick check that no more callback were observed.
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(0ms).has_value());
- EXPECT_FALSE(mResetTimerCallback.waitForCall(0ms).has_value());
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
}
TEST_F(OneShotTimerTest, idleTimerIdlesTest) {
- mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 3ms,
+ FakeClock* clock = new FakeClock();
+ mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 1ms,
mResetTimerCallback.getInvocable(),
- mExpiredTimerCallback.getInvocable());
+ mExpiredTimerCallback.getInvocable(),
+ std::unique_ptr<FakeClock>(clock));
mIdleTimer->start();
EXPECT_TRUE(mResetTimerCallback.waitForCall().has_value());
+ clock->advanceTime(2ms);
+ EXPECT_TRUE(mExpiredTimerCallback.waitForCall().has_value());
- // A callback should be generated after 3ms
- EXPECT_TRUE(mExpiredTimerCallback.waitForCall(waitTimeForExpected3msCallback).has_value());
- // After one event, it should be idle, and not generate another.
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(waitTimeForUnexpected3msCallback).has_value());
- // Once reset, it should generate another
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
+
mIdleTimer->reset();
EXPECT_TRUE(mResetTimerCallback.waitForCall().has_value());
- EXPECT_TRUE(mExpiredTimerCallback.waitForCall(waitTimeForExpected3msCallback).has_value());
+ clock->advanceTime(2ms);
+ EXPECT_TRUE(mExpiredTimerCallback.waitForCall().has_value());
mIdleTimer->stop();
+ clock->advanceTime(2ms);
// Final quick check that no more callback were observed.
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(0ms).has_value());
- EXPECT_FALSE(mResetTimerCallback.waitForCall(0ms).has_value());
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
}
TEST_F(OneShotTimerTest, timeoutCallbackExecutionTest) {
- mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 3ms,
+ FakeClock* clock = new FakeClock();
+ mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 1ms,
mResetTimerCallback.getInvocable(),
- mExpiredTimerCallback.getInvocable());
+ mExpiredTimerCallback.getInvocable(),
+ std::unique_ptr<FakeClock>(clock));
mIdleTimer->start();
EXPECT_TRUE(mResetTimerCallback.waitForCall().has_value());
- EXPECT_TRUE(mExpiredTimerCallback.waitForCall(waitTimeForExpected3msCallback).has_value());
+
+ clock->advanceTime(2ms);
+ EXPECT_TRUE(mExpiredTimerCallback.waitForCall().has_value());
mIdleTimer->stop();
+ clock->advanceTime(2ms);
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
}
TEST_F(OneShotTimerTest, noCallbacksAfterStopAndResetTest) {
- mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 3ms,
+ FakeClock* clock = new FakeClock();
+ mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 1ms,
mResetTimerCallback.getInvocable(),
- mExpiredTimerCallback.getInvocable());
+ mExpiredTimerCallback.getInvocable(),
+ std::unique_ptr<FakeClock>(clock));
mIdleTimer->start();
EXPECT_TRUE(mResetTimerCallback.waitForCall().has_value());
- EXPECT_TRUE(mExpiredTimerCallback.waitForCall(waitTimeForExpected3msCallback).has_value());
+ clock->advanceTime(2ms);
+ EXPECT_TRUE(mExpiredTimerCallback.waitForCall().has_value());
mIdleTimer->stop();
- clearPendingCallbacks();
mIdleTimer->reset();
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(waitTimeForUnexpected3msCallback).has_value());
- EXPECT_FALSE(mResetTimerCallback.waitForCall().has_value());
+ clock->advanceTime(2ms);
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
}
TEST_F(OneShotTimerTest, noCallbacksAfterStopTest) {
- mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 3ms,
+ FakeClock* clock = new FakeClock();
+ mIdleTimer = std::make_unique<scheduler::OneShotTimer>("TestTimer", 1ms,
mResetTimerCallback.getInvocable(),
- mExpiredTimerCallback.getInvocable());
+ mExpiredTimerCallback.getInvocable(),
+ std::unique_ptr<FakeClock>(clock));
mIdleTimer->start();
EXPECT_TRUE(mResetTimerCallback.waitForCall().has_value());
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
mIdleTimer->stop();
- clearPendingCallbacks();
mIdleTimer->reset();
+ clock->advanceTime(2ms);
// No more idle events should be observed
- EXPECT_FALSE(mExpiredTimerCallback.waitForCall(waitTimeForUnexpected3msCallback).has_value());
- EXPECT_FALSE(mResetTimerCallback.waitForCall().has_value());
+ EXPECT_FALSE(mExpiredTimerCallback.waitForUnexpectedCall().has_value());
+ EXPECT_FALSE(mResetTimerCallback.waitForUnexpectedCall().has_value());
}
} // namespace