From 3ea15bcef1f2deea0562be9024ce206d57babe09 Mon Sep 17 00:00:00 2001
From: Ilya Tregubov <ilya@moodle.com>
Date: Tue, 1 Aug 2023 11:38:00 +0800
Subject: [PATCH] MDL-43820 enrol_guest: Override find_instance

For guest enrol method there can be just one instance.
So we can just match by type
---
 enrol/guest/lib.php            | 22 +++++++++++++
 enrol/guest/tests/lib_test.php | 59 ++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+)
 create mode 100644 enrol/guest/tests/lib_test.php

diff --git a/enrol/guest/lib.php b/enrol/guest/lib.php
index 2e6ddf8f2b8..a9b7d9b6eb8 100644
--- a/enrol/guest/lib.php
+++ b/enrol/guest/lib.php
@@ -497,6 +497,28 @@ class enrol_guest_plugin extends enrol_plugin {
     public function is_csv_upload_supported(): bool {
         return true;
     }
+
+    /**
+     * Finds matching instances for a given course.
+     *
+     * @param array $enrolmentdata enrolment data.
+     * @param int $courseid Course ID.
+     * @return stdClass|null Matching instance
+     */
+    public function find_instance(array $enrolmentdata, int $courseid) : ?stdClass {
+
+        $instances = enrol_get_instances($courseid, false);
+        $instance = null;
+        foreach ($instances as $i) {
+            if ($i->enrol == 'guest') {
+                // There can be only one guest enrol instance so find first available.
+                $instance = $i;
+                break;
+            }
+        }
+        return $instance;
+    }
+
 }
 
 /**
diff --git a/enrol/guest/tests/lib_test.php b/enrol/guest/tests/lib_test.php
new file mode 100644
index 00000000000..1a35b5801b7
--- /dev/null
+++ b/enrol/guest/tests/lib_test.php
@@ -0,0 +1,59 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Guest enrolment tests.
+ *
+ * @package    enrol_guest
+ * @category   phpunit
+ * @copyright  2023 Ilya Tregubov <ilya.a.tregubov@gmail.com>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+namespace enrol_guest;
+
+class lib_test extends \advanced_testcase {
+
+    /**
+     * Test the behaviour of find_instance().
+     *
+     * @covers ::find_instance
+     */
+    public function test_find_instance() {
+        global $DB;
+        $this->resetAfterTest();
+
+        $cat = $this->getDataGenerator()->create_category();
+        // When we create a course, a guest enrolment instance is also created.
+        $course = $this->getDataGenerator()->create_course(['category' => $cat->id, 'shortname' => 'ANON']);
+
+        $guestplugin = enrol_get_plugin('guest');
+
+        $expected = $DB->get_record('enrol', ['courseid' => $course->id, 'enrol' => 'guest']);
+
+        // Let's try to add second instance - only 1 guest instance is possible.
+        $instanceid2 = null;
+        // Have to do this check since add_instance doesn't block adding second instance for guest plugin.
+        if ($guestplugin->can_add_instance($course->id)) {
+            $instanceid2 = $guestplugin->add_instance($course, []);
+        }
+        $this->assertNull($instanceid2);
+
+        $enrolmentdata = [];
+        $actual = $guestplugin->find_instance($enrolmentdata, $course->id);
+        $this->assertEquals($expected->id, $actual->id);
+    }
+
+}