incr/tests/Feature/CounterTest.php

<?php

declare(strict_types=1);

namespace Tests\Feature;

use App\Models\Tracker;
use Illuminate\Foundation\Testing\RefreshDatabase;
use PHPUnit\Framework\Attributes\DataProvider;
use Tests\TestCase;

class CounterTest extends TestCase
{
    use RefreshDatabase;

    private function tracker(int $count = 0): Tracker
    {
        return Tracker::factory()->create(['count' => $count]);
    }

    public function test_increment_adds_exactly_one(): void
    {
        $tracker = $this->tracker(5);

        $response = $this->postJson('/increment');

        $response->assertOk()->assertJson(['count' => 6]);
        $this->assertSame(6, $tracker->refresh()->count);
    }

    public function test_increments_accumulate(): void
    {
        $tracker = $this->tracker();

        $this->postJson('/increment');
        $this->postJson('/increment');
        $this->postJson('/increment');

        $this->assertSame(3, $tracker->refresh()->count);
    }

    public function test_increment_returns_404_without_a_tracker(): void
    {
        $this->postJson('/increment')->assertNotFound();
    }

    public function test_count_can_be_set_to_an_absolute_value(): void
    {
        $tracker = $this->tracker(3);

        $response = $this->patchJson('/count', ['count' => 250]);

        $response->assertOk()->assertJson(['count' => 250]);
        $this->assertSame(250, $tracker->refresh()->count);
    }

    public function test_count_can_be_set_to_zero(): void
    {
        $tracker = $this->tracker(42);

        $this->patchJson('/count', ['count' => 0])->assertOk();

        $this->assertSame(0, $tracker->refresh()->count);
    }

    /**
     * @return array<string, array{mixed}>
     */
    public static function invalidCounts(): array
    {
        return [
            'negative' => [-1],
            'non-numeric string' => ['abc'],
            'fractional' => [1.5],
            'above unsigned int ceiling' => [4294967296],
        ];
    }

    #[DataProvider('invalidCounts')]
    public function test_count_rejects_invalid_values(mixed $value): void
    {
        $tracker = $this->tracker(7);

        $this->patchJson('/count', ['count' => $value])
            ->assertStatus(422)
            ->assertJsonValidationErrors('count');

        $this->assertSame(7, $tracker->refresh()->count);
    }

    public function test_count_requires_a_value(): void
    {
        $this->tracker();

        $this->patchJson('/count', [])
            ->assertStatus(422)
            ->assertJsonValidationErrors('count');
    }

    public function test_count_returns_404_without_a_tracker(): void
    {
        $this->patchJson('/count', ['count' => 5])->assertNotFound();
    }

    public function test_counter_endpoints_return_json_not_redirects(): void
    {
        $this->tracker();

        $this->postJson('/increment')
            ->assertOk()
            ->assertHeader('content-type', 'application/json');

        $this->patchJson('/count', ['count' => 1])
            ->assertOk()
            ->assertHeader('content-type', 'application/json');
    }

    public function test_count_is_cast_to_an_integer(): void
    {
        $this->tracker(12);

        $this->assertSame(12, Tracker::first()->count);
    }
}