Correct docblocks, add api-functional test

Author: austris-argalis

app/code/Magento/CatalogGraphQl/Model/Resolver/Product/CanonicalUrl.php

@@ -14,6 +14,9 @@
 use Magento\Framework\GraphQl\Query\ResolverInterface;
 use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
 
+/**
+ * Resolve data for product canonical URL
+ */
 class CanonicalUrl implements ResolverInterface
 {
     /**
@@ -31,15 +34,7 @@ public function __construct(
     }
 
     /**
-     * Fetches the data from persistence models and format it according to the GraphQL schema.
-     *
-     * @param \Magento\Framework\GraphQl\Config\Element\Field $field
-     * @param $context
-     * @param ResolveInfo $info
-     * @param array|null $value
-     * @param array|null $args
-     * @throws \Exception
-     * @return Value
+     * {@inheritdoc}
      */
     public function resolve(
         Field $field,

app/code/Magento/CatalogGraphQl/Test/Integration/Model/ProductsTest.php

@@ -227,6 +227,7 @@ public function testQueryAllFieldsSimpleProduct()
             updated_at
             url_key
             url_path
+            canonical_url
             websites { id name code sort_order default_group_id is_default }
             ... on PhysicalProductInterface {
                 weight
@@ -272,6 +273,10 @@ public function testQueryAllFieldsSimpleProduct()
             'Filter category',
             $responseObject->getData('products/items/0/categories/2/name')
         );
+        self::assertEquals(
+            $product->getUrlModel()->getUrl($product, ['_ignore_category' => true, '_nosid' => true]),
+            $responseObject->getData('products/items/0/canonical_url')
+        );
     }
 
     /**