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

[Mitch Curtis]

> -----Original Message-----
> From: Edward Welbourne
> Sent: Wednesday, 3 April 2019 12:07 PM
> To: Joerg Bornemann <Joerg.Bornemann at qt.io>; Mitch Curtis
> <mitch.curtis at qt.io>
> Cc: development at qt-project.org
> Subject: Re: [Development] Supporting helper functions in auto tests by
> providing throwing Qt Test macros
> 
> On 4/2/19 5:14 PM, Mitch Curtis wrote:
> >> As described in https://bugreports.qt.io/browse/QTBUG-66320,
> >> currently Qt users are on their own if they want to call helper
> >> functions that can fail a test. The reason is documented:
> >>
> >>      Note: This macro can only be used in a test function that is
> >>      invoked by the test framework.
> 
> This note is not strictly true.  You can use it in any function that returns void.
> However, the *caller* won't return in response to it, which means it doesn't
> work *fully* in a helper.

It's true enough that we would never recommend users to use it in a helper function, hence the note.

Tests should be able to assume that any code that comes after a call to a helper means that the helper succeeded. That assumption fails if you were to use e.g. QVERIFY in that helper and it failed. I actually wrote that in my initial email, but I removed it before sending it because I didn't think anyone would be pedantic enough to warrant it.