Add test, update docs

docs/source/endpoints/querystring.md

@@ -1,40 +1,36 @@
 ---
 myst:
   html_meta:
-    "description": "The @querystring endpoint returns the querystring configuration of plone.app.querystring."
-    "property=og:description": "The @querystring endpoint returns the querystring configuration of plone.app.querystring."
+    "description": "The @querystring endpoint returns metadata about available query operations."
+    "property=og:description": "The @querystring endpoint returns metadata about available query operations."
     "property=og:title": "Querystring"
     "keywords": "Plone, plone.restapi, REST, API, Querystring"
 ---
 
 # Querystring
 
-The `@querystring` endpoint returns the `querystring` configuration of `plone.app.querystring`.
+The `@querystring` endpoint returns metadata about the query operations that can be performed using the [`@querystringsearch`](querystringsearch) endpoint.
 
-Instead of simply exposing the `querystring` related `field` and `operation` entries from the registry, it serializes them in the same way that `p.a.querystring` does in its `@@querybuilderjsonconfig` view.
+The results include all of the indexes that can be queried, along with metadata about each index.
+The top-level `indexes` property includes all indexes, and the top-level `sortable_indexes` property includes only the indexes that can be used to sort.
 
-This form is structured in a more convenient way for frontends to process:
+Each index result includes a list of the query operations that can be performed on that index.
+The `operations` property contains the list of operations as dotted names.
+The `operators` property contains additional metadata about each operation.
 
-- *Vocabularies* will be resolved.
-  Their values will be inlined in the `values` property.
-- *Operations* will be inlined as well.
-  The `operations` property will contain the list of operations as dotted names.
-  The `operators` property will contain the full definition of each of those operations supported by that field.
-- Indexes that are flagged as *sortable* are listed in a dedicated top-level property `sortable_indexes`.
+If an index uses a vocabulary, the vocabulary values are included in the `values` property.
+The vocabulary is resolved in the same context where the `/@querystring` endpoint is called (requires `plone.app.querystring >= 2.1.0`).
 
-Available options for the querystring in a Plone site can be queried by interacting with the `/@querystring` endpoint on the portal root:
+## Get Querystring Config
 
-
-## Querystring Config
-
-To retrieve all `querystring` options in the portal, call the `/@querystring` endpoint with a `GET` request:
+To get the metadata about all query operations available in the portal, call the `/@querystring` endpoint with a `GET` request:
 
 ```{eval-rst}
 ..  http:example:: curl httpie python-requests
     :request: ../../../src/plone/restapi/tests/http-examples/querystring_get.req
 ```
 
-The server will respond with all `querystring` options in the portal:
+The server will respond with the metadata:
 
 ```{literalinclude} ../../../src/plone/restapi/tests/http-examples/querystring_get.resp
 :language: http

src/plone/restapi/tests/http-examples/querystring_get_contextual.req

@@ -0,0 +1,3 @@
+GET /plone/front-page/@querystring HTTP/1.1
+Accept: application/json
+Authorization: Basic YWRtaW46c2VjcmV0