tests/src/Functional/ResourceTestBase.php | 41 +++++++++++++++++--------------
 1 file changed, 22 insertions(+), 19 deletions(-)

diff --git a/tests/src/Functional/ResourceTestBase.php b/tests/src/Functional/ResourceTestBase.php
index 5600c11..8332cce 100644
--- a/tests/src/Functional/ResourceTestBase.php
+++ b/tests/src/Functional/ResourceTestBase.php
@@ -8,6 +8,7 @@ use Drupal\Core\Cache\Cache;
 use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Cache\CacheableResponseInterface;
 use Drupal\Core\Config\Entity\ConfigEntityInterface;
+use Drupal\Core\Entity\ContentEntityNullStorage;
 use Drupal\Core\Entity\FieldableEntityInterface;
 use Drupal\Core\Url;
 use Drupal\field\Entity\FieldConfig;
@@ -110,12 +111,20 @@ abstract class ResourceTestBase extends BrowserTestBase {
   protected $serializer;
 
   /**
+   * The Entity-to-JSON-API service.
+   *
+   * @var \Drupal\jsonapi\EntityToJsonApi
+   */
+  protected $entityToJsonApi;
+
+  /**
    * {@inheritdoc}
    */
   public function setUp() {
     parent::setUp();
 
     $this->serializer = $this->container->get('serializer');
+    $this->entityToJsonApi = $this->container->get('jsonapi.entity.to_jsonapi');
 
     // Ensure the anonymous user role has no permissions at all.
     $user_role = Role::load(RoleInterface::ANONYMOUS_ID);
@@ -811,36 +820,30 @@ abstract class ResourceTestBase extends BrowserTestBase {
 
     // 201 for well-formed request.
     $response = $this->request('POST', $url, $request_options);
-    $this->assertResourceResponse(201, FALSE, $response);
-    if ($has_canonical_url) {
-      $location = $this->entityStorage->load(static::$firstCreatedEntityId)->toUrl('canonical')->setAbsolute(TRUE)->toString();
-      $this->assertSame([$location], $response->getHeader('Location'));
-    }
-    else {
-      $this->assertSame([], $response->getHeader('Location'));
-    }
+    $this->assertResourceResponse(201, FALSE, $response, ['http_response', 'node:2'], $this->getExpectedCacheContexts());
+    // @todo Remove line below in favor of commented line in https://www.drupal.org/project/jsonapi/issues/2878463.
+    $location = Url::fromRoute(sprintf('jsonapi.%s.individual', static::$resourceTypeName), [static::$entityTypeId => $this->entityStorage->load(static::$firstCreatedEntityId)->uuid()])->setAbsolute(TRUE)->toString();
+    //$location = $this->entityStorage->load(static::$firstCreatedEntityId)->toUrl('jsonapi')->setAbsolute(TRUE)->toString();
+    $this->assertSame([$location], $response->getHeader('Location'));
     $this->assertFalse($response->hasHeader('X-Drupal-Cache'));
     // If the entity is stored, perform extra checks.
     if (get_class($this->entityStorage) !== ContentEntityNullStorage::class) {
       // Assert that the entity was indeed created, and that the response body
       // contains the serialized created entity.
       $created_entity = $this->entityStorage->loadUnchanged(static::$firstCreatedEntityId);
-      $created_entity_normalization = $this->serializer->normalize($created_entity, static::$format, ['account' => $this->account]);
+      $created_entity_normalization = $this->entityToJsonApi->normalize($created_entity);
       // @todo Remove this if-test in https://www.drupal.org/node/2543726: execute
       // its body unconditionally.
       if (static::$entityTypeId !== 'taxonomy_term') {
-        $this->assertSame($created_entity_normalization, $this->serializer->decode((string) $response->getBody(), static::$format));
+        $decoded_response_body = $this->serializer->decode((string) $response->getBody(), 'api_json');
+        // @todo Remove the two lines below once https://www.drupal.org/project/jsonapi/issues/2925043 lands.
+        unset($created_entity_normalization['links']);
+        unset($decoded_response_body['links']);
+        $this->assertSame($created_entity_normalization, $decoded_response_body);
       }
       // Assert that the entity was indeed created using the POSTed values.
-      foreach ($this->getNormalizedPostEntity() as $field_name => $field_normalization) {
-        // Some top-level keys in the normalization may not be fields on the
-        // entity (for example '_links' and '_embedded' in the HAL normalization).
-        if ($created_entity->hasField($field_name)) {
-          // Subset, not same, because we can e.g. send just the target_id for the
-          // bundle in a POST request; the response will include more properties.
-          $this->assertArraySubset(static::castToString($field_normalization), $created_entity->get($field_name)
-            ->getValue(), TRUE);
-        }
+      foreach ($this->getNormalizedPostEntity()['data']['attributes'] as $field_name => $field_normalization) {
+        $this->assertSame($field_normalization, $created_entity_normalization['data']['attributes'][$field_name]);
       }
     }
   }