Partially revert "Inline QTest::qSleep()"

This change partially reverts change
a0e0b51001.

Replacing the QTest specific sleep function with QThread::msleep()
was not a good idea. The reason is that QThread::msleep() will force
the thread to sleep to x mseconds, even if a signal woke the thread
in the meantime.

This would cause qWaitFor() to not call processEvents(), in some cases,
leading to flakyness and test failures in tests that rely on timing,
such as the animation tests in Qt Qml.

Change-Id: I0ad132cdf32be5813b2e73552d772251fe1d7f89
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

src/corelib/kernel/qtestsupport_core.cpp

@@ -45,6 +45,35 @@
 
 QT_BEGIN_NAMESPACE
 
+/*!
+    Sleeps for \a ms milliseconds, blocking execution of the
+    test. qSleep() will not do any event processing and leave your test
+    unresponsive. Network communication might time out while
+    sleeping. Use \l {QTest::qWait()} to do non-blocking sleeping.
+
+    \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.
+
+    Example:
+    \snippet code/src_qtestlib_qtestcase.cpp 23
+
+    \sa {QTest::qWait()}
+*/
+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
+}
+
 /*! \fn template <typename Functor> bool QTest::qWaitFor(Functor predicate, int timeout)
 
     Waits for \a timeout milliseconds or until the \a predicate returns true.

src/corelib/kernel/qtestsupport_core.h

@@ -48,6 +48,8 @@ QT_BEGIN_NAMESPACE
 
 namespace QTest {
 
+Q_CORE_EXPORT void qSleep(int ms);
+
 template <typename Functor>
 Q_REQUIRED_RESULT static bool qWaitFor(Functor predicate, int timeout = 5000)
 {
@@ -75,7 +77,7 @@ Q_REQUIRED_RESULT static bool qWaitFor(Functor predicate, int timeout = 5000)
 
         remaining = int(deadline.remainingTime());
         if (remaining > 0)
-            QThread::msleep(qMin(10, remaining));
+            qSleep(qMin(10, remaining));
 
         if (predicate())
             return true;

src/testlib/qtestcase.cpp

@@ -2474,24 +2474,6 @@ bool QTest::currentTestFailed()
     return QTestResult::currentTestFailed();
 }
 
-/*!
-    Sleeps for \a ms milliseconds, blocking execution of the
-    test. qSleep() will not do any event processing and leave your test
-    unresponsive. Network communication might time out while
-    sleeping. Use \l {QTest::qWait()} to do non-blocking sleeping.
-
-    \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.
-
-    Example:
-    \snippet code/src_qtestlib_qtestcase.cpp 23
-
-    \sa {QTest::qWait()}
-*/
-
 /*! \internal
  */
 QObject *QTest::testObject()

src/testlib/qtestcase.h

@@ -336,7 +336,6 @@ namespace QTest
                                          char *val1, char *val2,
                                          const char *actual, const char *expected,
                                          const char *file, int line);
-    inline void qSleep(int ms) { QThread::msleep(ms); }
     Q_TESTLIB_EXPORT void addColumnInternal(int id, const char *name);
 
     template <typename T>