diff --git a/src/Entity/Post.php b/src/Entity/Post.php
index d2f968b..0b54550 100644
--- a/src/Entity/Post.php
+++ b/src/Entity/Post.php
@@ -2,6 +2,7 @@
 
 namespace App\Entity;
 
+use ApiPlatform\Doctrine\Orm\Filter\SearchFilter;
 use ApiPlatform\Metadata;
 use ApiPlatform\Metadata\ApiProperty;
 use ApiPlatform\Metadata\ApiResource;
@@ -18,6 +19,7 @@ use Symfony\Component\Serializer\Attribute\Groups;
     normalizationContext: ['groups' => ['post:collection:read', 'post:read']],
 )]
 #[GetCollection(normalizationContext: ['groups' => ['post:collection:read']])]
+#[Metadata\ApiFilter(filterClass: SearchFilter::class, properties: ['species' => 'exact'])]
 class Post
 {
     #[ORM\Id]
@@ -149,6 +151,8 @@ class Post
     #[ORM\PreUpdate]
     public function setPublicationDateValue(): void
     {
-        $this->publicationDate = new \DateTimeImmutable();
+        if ($this->publicationDate === null) {
+            $this->publicationDate = new \DateTimeImmutable();
+        }
     }
 }
diff --git a/tests/Api/PostApiTest.php b/tests/Api/PostApiTest.php
new file mode 100644
index 0000000..9304115
--- /dev/null
+++ b/tests/Api/PostApiTest.php
@@ -0,0 +1,114 @@
+<?php
+
+namespace App\Tests\Api;
+
+use ApiPlatform\Symfony\Bundle\Test\ApiTestCase;
+use App\Entity\Post;
+use App\Entity\Species;
+
+class PostApiTest extends ApiTestCase
+{
+    private int $speciesId;
+    private int $postId;
+
+    protected function setUp(): void
+    {
+        $kernel = self::bootKernel();
+        $manager = $kernel->getContainer()->get('doctrine')->getManager();
+        $species = (new Species())
+            ->setVernacularName('Oak')
+            ->setScientificName('Quercus')
+            ->setRegion('Europe');
+        $post = (new Post())
+            ->setPublicationDate(new \DateTimeImmutable('2024-06-07'))
+            ->setFoundDate(new \DateTimeImmutable('2024-06-06'))
+            ->setCommentary("maple")
+            ->setSpecies($species);
+        $manager->persist($species);
+        $manager->persist($post);
+        $manager->flush();
+        $this->speciesId = $species->getId();
+        $this->postId = $post->getId();
+    }
+
+    public function testFindInSpecies(): void
+    {
+        $response = static::createClient()->request('GET', '/api/species/' . $this->speciesId);
+
+        $this->assertResponseIsSuccessful();
+        $this->assertJsonEquals([
+            '@context' => '/api/contexts/Species',
+            '@id' => '/api/species/' . $this->speciesId,
+            '@type' => 'Species',
+            'id' => $this->speciesId,
+            'vernacular_name' => 'Oak',
+            'scientific_name' => 'Quercus',
+            'region' => 'Europe',
+            'posts' => ['/api/posts/' . $this->postId],
+        ]);
+    }
+
+    public function testGetExisting(): void
+    {
+        $response = static::createClient()->request('GET', '/api/posts/' . $this->postId);
+
+        $this->assertResponseIsSuccessful();
+        $this->assertJsonEquals([
+            '@context' => '/api/contexts/Post',
+            '@id' => '/api/posts/' . $this->postId,
+            '@type' => 'Post',
+            'id' => $this->postId,
+            'foundDate' => '2024-06-06T00:00:00+00:00',
+            'publicationDate' => '2024-06-07T00:00:00+00:00',
+            'commentary' => 'maple',
+            'species' => '/api/species/' . $this->speciesId,
+        ]);
+    }
+
+    public function testFilterBySpecies(): void
+    {
+        $response = static::createClient()->request('GET', '/api/posts', [
+            'query' => [
+                'species' => $this->speciesId,
+            ],
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $this->assertJsonContains([
+            '@context' => '/api/contexts/Post',
+            '@id' => '/api/posts',
+            '@type' => 'hydra:Collection',
+            'hydra:totalItems' => 1,
+            'hydra:member' => [
+                [
+                    '@type' => 'Post',
+                    'id' => $this->postId,
+                    'foundDate' => '2024-06-06T00:00:00+00:00',
+                    'species' => '/api/species/' . $this->speciesId,
+                ],
+            ],
+        ]);
+    }
+
+    public function testPostSetPublicationDate(): void
+    {
+        $response = static::createClient()->request('POST', '/api/posts', [
+            'json' => [
+                'foundDate' => '2024-06-06',
+                'publicationDate' => '2024-06-07',
+                'commentary' => 'maple',
+                'species' => '/api/species/' . $this->speciesId,
+            ],
+        ]);
+
+        $this->assertResponseIsSuccessful();
+        $this->assertJsonContains([
+            '@context' => '/api/contexts/Post',
+            '@type' => 'Post',
+            'foundDate' => '2024-06-06T00:00:00+00:00',
+            'commentary' => 'maple',
+            'species' => '/api/species/' . $this->speciesId,
+        ]);
+        $this->assertArrayHasKey('publicationDate', $response->toArray(false));
+    }
+}