Part 3: Testing Model Relationships in Laravel — POLYMORPHIC

Part 3: Testing Model Relationships in Laravel — POLYMORPHIC

Source: Better Through Code

This part deals with more complex model relationships, the polymorphic type. Just like before, we shall stick to the official documentation examples and work out befitting tests. To have a low down on the earlier parts see link directly below 👇

• Part 1: Intro and Schema Tests
• Part 2: Testing Basic Model Relationships
• Part 3: Testing Polymorphic Relationships ⏯

POLYMORPHIC RELATIONSHIPS

A polymorphic relationship allows a target model to belong to more than one type of model using a single association.  — Laravel.com

1. One-to-One Polymorphic Relationship

A one-to-one polymorphic relation is similar to a simple one-to-one relation; however, the target model can belong to more than one type of model on a single association.

Scenario:

A blog Post and a User may share a polymorphic relation to an Image model. Using a one-to-one polymorphic relation allows you to have a single list of unique images that are used for both blog post s and user accounts

morphTo()

— An image table can be morph ed in to any model (i.e serve many different models), eg User or Post model in our case.

// App/Image.php
...
public function imageable() 
{ 
 return $this->morphTo(); 
}

	<?php
	namespace Tests\Unit;
	use App\Country;
	use App\Image;
	use App\Post;
	use App\Supplier;
	use App\User;
	use Illuminate\Foundation\Testing\RefreshDatabase;
	use Illuminate\Foundation\Testing\WithFaker;
	use Illuminate\Support\Facades\Schema;
	use Tests\TestCase;
	class ImagesTest extends TestCase
	{
	use RefreshDatabase, WithFaker;
	public function setUp() :void
	{
	parent::setUp();
	$this->country = factory(Country::class)->create();
	$this->supplier = factory(Supplier::class)->create();
	$this->user = factory(User::class)->create();
	$this->post = factory(Post::class)->create();
	$this->image = factory(Image::class)->create();
	}
	/** @test */
	public function images_database_has_expected_columns()
	{
	$this->assertTrue(Schema::hasColumns('images', [
	'id', "url", "imageable_id", "imageable_type"
	]), 1);
	}
	/** @test */
	public function an_image_can_be_uploaded_by_a_user() // morphedTo a USER
	{
	$image = factory(Image::class)->create([
	"imageable_id" => $this->user->id,
	"imageable_type" => "App\User",
	]);
	$this->assertInstanceOf(User::class, $image->imageable);
	}
	/** @test */
	public function an_image_can_be_uploaded_for_a_post() // morphedTo a POST
	{
	$image = factory(Image::class)->create([
	"imageable_id" => $this->post->id,
	"imageable_type" => "App\Post",
	]);
	$this->assertInstanceOf(Post::class, $image->imageable);
	}
	}

view raw morphTo_test.php hosted with ❤ by GitHub

morphOne()

• — A user/post model can morph one instance of the same image model table (i.e make use of same image table but one record per user/post).
• — INVERSE of morphTo relationship.

// App/User.php
...
public function image() 
{ 
 return $this->morphOne(Image::class, 'imageable'); 
}

	<?php
	namespace Tests\Unit;
	use App\Country;
	use App\Image;
	use App\Post;
	use App\Supplier;
	use App\User;
	use Illuminate\Foundation\Testing\RefreshDatabase;
	use Illuminate\Foundation\Testing\WithFaker;
	use Illuminate\Support\Facades\Schema;
	use Tests\TestCase;
	class UserTest extends TestCase
	{
	use RefreshDatabase, WithFaker;
	public function setUp() :void
	{
	parent::setUp();
	$this->country = factory(Country::class)->create();
	$this->supplier = factory(Supplier::class)->create();
	$this->user = factory(User::class)->create();
	$this->post = factory(Post::class)->create();
	$this->image = factory(Image::class)->create([
	"imageable_id" => $this->user->id,
	"imageable_type" => "App\User",
	]);
	}
	// ...
	/** @test */
	public function a_user_morphs_one_image()
	{
	$this->assertInstanceOf(Image::class, $this->user->image);
	}
	}

view raw morphOne_test.php hosted with ❤ by GitHub

Files relevant to this test 👇

- **MODEL FILES(App/)
 -- User.php 
 -- Post.php
 -- Image.php

- **MIGRATION FILES(database/migrations/)
 -- 2014\10\12\000000\create\users\table.php
 -- 2019\09\27\100604\create\posts\table.php
 -- 2019\09\28\143143\create\images\table.php

- **MODEL FACTORY FILES(database/factories/)
 -- UserFactory.php 
 -- PostFactory.php
 -- ImageFactory.php

- **UNIT TEST FILES(tests/Units/)
 -- UserTest.php 
 -- PostsTest.php
 -- ImagesTest.php

2. One-to-Many (Polymorphic)

A “one-to-many polymorphic” relation is similar to a simple one-to-many relation; however, the target model can belong to more than one type of model on a single association. — Laravel.com

Scenario:

Users of your application can “comment” on both posts and videos. Using polymorphic relationships, you may use a single comments table for both of these scenarios.

morphTo()

— A comment table can be morph ed to any model (i.e serve many different models), eg Video or Post model in our case.

