ContentsStorer example

class ContentsStorerTest extends TestCase
{
    private ContentsStorer $storer;

    protected function setUp(): void
    {
        Feature::skipTestIfActive('v6.6.0.0', $this);

        $this->storer = new ContentsStorer();
    }

    public function testStoreWithAware(): void
    {
        $event = $this->createMock(MailSentEvent::class);
        $stored = [];
        $stored = $this->storer->store($event, $stored);
        static::assertArrayHasKey(ContentsAware::CONTENTS, $stored);
    }

    public function testStoreWithNotAware(): void
    {