Get registered media collections (#1976)

* Add `getRegisteredMediaCollections()` and supporting test

* Add explanation/usage to docs

docs/working-with-media-collections/defining-media-collections.md

@@ -23,6 +23,16 @@ public function registerMediaCollections(): void
 }
 ```
 
+## Getting registered media collections
+
+To retrieve all registered media collections on your model you can use the `getRegisteredMediaCollections` method.  
+
+```php
+$mediaCollections = $yourModel->getRegisteredMediaCollections();
+```
+
+This returns a collection of `MediaCollection` objects.
+
 ## Defining a fallback URL or path
 
 If your media collection does not contain any items, calling `getFirstMediaUrl` or `getFirstMediaPath` will return `null`. You can change this by setting a fallback url and/or path using `useFallbackUrl` and `useFallbackPath`.

src/InteractsWithMedia.php

@@ -294,6 +294,13 @@ public function getFirstTemporaryUrl(
         return $media->getTemporaryUrl($expiration, $conversionName);
     }
 
+    public function getRegisteredMediaCollections(): Collection
+    {
+        $this->registerMediaCollections();
+
+        return collect($this->mediaCollections);
+    }
+
     public function getMediaCollection(string $collectionName = 'default'): ?MediaCollection
     {
         $this->registerMediaCollections();

tests/MediaCollections/MediaCollectionTest.php

@@ -2,6 +2,7 @@
 
 namespace Spatie\MediaLibrary\Tests\MediaCollections;
 
+use Spatie\MediaLibrary\MediaCollections\MediaCollection;
 use Spatie\MediaLibrary\MediaCollections\Models\Media;
 use Spatie\MediaLibrary\Tests\TestCase;
 
@@ -30,4 +31,16 @@ public function it_can_get_the_sum_of_all_media_item_sizes()
 
         $this->assertEquals($mediaItem->size + $anotherMediaItem->size, $totalSize);
     }
+
+    /** @test */
+    public function it_can_get_registered_media_collections()
+    {
+        // the 'avatar' media collection is registered in
+        // \Spatie\MediaLibrary\Tests\TestSupport\TestModels\TestModel->registerMediaCollections()
+        $collections = $this->testModel->getRegisteredMediaCollections();
+
+        $this->assertCount(1, $collections);
+        $this->assertInstanceOf(MediaCollection::class, $collections->first());
+        $this->assertEquals('avatar', $collections->first()->name);
+    }
 }