Make RESTTestBase::httpRequest() work with HEAD requests

RESTTestBase::httpRequest() should work with HEAD requests so that one don't need to override it just to test custom REST services.

Are there usecases for that in core, like when testing the entity services?

There is a tiny bit of reference to HEAD requests in RequestBase and CSRFAccessCheck, and without this patch, that code is presumably untestable?

+++ b/core/modules/rest/src/Tests/RESTTestBase.php
@@ -92,6 +93,17 @@ protected function httpRequest($url, $method, $body = NULL, $mime_type = NULL) {
+        case 'HEAD':
+          $options = isset($body) ? array('absolute' => TRUE, 'query' => $body) : array('absolute' => TRUE);

hm, we are not doing that for GET requests, putting the $body on the URL as query parameters. So this should have at least a comment?

And this does not apply anymore.

#8: those references are no longer there.

Seams reasonable. On the longrun it would be nice to just use guzzle here. I think this would be simply more readable.

Absolutely. Issue for that already exists: #1841474: Convert REST tests to Guzzle (would also help with core moving from WTB to BTB).

.

Committed 13b4525 and pushed to 8.0.x, 8.1.x, 8.2.x (as this is a test-only change). Thanks!