tests/src/Functional/RestJsonApiUnsupported.php | 105 ++++++++++++++++++++++++
 1 file changed, 105 insertions(+)

diff --git a/tests/src/Functional/RestJsonApiUnsupported.php b/tests/src/Functional/RestJsonApiUnsupported.php
new file mode 100644
index 0000000..18e0878
--- /dev/null
+++ b/tests/src/Functional/RestJsonApiUnsupported.php
@@ -0,0 +1,105 @@
+<?php
+
+namespace Drupal\Tests\jsonapi\Functional;
+
+use Drupal\Component\Serialization\Json;
+use Drupal\Core\Url;
+use Drupal\node\Entity\Node;
+use Drupal\node\Entity\NodeType;
+use Drupal\Tests\rest\Functional\AnonResourceTestTrait;
+use Drupal\Tests\rest\Functional\ResourceTestBase;
+
+/**
+ * @group jsonapi
+ */
+class RestJsonApiUnsupported extends ResourceTestBase {
+
+  use AnonResourceTestTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['jsonapi', 'node'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $format = 'api_json';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected static $mimeType = 'application/vnd.api+json';
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUpAuthorization($method) {
+    switch ($method) {
+      case 'GET':
+        $this->grantPermissionsToTestedRole(['access content']);
+        break;
+      default:
+        throw new \UnexpectedValueException();
+    }
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setUp() {
+    parent::setUp();
+
+    // Set up a HTTP client that accepts relative URLs.
+    $this->httpClient = $this->container->get('http_client_factory')
+      ->fromOptions(['base_uri' => $this->baseUrl]);
+
+    // Create a "Camelids" node type.
+    NodeType::create([
+      'name' => 'Camelids',
+      'type' => 'camelids',
+    ])->save();
+
+    // Create a "Llama" node.
+    $node = Node::create(['type' => 'camelids']);
+    $node->setTitle('Llama')
+      ->setOwnerId(0)
+      ->setPublished(TRUE)
+      ->save();
+  }
+
+  /**
+   * Deploying a REST resource using api_json format results in 406 responses.
+   */
+  public function testApiJsonNotSupportedInRest() {
+    $this->assertSame(['json', 'xml'], $this->container->getParameter('serializer.formats'));
+
+    $this->provisionResource('entity.node', ['api_json'], []);
+    $this->setUpAuthorization('GET');
+
+    $url = Node::load(1)->toUrl()
+      ->setOption('query', ['_format' => 'api_json']);
+    $request_options = [];
+
+    $response = $this->request('GET', $url, $request_options);
+    $expected_body = Json::encode([
+      'errors' => [
+        [
+          'title' => 'Not Acceptable',
+          'status' => 406,
+          'detail' => 'Not acceptable format: api_json',
+          'links' => [
+            'info' => 'http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.7',
+          ],
+          'code' => 0,
+        ],
+      ],
+    ]);
+    $this->assertResourceResponse(406, $expected_body, $response);
+  }
+
+  protected function assertNormalizationEdgeCases($method, Url $url, array $request_options) {}
+  protected function getExpectedUnauthorizedAccessMessage($method) {}
+  protected function getExpectedBcUnauthorizedAccessMessage($method) {}
+
+}