Repository is supposed to generate IDs

More/Repository/Domain/Post.php

@@ -5,7 +5,7 @@ namespace DesignPatterns\More\Repository\Domain;
 class Post
 {
     /**
-     * @var int|null
+     * @var int
      */
     private $id;
 
@@ -19,6 +19,15 @@ class Post
      */
     private $text;
 
+    public static function draft(int $id, string $title, string $text): Post
+    {
+        return new self(
+            $id,
+            $title,
+            $text
+        );
+    }
+
     public static function fromState(array $state): Post
     {
         return new self(
@@ -29,22 +38,17 @@ class Post
     }
 
     /**
-     * @param int|null $id
+     * @param int $id
      * @param string $text
      * @param string $title
      */
-    public function __construct($id, string $title, string $text)
+    private function __construct(int $id, string $title, string $text)
     {
         $this->id = $id;
         $this->text = $text;
         $this->title = $title;
     }
 
-    public function setId(int $id)
-    {
-        $this->id = $id;
-    }
-
     public function getId(): int
     {
         return $this->id;

More/Repository/MemoryStorage.php

@@ -14,20 +14,22 @@ class MemoryStorage implements Storage
      */
     private $lastId = 0;
 
-    public function persist(array $data): int
+    public function generateId(): int
     {
         $this->lastId++;
 
-        $data['id'] = $this->lastId;
-        $this->data[$this->lastId] = $data;
-
         return $this->lastId;
     }
 
+    public function persist(array $data)
+    {
+        $this->data[$this->lastId] = $data;
+    }
+
     public function retrieve(int $id): array
     {
         if (!isset($this->data[$id])) {
-            throw new \OutOfRangeException(sprintf('No data found for ID %d', $id));
+            throw new \OutOfBoundsException(sprintf('No data found for ID %d', $id));
         }
 
         return $this->data[$id];
@@ -36,7 +38,7 @@ class MemoryStorage implements Storage
     public function delete(int $id)
     {
         if (!isset($this->data[$id])) {
-            throw new \OutOfRangeException(sprintf('No data found for ID %d', $id));
+            throw new \OutOfBoundsException(sprintf('No data found for ID %d', $id));
         }
 
         unset($this->data[$id]);

More/Repository/PostRepository.php

@@ -25,12 +25,17 @@ class PostRepository
         $this->persistence = $persistence;
     }
 
+    public function generateId(): int
+    {
+        return $this->persistence->generateId();
+    }
+
     public function findById(int $id): Post
     {
+        try {
             $arrayData = $this->persistence->retrieve($id);
-
+        } catch (\OutOfBoundsException $e) {
-        if (is_null($arrayData)) {
+            throw new \OutOfBoundsException(sprintf('Post with id %d does not exist', $id), 0, $e);
-            throw new \InvalidArgumentException(sprintf('Post with ID %d does not exist', $id));
         }
 
         return Post::fromState($arrayData);
@@ -38,11 +43,10 @@ class PostRepository
 
     public function save(Post $post)
     {
-        $id = $this->persistence->persist([
+        $this->persistence->persist([
+            'id' => $post->getId(),
             'text' => $post->getText(),
             'title' => $post->getTitle(),
         ]);
-
-        $post->setId($id);
     }
 }

More/Repository/Storage.php

@@ -4,7 +4,9 @@ namespace DesignPatterns\More\Repository;
 
 interface Storage
 {
-    public function persist(array $data): int;
+    public function generateId(): int;
+
+    public function persist(array $data);
 
     public function retrieve(int $id): array;
 

More/Repository/Tests/PostRepositoryTest.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace DesignPatterns\More\Repository\Tests;
+
+use DesignPatterns\More\Repository\MemoryStorage;
+use DesignPatterns\More\Repository\Domain\Post;
+use DesignPatterns\More\Repository\PostRepository;
+use PHPUnit\Framework\TestCase;
+
+class PostRepositoryTest extends TestCase
+{
+    /**
+     * @var PostRepository
+     */
+    private $repository;
+
+    protected function setUp()
+    {
+        $this->repository = new PostRepository(new MemoryStorage());
+    }
+
+    public function testCanGenerateId()
+    {
+        $this->assertEquals(1, $this->repository->generateId());
+    }
+
+    /**
+     * @expectedException \OutOfBoundsException
+     * @expectedExceptionMessage Post with id 42 does not exist
+     */
+    public function testThrowsExceptionWhenTryingToFindPostWhichDoesNotExist()
+    {
+        $this->repository->findById(42);
+    }
+
+    public function testCanPersistPostDraft()
+    {
+        $postId = $this->repository->generateId();
+        $post = Post::draft($postId, 'Repository Pattern', 'Design Patterns PHP');
+        $this->repository->save($post);
+
+        $this->assertEquals($postId, $this->repository->findById($postId)->getId());
+    }
+}

More/Repository/Tests/RepositoryTest.php

@@ -1,22 +0,0 @@
-<?php
-
-namespace DesignPatterns\More\Repository\Tests;
-
-use DesignPatterns\More\Repository\MemoryStorage;
-use DesignPatterns\More\Repository\Domain\Post;
-use DesignPatterns\More\Repository\PostRepository;
-use PHPUnit\Framework\TestCase;
-
-class RepositoryTest extends TestCase
-{
-    public function testCanPersistAndFindPost()
-    {
-        $repository = new PostRepository(new MemoryStorage());
-        $post = new Post(null, 'Repository Pattern', 'Design Patterns PHP');
-
-        $repository->save($post);
-
-        $this->assertEquals(1, $post->getId());
-        $this->assertEquals($post->getId(), $repository->findById(1)->getId());
-    }
-}