TIDE/backend/tests/Unit/Post/UseCases/ListRecentPostsTest.php

<?php

namespace Tests\Unit\Post\UseCases;

use App\Exceptions\BadRequestException;
use App\Post\CreatePostDto;
use App\Post\UseCases\ListRecentPosts\ListRecentPosts;
use App\Post\UseCases\ListRecentPosts\ListRecentPostsRequest;
use DateTimeImmutable;
use DateTimeZone;
use Tests\Fakes\FakePostRepository;
use Tests\TestCase;

class ListRecentPostsTest extends TestCase
{
    private FakePostRepository $postRepo;

    private DateTimeImmutable $now;

    private ListRecentPosts $useCase;

    protected function setUp(): void
    {
        $this->now = new DateTimeImmutable(
            '2026-05-06T12:00:00',
            new DateTimeZone('UTC')
        );
        $this->postRepo = new FakePostRepository;
        $this->useCase = new ListRecentPosts($this->postRepo);
    }

    private function seedPost(int $userId, string $title, string $offset): void
    {
        $this->postRepo->create(new CreatePostDto(
            userId: $userId,
            title: $title,
            body: 'body',
            createdAt: $this->now->modify($offset),
        ));
    }

    public function test_zero_limit_throws_bad_request(): void
    {
        $this->expectException(BadRequestException::class);
        $this->useCase->execute(new ListRecentPostsRequest(limit: 0));
    }

    public function test_negative_limit_throws_bad_request(): void
    {
        $this->expectException(BadRequestException::class);
        $this->useCase->execute(new ListRecentPostsRequest(limit: -1));
    }

    public function test_empty_repo_returns_empty_array(): void
    {
        $posts = $this->useCase->execute(
            new ListRecentPostsRequest(limit: 10)
        );

        $this->assertSame([], $posts);
    }

    public function test_returns_posts_ordered_newest_first(): void
    {
        $this->seedPost(1, 'oldest', '-2 days');
        $this->seedPost(2, 'middle', '-1 day');
        $this->seedPost(3, 'newest', '-1 hour');

        $posts = $this->useCase->execute(
            new ListRecentPostsRequest(limit: 10)
        );

        $this->assertCount(3, $posts);
        $this->assertSame('newest', $posts[0]->getTitle());
        $this->assertSame('middle', $posts[1]->getTitle());
        $this->assertSame('oldest', $posts[2]->getTitle());
    }

    public function test_respects_limit(): void
    {
        $this->seedPost(1, 'first', '-3 days');
        $this->seedPost(2, 'second', '-2 days');
        $this->seedPost(3, 'third', '-1 day');
        $this->seedPost(4, 'fourth', '-1 hour');

        $posts = $this->useCase->execute(
            new ListRecentPostsRequest(limit: 2)
        );

        $this->assertCount(2, $posts);
        $this->assertSame('fourth', $posts[0]->getTitle());
        $this->assertSame('third', $posts[1]->getTitle());
    }
}