.../EntityResource/EntityResourceTestBase.php      | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
index 6ec50fc..df66131 100644
--- a/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/EntityResource/EntityResourceTestBase.php
@@ -596,7 +596,8 @@ public function testPost() {
     $request_options = [];
 
 
-    // DX: 404 when resource not provisioned. HTML because no ?_format.
+    // DX: 404 when resource not provisioned. HTML response because missing
+    // ?_format query string.
     $response = $this->request('POST', $url, $request_options);
     $this->assertSame(404, $response->getStatusCode());
     $this->assertSame(['text/html; charset=UTF-8'], $response->getHeader('Content-Type'));
@@ -615,7 +616,8 @@ public function testPost() {
     $url->setOption('query', []);
 
 
-    // DX: 415 when no Content-Type request header. HTML because no ?_format.
+    // DX: 415 when no Content-Type request header. HTML response because
+    // missing ?_format query string.
     $response = $this->request('POST', $url, $request_options);
     $this->assertSame(415, $response->getStatusCode());
     $this->assertSame(['text/plain; charset=UTF-8'], $response->getHeader('Content-Type'));
@@ -772,7 +774,8 @@ public function testPatch() {
     $request_options = [];
 
 
-    // DX: 405 if canonical route, 404 for non canonical. HTML because no ?_format.
+    // DX: 404 when resource not provisioned, 405 if canonical route. Plain text
+    // or HTML response because missing ?_format query string.
     $response = $this->request('PATCH', $url, $request_options);
     if ($has_canonical_url) {
       $this->assertSame(405, $response->getStatusCode());
@@ -788,11 +791,10 @@ public function testPatch() {
     $url->setOption('query', ['_format' => static::$format]);
 
 
-    // DX: 405 when resource not provisioned. 404 for non canonical.
+    // DX: 404 when resource not provisioned, 405 if canonical route.
     $response = $this->request('PATCH', $url, $request_options);
     if ($has_canonical_url) {
-      $this->assertSame(405, $response->getStatusCode());
-      $this->assertSame(['GET, POST, HEAD'], $response->getHeader('Allow'));
+      $this->assertResourceErrorResponse(405, 'No route found for "PATCH ' . str_replace($this->baseUrl, '', $this->getUrl()->setAbsolute()->toString()) . '": Method Not Allowed (Allow: GET, POST, HEAD)', $response);
     }
     else {
       $this->assertResourceErrorResponse(404, 'No route found for "PATCH ' . str_replace($this->baseUrl, '', $this->getUrl()->setAbsolute()->toString()) . '"', $response);
@@ -967,7 +969,8 @@ public function testDelete() {
     $request_options = [];
 
 
-    // DX: 405 when resource not provisioned. 404 for non canonical.
+    // DX: 404 when resource not provisioned, but 405 if canonical route. Plain
+    // text  or HTML response because missing ?_format query string.
     $response = $this->request('DELETE', $url, $request_options);
     if ($has_canonical_url) {
       $this->assertSame(405, $response->getStatusCode());
@@ -979,14 +982,15 @@ public function testDelete() {
       $this->assertSame(['text/html; charset=UTF-8'], $response->getHeader('Content-Type'));
     }
 
+
     $url->setOption('query', ['_format' => static::$format]);
 
 
-    // DX: 405 when resource not provisioned. 404 for non canonical.
+    // DX: 404 when resource not provisioned, 405 if canonical route.
     $response = $this->request('DELETE', $url, $request_options);
     if ($has_canonical_url) {
-      $this->assertSame(405, $response->getStatusCode());
       $this->assertSame(['GET, POST, HEAD'], $response->getHeader('Allow'));
+      $this->assertResourceErrorResponse(405, 'No route found for "DELETE ' . str_replace($this->baseUrl, '', $this->getUrl()->setAbsolute()->toString()) . '": Method Not Allowed (Allow: GET, POST, HEAD)', $response);
     }
     else {
       $this->assertResourceErrorResponse(404, 'No route found for "DELETE ' . str_replace($this->baseUrl, '', $this->getUrl()->setAbsolute()->toString()) . '"', $response);