[Development] Supporting helper functions in auto tests by providing throwing Qt Test macros

[Giuseppe D'Angelo]

Hi,

Il 02/04/19 17:14, Mitch Curtis ha scritto:
> Quoting the commit message here:
> 
>      WIP: Add _THROW variants to testlib macros
> 
>      This allows using Qt Test macros in helper functions, avoiding the need
>      to write a lot of boilerplate code as seen with alternative approaches.

I may like the overall approach. However, this would imply that such 
tests require exceptions / RTTI turned on inside QtTestLib / user code; 
is it "OK" in the grand scheme of things?

I have a question regarding this particular implementation, that is, why 
adding dedicated testing functions? Can't you "simply" change the 
currently existing QVERIFY/QCOMPARE to throw exceptions in case of 
failure, instead of returning from the current test function? This would 
achieve major consistency -- simply use the same functions everywhere, 
no matter what.

This idea isn't failproof, as:

1) it requires the exception to propagate through a direct 
QMetaObject::invoke (that is, whatever mechanism testlib uses to invoke 
the test functions); but that should be already supported and tested, even.

2) it causes a minor SC in case the user was doing it wrong -- "catching 
all", without rethrowing an unknown exception type. Before, a failing 
test would simply return. With this idea, it would throw, and the 
exception could be caught by the catch all and not used to block the 
execution of the current test function.

The last can be solved in a very simple way (e.g. make this mechanism 
opt-in; and also provide something to the user to test if the current 
catch-all is a Qt test failure, via std::current_exception()).


My 2 c,
-- 
Giuseppe D'Angelo | giuseppe.dangelo at kdab.com | Senior Software Engineer
KDAB (France) S.A.S., a KDAB Group company
Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com
KDAB - The Qt, C++ and OpenGL Experts

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