[Live] add test helper

[kbond]

Q	A
Bug fix?	no
New feature?	yes
Tickets	Continuation of #821
License	MIT

use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
use Symfony\UX\LiveComponent\Test\InteractsWithLiveComponents;

class MyComponentTest extends KernelTestCase
{
    use InteractsWithLiveComponents;

    public function testThisComponent(): void
    {
        $testComponent = $this->createLiveComponent('my_component');
        $testComponent = $this->createLiveComponent(Component::class); // or use the FQCN
        
        (string) $testComponent->render(); // string - initial state html
        $testComponent->component(); // object - component instance at initial state
        
        $testComponent
            ->call('increase') // call a live action
            ->call('increase', ['amount' => 2]) // call a live action with arguments
            ->set('count', 5) // set a live prop
            ->emit('inceaseEvent') // emit a live event
            ->emit('inceaseEvent', ['amount' => 2]) // emit a live event with arguments
            ->refresh() // simply refresh the component
        ;
        
        (string) $testComponent->render(); // string - updated state html
        $testComponent->component(); // object - component instance at updated state

        /** @var Symfony\Component\HttpFoundation\Response $response */
        $response = $testComponent->call('actionThatRedirects')->response();
    }
}

TODO:

• handle action responses
• ->refresh() method?
• Docs
• Changelog

[kbond]

Again, with the system I describe in #818 (comment), we could make a really nice chainable test experience:

$this->createLiveComponent('my_component')
    ->assertSeeIn('div.count', 1)
    ->call('increase')
    ->assertSeeIn('div.count', 2)
    ->call('increase', ['amount' => 3])
    ->assertSeeIn('div.count', 5)
;

[WebMamba]

Hey @kbond, I am using this PR a lot to test my component and it's working great! Do you need a hand in order to finish it?

[kbond]

I am using this PR a lot to test my component and it's working great! Do you need a hand in order to finish it?

I was really just waiting for this feedback! Think it's current state is enough to start?

[WebMamba]

Think it's current state is enough to start?

I guess, I mean I didn't have a complex need yet but for my current need, it's working perfectly fine.

[kbond]

Ok, I'll add refresh()/response() methods + docs and I think we should be good to go here.

[kbond]

Ok, I believe this to be ready!

I also added 586a572 but can move to another PR if desired.

[weaverryan]

Thank you Kevin!