Bug 35744: Implement +strings for GET /patrons/:patron_id

In order to retrieve the library's name and patron category's
description alongwith other patron's info.

Test plan:
Run the following command before and after this patch:

% curl -u koha:koha --request GET 'http://localhost:8081/api/v1/patrons/42' --header "Content-Type: application/json" --header "x-koha-embed: +strings" | jq

Notice that you now have _strings which contains the library's name and
patron category's description

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>

Koha/Patron.pm

@@ -2467,6 +2467,27 @@ sub to_api_mapping {
     };
 }
 
+=head3 strings_map
+
+Returns a map of column name to string representations including the string.
+
+=cut
+
+sub strings_map {
+    my ( $self, $params ) = @_;
+
+    return {
+        library_id => {
+            str  => $self->library->branchname,
+            type => 'library',
+        },
+        category_id => {
+            str  => $self->category->description,
+            type => 'patron_category',
+        }
+    };
+}
+
 =head3 queue_notice
 
     Koha::Patrons->queue_notice({ letter_params => $letter_params, message_name => 'DUE'});

api/v1/swagger/definitions/patron.yaml

@@ -378,6 +378,11 @@ properties:
     type:
       - boolean
     description: Protected status of the patron
+  _strings:
+    type:
+      - object
+      - "null"
+    description: A list of stringified coded values
 additionalProperties: false
 required:
   - surname

api/v1/swagger/paths/patrons.yaml

@@ -482,6 +482,7 @@
         items:
           type: string
           enum:
+            - +strings
             - extended_attributes
         collectionFormat: csv
     produces:

t/db_dependent/api/v1/patrons.t

@@ -230,7 +230,7 @@ subtest 'list() tests' => sub {
 
 subtest 'get() tests' => sub {
 
-    plan tests => 3;
+    plan tests => 4;
 
     $schema->storage->txn_begin;
     unauthorized_access_tests('GET', -1, undef);
@@ -315,6 +315,33 @@ subtest 'get() tests' => sub {
 
         $schema->storage->txn_rollback;
     };
+
+    subtest '+strings' => sub {
+
+        plan tests => 4;
+
+        $schema->storage->txn_begin;
+
+        my $patron = $builder->build_object( { class => 'Koha::Patrons' } );
+
+        my $librarian = $builder->build_object(
+            {
+                class => 'Koha::Patrons',
+                value => { flags => 2**4 }    # borrowers flag = 4
+            }
+        );
+        my $password = 'thePassword123';
+        $librarian->set_password( { password => $password, skip_validation => 1 } );
+        my $userid = $librarian->userid;
+
+        $t->get_ok( "//$userid:$password@/api/v1/patrons/" . $patron->id => { "x-koha-embed" => "+strings" } )
+            ->status_is(200)
+            ->json_has( '/_strings/library_id' => { str => $patron->library->branchname, type => 'library' } )
+            ->json_has(
+            '/_strings/category_id' => { str => $patron->category->description, type => 'patron_category' } );
+
+        $schema->storage->txn_rollback;
+    };
 };
 
 subtest 'add() tests' => sub {