diff --git a/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
index c72f065..a00cd92 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
@@ -424,7 +424,11 @@ public function testGet() {
 
     // DX: upon deprovisioning, immediate 404, or 403 if canonical route.
     $response = $this->request('GET', $url, $request_options);
-    $this->assertSame($has_canonical_url ? 403 : 404, $response->getStatusCode());
+    // In case we have a canonical URL, this will render the normal response.
+    // As we request for a specific format, and there is no REST resource
+    // provided we get back a 406. In case we don't have any canonical URL we
+    // will not find any route.
+    $this->assertSame($has_canonical_url ? 406 : 404, $response->getStatusCode());
 
 
     $this->provisionEntityResource();