test ClearFeaturedPost use case

backend/tests/Unit/Post/UseCases/ClearFeaturedPostTest.php

@@ -0,0 +1,95 @@
+<?php
+
+namespace Tests\Unit\Post\UseCases;
+
+use App\Exceptions\BadRequestException;
+use App\Exceptions\ForbiddenException;
+use App\Post\CreatePostDto;
+use App\Post\Post;
+use App\Post\UseCases\ClearFeaturedPost\ClearFeaturedPost;
+use App\Post\UseCases\ClearFeaturedPost\ClearFeaturedPostRequest;
+use DateTimeImmutable;
+use DateTimeZone;
+use Tests\Fakes\FakePostRepository;
+use Tests\TestCase;
+
+class ClearFeaturedPostTest extends TestCase
+{
+    private FakePostRepository $postRepo;
+
+    private ClearFeaturedPost $useCase;
+
+    private DateTimeImmutable $now;
+
+    protected function setUp(): void
+    {
+        $this->now = new DateTimeImmutable(
+            '2026-05-06T12:00:00',
+            new DateTimeZone('UTC'),
+        );
+        $this->postRepo = new FakePostRepository;
+        $this->useCase = new ClearFeaturedPost($this->postRepo);
+    }
+
+    private function seedFeaturedPost(int $slot): Post
+    {
+        $post = $this->postRepo->create(new CreatePostDto(
+            userId: 1,
+            title: 'A',
+            body: 'B',
+            createdAt: $this->now,
+        ));
+
+        return $this->postRepo->update(new Post(
+            id: $post->getId(),
+            userId: $post->getUserId(),
+            title: $post->getTitle(),
+            body: $post->getBody(),
+            createdAt: $post->getCreatedAt(),
+            featureSlot: $slot,
+        ));
+    }
+
+    public function test_non_admin_throws_forbidden(): void
+    {
+        $post = $this->seedFeaturedPost(1);
+        $this->expectException(ForbiddenException::class);
+        $this->useCase->execute(new ClearFeaturedPostRequest(
+            postId: $post->getId(),
+            requesterIsAdmin: false,
+        ));
+    }
+
+    public function test_zero_post_id_throws_bad_request(): void
+    {
+        $this->expectException(BadRequestException::class);
+        $this->useCase->execute(new ClearFeaturedPostRequest(
+            postId: 0,
+            requesterIsAdmin: true,
+        ));
+    }
+
+    public function test_unknown_post_is_no_op(): void
+    {
+        $this->useCase->execute(new ClearFeaturedPostRequest(
+            postId: 999,
+            requesterIsAdmin: true,
+        ));
+
+        $this->assertNull($this->postRepo->find(999));
+    }
+
+    public function test_admin_clears_feature_slot(): void
+    {
+        $post = $this->seedFeaturedPost(2);
+
+        $this->useCase->execute(new ClearFeaturedPostRequest(
+            postId: $post->getId(),
+            requesterIsAdmin: true,
+        ));
+
+        $this->assertNull(
+            $this->postRepo->find($post->getId())->getFeatureSlot(),
+        );
+    }
+}