// App/Comment.php
...
public function commentable() 
{ 
 return $this->morphTo(); 
}

	<?php
	namespace Tests\Unit;
	use App\Comment;
	use App\Country;
	use App\Post;
	use App\Supplier;
	use App\User;
	use App\Video;
	use Illuminate\Foundation\Testing\RefreshDatabase;
	use Illuminate\Foundation\Testing\WithFaker;
	use Illuminate\Support\Facades\Schema;
	use Tests\TestCase;
	class CommentsTest extends TestCase
	{
	use RefreshDatabase, WithFaker;
	public function setUp() :void
	{
	parent::setUp();
	$this->country = factory(Country::class)->create();
	$this->supplier = factory(Supplier::class)->create();
	$this->user = factory(User::class)->create();
	$this->post = factory(Post::class)->create();
	$this->video = factory(Video::class)->create();
	$this->comment = factory(Comment::class)->create();
	}
	// ...
	/** @test */
	public function a_comment_can_be_morphed_to_a_video_model()
	{
	$comment = factory(Comment::class)->create([
	"commentable_id" => $this->video->id,
	"commentable_type" => "App\Video",
	]);
	$this->assertInstanceOf(Video::class, $comment->commentable);
	}
	/** @test */
	public function a_comment_can_be_morphed_to_a_post_model()
	{
	$comment = factory(Comment::class)->create([
	"commentable_id" => $this->post->id,
	"commentable_type" => "App\Post",
	]);
	$this->assertInstanceOf(Post::class, $comment->commentable);
	}
	}

view raw morphTo_poly_test.php hosted with ❤ by GitHub

morphMany()

• — A video/post model can morph many instances of the same comment model table (i.e make use of same comment table for many records).
• — INVERSE of morphTo relationship.

// App/Video.php
...
public function comments() 
{ 
 return $this->morphMany(Comment::class, 'commentable'); 
}

	<?php
	namespace Tests\Unit;
	use App\Comment;
	use App\Country;
	use App\Post;
	use App\Supplier;
	use App\User;
	use App\Video;
	use Tests\TestCase;
	use Illuminate\Foundation\Testing\WithFaker;
	use Illuminate\Foundation\Testing\RefreshDatabase;
	use Illuminate\Support\Facades\Schema;
	class VideosTest extends TestCase
	{
	use RefreshDatabase, WithFaker;
	public function setUp() :void
	{
	parent::setUp();
	$this->country = factory(Country::class)->create();
	$this->supplier = factory(Supplier::class)->create();
	$this->user = factory(User::class)->create();
	$this->post = factory(Post::class)->create(['user_id' => $this->user->id]);
	$this->video = factory(Video::class)->create(['user_id' => $this->user->id]);
	$this->comment = factory(Comment::class)->create([
	"commentable_id" => $this->video->id,
	"commentable_type" => "App\Video",
	]);
	}
	/** @test */
	public function videos_database_has_expected_columns()
	{
	$this->assertTrue(
	Schema::hasColumns('videos', [
	'id','user_id', 'title', 'description', 'size', 'length'
	]), 1);
	}
	/** @test */
	public function a_video_morphs_many_comments()
	{
	$this->assertInstanceOf('Illuminate\Database\Eloquent\Collection', $this->video->comments);
	}
	}

view raw morphMany_poly_test.php hosted with ❤ by GitHub

Files relevant to this test 👇

**MODEL FILES(App/)

-- User.php 

-- Post.php

-- Video.php

-- Comment.php
**MIGRATION FILES(database/migrations/)

-- 2019\09\28\211240\create\videos\table.php

-- 2019\09\28\221627\add\commentable\id\and\commentable\type\to\comments\table.php
**MODEL FACTORY FILES(database/factories/)

-- VideoFactory.php
**UNIT TEST FILES(tests/Unit/)

-- PostsTest.php

-- VideosTest.php

-- CommentsTest.php

1. Many-to-Many (Polymorphic)

In progress…

Kindly check back soon

• 👉Part 1: Intro and Schema Tests
• 👉Part 2: Testing Basic Model Relationships
• ⏯Part 3: Testing Polymorphic Relationships

Comments

[robencom]

Hello, many thanks for these articles!
I appreciate it!
Waiting for the next one: "Many-to-Many (Polymorphic)".