Súbehy na reálnej databáze

use Illuminate\Support\Facades\DB;
use RoundlyConsulting\Testing\Concurrency\Racer;

it('serialises two redemptions of the last coupon', function (): void {
    DB::beginTransaction();
    Coupon::query()->lockForUpdate()->find($coupon->id);

    $racer = (new Racer)
        ->run(fn (): string => Coupons::redeem($coupon->code) ? 'redeemed' : 'refused')
        ->waitUntilBlockedOrDone();

    Coupons::redeem($coupon->code);
    DB::commit();

    expect($racer->outcome())->toBe('refused');
})->skip(fn (): bool => ! Racer::available(), 'needs a real engine and pcntl + posix');

it('waits until the racer blocks on a row the parent holds, then lets it through', function (): void {
    DB::table('race_rows')->insert(['id' => 1, 'value' => 1]);

    DB::beginTransaction();
    DB::table('race_rows')->where('id', 1)->lockForUpdate()->first();

    $racer = (new Racer)->run(function (): string {
        DB::table('race_rows')->where('id', 1)->update(['value' => 2]);

        return 'updated';
    })->waitUntilBlockedOrDone();

    // Blocked, not finished: the row is still the parent's.
    expect(DB::table('race_rows')->value('value'))->toBe(1);

    DB::commit();

    expect($racer->outcome())->toBe('updated')
        ->and(DB::table('race_rows')->value('value'))->toBe(2);
})->skip(fn (): bool => ! Racer::available(), 'needs a real engine (pgsql/mysql) and pcntl + posix');

(new Racer)->run(fn (): string => 'won')->outcome();
// 'won'

(new Racer)->run(fn (): string => throw new RuntimeException('lost the race'))->outcome();
// 'error: RuntimeException: lost the race'

(new Racer)->run(function (): string { exit(0); })->outcome();
// 'error: the racer exited without reporting an outcome'

(new Racer)->run(fn (): string => '')->outcome();
// '' — an empty outcome stays apart from a racer that never reported

$racer = (new Racer)->run(function (): string {
    sleep(30);

    return 'too late';
});
$racer->waitUntilBlockedOrDone(timeoutSeconds: 0.3);
// throws RuntimeException: The racer neither blocked nor finished within 0.3 s.
// $racer->outcome() then starts with 'error: the racer was killed'