[6.x] Fix undefined property in WithFaker

[driesvints]

#30992 introduced a side effect where resolving faker would fail if the trait was implemented on a class that hasn't set the framework as a property.

Fixes #31071

[crynobone]

Does this fully solve the problem?

If $this->app doesn't exist then config() helper usage should actually failed as well.

In 7.x we could split the basic usage of WithFaker to illuminate/testing and only resolves via $this->app for Illuminate\Foundation\Testing\WithFaker.

[driesvints]

@crynobone no, the framework can still be initialized so the config helper can still work. The problem was that if the trait was used on a class that doesn't has an "app" property that it would give a notice about the non-existing property.

[telkins]

FYI...it's also a problem if it's used in a "normal" test class, but in a data provider method.

[driesvints]

@telkins if it's a different problem then this then please open an issue and provide steps to reproduce it, thanks.

[telkins]

And...it looks like this change addresses the issue. (I just updated locally to quickly test to make sure that it works...and it does.)

So...thanks...! :-)

[telkins]

@telkins if it's a different problem then this then please open an issue and provide steps to reproduce it, thanks.

It's exactly the same....I just wanted to confirm that the fix resolved it. I've had issue with data providers in general (because the app isn't up/available) and faker, too...for obvious reasons.

Again...thanks...! :-)