Add basic injection capabilities to QuarkusTestResourceLifecycleManager

[famod]

Description

As discussed on Zulip, it would come in handy if there was some convenient injection support in QuarkusTestResourceLifecycleManager.
Today you are on own since you only get the testInstance in inject() and you have to do all the hard reflection work yourself.

Implementation ideas

In a backward-compatible way, a new inject(BasicInjector injector) method could be introduced.
That BasicInbjector (or whatever its name is) wraps the test instance and could provide some basic convenience methods like:

• injectIntoFields(Class<?> type, Object value) (or with <T>)
• injectIntoFields(Class<? extends Annotation> type, Object value)
• etc.

[quarkus-bot]

/cc @manovotn, @mkouba

[famod]

/cc @geoand

[geoand]

Thanks for reporting!

This seems pretty useful to me. Hopefully I can pick it up soon

[geoand]

@FroMage always has exquisite API improvement ideas, so let's tap into his knowledge to get another take on this one :)

[geoand]

My idea building on what @famod posted here is something like:

    default void inject(TestInjector testInjector) { // this is the new method

    }

    interface TestInjector { // the implementation will be supplied by the test extension and one new instance will be created per test - the instance will also hold the test object
        
        void injectIntoFields(Object fieldValue, Class<?> fieldType);

        void injectIntoFields(Object fieldValue, Class<?> fieldType, Class<? extends Annotation> annotation); // perhaps we don't need this method at all, and just make the previous one use varargs
    }

Then a supplied user implementations of QuarkusTestResourceLifecycleManager could do something like:

    @Override
    public void inject(TestInjector testInjector) {
        testInjector.injectIntoFields(this.someValue, SomeClass.class);
    }

WDYT?

[famod]

I like the varargs idea. CDI BeanManager and Instance use similar approaches.

PS: Another strategy, which can be used today, is to define an interface with one or more setters etc. and then use the existing inject method that can then simply do an instanceof + cast + call the setter. The rest is up to the implementing test class.
But Quarkus is about developer joy and the injector would make things easier regardless.

[geoand]

#18714 is what I have in mind

[mkouba]

I like the idea but should be really clear that it has nothing to do with CDI injection ;-).

[geoand]

@mkouba definitely. How do you propose we make it clearer?

[mkouba]

@mkouba definitely. How do you propose we make it clearer?

I'm not sure. Maybe just emphasize that the manager is fully in control of the lifecycle of the injected instance and that this "injection" happens after the CDI injection is perfomed??

[geoand]

PR updated to include that note in the Javadoc and the documentation

[FroMage]

@FroMage always has exquisite API improvement ideas, so let's tap into his knowledge to get another take on this one :)

This is perfect!