QObject::startTimer() returns 0 in case of failure, for example when
someone tries to register a timer with a negative interval.
However, QTimer internally uses -1 as an invalid timer id.
This could lead to a situation when the timer was not really started,
but QTimer::isActive() returned true.
This patch fixes it in two ways:
- check the return value of QObject::startTimer() and treat 0 as an
error.
- do not treat 0 as a valid timer id when calculating the active state.
As a drive-by: move the `using namespace std::chrono_literals;`
declaration to the top of tst_qtimer.cpp, so that we do not need to
repeat it in each test case.
Fixes: QTBUG-122087
Pick-to: 6.7 6.6 6.5
Change-Id: I0e21152b2173ebb5fb0dada1b99a903a321ca9c4
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>