QTest: port qSleep() to std::this_thread::sleep_for

As requested in code review. Big improvement, code-wise.

tst_Sleep::wait() was failing on the CI, so be more accurate by using
QElapsedTimer::durationElapsed(), which returns nanoseconds.

Pick-to: 6.6
Change-Id: I5bed6d6bd768adfdecab2475e6cbe245c20aabd7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/kernel/qtestsupport_core.cpp

@@ -3,9 +3,7 @@
 
 #include "qtestsupport_core.h"
 
-#ifdef Q_OS_WIN
-#include <qt_windows.h>
-#endif
+#include <thread>
 
 QT_BEGIN_NAMESPACE
 
@@ -17,9 +15,11 @@ QT_BEGIN_NAMESPACE
 
     \a ms must be greater than 0.
 
-    \b {Note:} The qSleep() function calls either \c nanosleep() on
-    unix or \c Sleep() on windows, so the accuracy of time spent in
-    qSleep() depends on the operating system.
+    \note Starting from Qt 6.7, this function is implemented using
+    \c {std::this_thread::sleep_for}, so the accuracy of time spent depends
+    on the Standard Library implementation. Before Qt 6.7 this function called
+    either \c nanosleep() on Unix or \c Sleep() on Windows, so the accuracy of
+    time spent in this function depended on the operating system.
 
     Example:
     \snippet code/src_qtestlib_qtestcase.cpp 23
@@ -29,13 +29,7 @@ QT_BEGIN_NAMESPACE
 Q_CORE_EXPORT void QTest::qSleep(int ms)
 {
     Q_ASSERT(ms > 0);
-
-#if defined(Q_OS_WIN)
-    Sleep(uint(ms));
-#else
-    struct timespec ts = { time_t(ms / 1000), (ms % 1000) * 1000 * 1000 };
-    nanosleep(&ts, nullptr);
-#endif
+    std::this_thread::sleep_for(std::chrono::milliseconds{ms});
 }
 
 /*! \fn template <typename Functor> bool QTest::qWaitFor(Functor predicate, int timeout)

tests/auto/testlib/selftests/sleep/CMakeLists.txt

@@ -12,6 +12,7 @@ qt_internal_add_executable(sleep
         tst_sleep.cpp
     LIBRARIES
         Qt::Test
+        Qt::CorePrivate
 )
 
 ## Scopes:

tests/auto/testlib/selftests/sleep/tst_sleep.cpp

@@ -6,6 +6,15 @@
 #include <QtCore/QElapsedTimer>
 #include <QTest>
 
+#ifdef Q_OS_UNIX
+#include <QtCore/private/qcore_unix_p.h>
+#include <QtCore/qsystemdetection.h>
+
+#include <time.h>
+#endif
+
+using namespace std::chrono_literals;
+
 class tst_Sleep: public QObject
 {
     Q_OBJECT
@@ -21,13 +30,13 @@ void tst_Sleep::sleep()
     t.start();
 
     QTest::qSleep(100);
-    QVERIFY(t.elapsed() > 90);
+    QCOMPARE_GE(t.durationElapsed(), 90ms);
 
     QTest::qSleep(1000);
-    QVERIFY(t.elapsed() > 1000);
+    QCOMPARE_GE(t.durationElapsed(), 1s);
 
     QTest::qSleep(1000 * 10); // 10 seconds
-    QVERIFY(t.elapsed() > 1000 * 10);
+    QCOMPARE_GE(t.durationElapsed(), 10s);
 }
 
 void tst_Sleep::wait()
@@ -35,17 +44,18 @@ void tst_Sleep::wait()
     QElapsedTimer t;
     t.start();
 
+    t.start();
     QTest::qWait(1);
-    QVERIFY(t.elapsed() >= 1);
+    QCOMPARE_GE(t.durationElapsed(), 1ms);
 
     QTest::qWait(10);
-    QVERIFY(t.elapsed() >= 11);
+    QCOMPARE_GE(t.durationElapsed(), 11ms);
 
     QTest::qWait(100);
-    QVERIFY(t.elapsed() >= 111);
+    QCOMPARE_GE(t.durationElapsed(), 111ms);
 
     QTest::qWait(1000);
-    QVERIFY(t.elapsed() >= 1111);
+    QCOMPARE_GE(t.durationElapsed(), 1111ms);
 }
 
 QTEST_MAIN(tst_Sleep)