Re: [Qemu-devel] [QEMU RFC PATCH 6/7] i386: topology & APIC ID utility functions

[Eduardo Habkost]

On Mon, Jul 23, 2012 at 07:44:44PM +0000, Blue Swirl wrote:
> On Mon, Jul 23, 2012 at 7:28 PM, Eduardo Habkost <address@hidden> wrote:
> > On Mon, Jul 23, 2012 at 07:11:11PM +0000, Blue Swirl wrote:
> >> On Mon, Jul 23, 2012 at 6:59 PM, Eduardo Habkost <address@hidden> wrote:
> >> > On Mon, Jul 23, 2012 at 04:49:07PM +0000, Blue Swirl wrote:
> >> >> On Mon, Jul 16, 2012 at 5:42 PM, Eduardo Habkost <address@hidden> wrote:
> >> >> > On Sat, Jul 14, 2012 at 09:14:30AM +0000, Blue Swirl wrote:
> >> >> > [...]
> >> >> >> >> > diff --git a/tests/Makefile b/tests/Makefile
> >> >> >> >> > index b605e14..89bd890 100644
> >> >> >> >> > --- a/tests/Makefile
> >> >> >> >> > +++ b/tests/Makefile
> >> >> >> >> > @@ -15,6 +15,7 @@ check-unit-y += 
> >> >> >> >> > tests/test-string-output-visitor$(EXESUF)
> >> >> >> >> >  check-unit-y += tests/test-coroutine$(EXESUF)
> >> >> >> >> >  check-unit-y += tests/test-visitor-serialization$(EXESUF)
> >> >> >> >> >  check-unit-y += tests/test-iov$(EXESUF)
> >> >> >> >> > +check-unit-y += tests/test-x86-cpuid$(EXESUF)
> >> >> >> >>
> >> >> >> >> This probably tries to build the cpuid test also for non-x86 
> >> >> >> >> targets
> >> >> >> >> and break them all.
> >> >> >> >
> >> >> >> > I don't think there's any concept of "targets" for the check-unit 
> >> >> >> > tests.
> >> >> >>
> >> >> >> How about:
> >> >> >> check-qtest-i386-y = tests/test-x86-cpuid$(EXESUF)
> >> >> >
> >> >> > test-x86-cpuid is not a qtest test case.
> >> >>
> >> >> Why not? I don't think it is a unit test either, judging from what the
> >> >> other unit tests do.
> >> >
> >> > It is absolutely a unit test. I don't know why you don't think so. It
> >> > simply checks the results of the APIC ID calculation functions.
> >>
> >> Yes, but the other 'unit tests' (the names used here are very
> >> confusing, btw) check supporting functions like coroutines, not
> >> hardware. Hardware tests (qtest) need to bind to an architecture, in
> >> this case x86.
> >
> > test-x86-cpuid doesn't check hardware, either. It just checks the simple
> > functions that calculate APIC IDs (to make sure the math is correct).
> > Those functions aren't even used by any hardware emulation code until
> > later in the patch series (when the CPU initialization code gets changed
> > to use the new function).
> 
> By that time the function is clearly x86 HW and the check is an x86
> hardware check. QEMU as whole consists of simple functions that
> calculate something.

It's useful onily for a specific architecture, yes, but it surely
doesn't make libqtest necessary.

That's the difference between the unit tests and qtest test cases: unit
tests simply test small parts of the code (that may or may not be
hardware-specific), and qtest tests hardware emulation after starting up
a whole qemu process. It's a different kind of testing, with different
sets of goals.

I suppose you are not arguing that no function inside target-* would be
ever allowed to have a unit test written for it. That would be a very
silly constraint for people writing tests.

-- 
Eduardo