diff --git a/completion/tests/coverage.php b/completion/tests/coverage.php
new file mode 100644
index 00000000000..2a758a79d66
--- /dev/null
+++ b/completion/tests/coverage.php
@@ -0,0 +1,47 @@
+<?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/>.
+
+defined('MOODLE_INTERNAL') || die();
+
+/**
+ * Coverage information for the core_completion.
+ *
+ * @package    core
+ * @category   phpunit
+ * @copyright  2022 Andrew Nicols <andrew@nicols.co.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+/**
+ * Coverage information for the core subsystem.
+ *
+ * @copyright  2018 Andrew Nicols <andrew@nicols.co.uk>
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+return new class extends phpunit_coverage_info {
+    /** @var array The list of folders relative to the plugin root to include in coverage generation. */
+    protected $includelistfolders = [
+        'criteria',
+    ];
+
+    /** @var array The list of files relative to the plugin root to include in coverage generation. */
+    protected $includelistfiles = [
+        'completion_aggregation.php',
+        'completion_completion.php',
+        'completion_criteria_completion.php',
+        'data_object.php'
+    ];
+};
diff --git a/lib/completionlib.php b/lib/completionlib.php
index 77c34bad9cf..94a9271327b 100644
--- a/lib/completionlib.php
+++ b/lib/completionlib.php
@@ -1024,6 +1024,20 @@ class completion_info {
             $userid = $USER->id;
         }
 
+        // Some call completion_info::get_data and pass $cm as an object with ID only. Make sure course is set as well.
+        if ($cm instanceof stdClass && !isset($cm->course)) {
+            $cm->course = $this->course_id;
+        }
+        // Make sure we're working on a cm_info object.
+        $cminfo = cm_info::create($cm, $userid);
+
+        // Create an anonymous function to remove the 'other_cm_completion_data_fetched' key.
+        $returnfilteredvalue = function(array $value): stdClass {
+            return (object) array_filter($value, function(string $key): bool {
+                return $key !== 'other_cm_completion_data_fetched';
+            }, ARRAY_FILTER_USE_KEY);
+        };
+
         // See if requested data is present in cache (use cache for current user only).
         $usecache = $userid == $USER->id;
         $cacheddata = array();
@@ -1036,19 +1050,22 @@ class completion_info {
                 if ($cacheddata['cacherev'] != $this->course->cacherev) {
                     // Course structure has been changed since the last caching, forget the cache.
                     $cacheddata = array();
-                } else if (isset($cacheddata[$cm->id])) {
-                    return (object)$cacheddata[$cm->id];
+                } else if (isset($cacheddata[$cminfo->id])) {
+                    $data = (array) $cacheddata[$cminfo->id];
+                    if (empty($data['other_cm_completion_data_fetched'])) {
+                        $data += $this->get_other_cm_completion_data($cminfo, $userid);
+                        $data['other_cm_completion_data_fetched'] = true;
+
+                        // Put in cache.
+                        $cacheddata[$cminfo->id] = $data;
+                        $completioncache->set($key, $cacheddata);
+                    }
+
+                    return $returnfilteredvalue($cacheddata[$cminfo->id]);
                 }
             }
         }
 
-        // Some call completion_info::get_data and pass $cm as an object with ID only. Make sure course is set as well.
-        if ($cm instanceof stdClass && !isset($cm->course)) {
-            $cm->course = $this->course_id;
-        }
-        // Make sure we're working on a cm_info object.
-        $cminfo = cm_info::create($cm, $userid);
-
         // Default data to return when no completion data is found.
         $defaultdata = [
             'id' => 0,
@@ -1086,12 +1103,9 @@ class completion_info {
                     $cacheddata[$data->cmid] = $defaultdata;
                     $cacheddata[$data->cmid]['coursemoduleid'] = $data->cmid;
                 } else {
-                    $cacheddata[$data->cmid] = (array) $data;
+                    unset($data->cmid);
+                    $cacheddata[$data->coursemoduleid] = (array) $data;
                 }
-
-                // Add the other completion data for this user in this module instance.
-                $othercminfo = $cminfos[$data->cmid];
-                $cacheddata[$othercminfo->id] += $this->get_other_cm_completion_data($othercminfo, $userid);
             }
 
             if (!isset($cacheddata[$cminfo->id])) {
@@ -1099,6 +1113,7 @@ class completion_info {
                 $this->internal_systemerror($errormessage);
             }
 
+            $data = $cacheddata[$cminfo->id];
         } else {
             // Get single record
             $data = $DB->get_record('course_modules_completion', array('coursemoduleid' => $cminfo->id, 'userid' => $userid));
@@ -1108,18 +1123,24 @@ class completion_info {
                 // Row not present counts as 'not complete'.
                 $data = $defaultdata;
             }
-            // Fill the other completion data for this user in this module instance.
-            $data += $this->get_other_cm_completion_data($cminfo, $userid);
 
-            // Put in cache
+            // Put in cache.
             $cacheddata[$cminfo->id] = $data;
         }
 
+        // Fill the other completion data for this user in this module instance.
+        $data += $this->get_other_cm_completion_data($cminfo, $userid);
+        $data['other_cm_completion_data_fetched'] = true;
+
+        // Put in cache
+        $cacheddata[$cminfo->id] = $data;
+
         if ($usecache) {
             $cacheddata['cacherev'] = $this->course->cacherev;
             $completioncache->set($key, $cacheddata);
         }
-        return (object)$cacheddata[$cminfo->id];
+
+        return $returnfilteredvalue($cacheddata[$cminfo->id]);
     }
 
     /**
@@ -1240,6 +1261,7 @@ class completion_info {
         $cmcontext = context_module::instance($data->coursemoduleid);
 
         $completioncache = cache::make('core', 'completion');
+        $cachekey = "{$data->userid}_{$cm->course}";
         if ($data->userid == $USER->id) {
             // Fetch other completion data to cache (e.g. require grade completion status, custom completion rule statues).
             $cminfo = cm_info::create($cm, $data->userid); // Make sure we're working on a cm_info object.
@@ -1249,18 +1271,19 @@ class completion_info {
             }
 
             // Update module completion in user's cache.
-            if (!($cachedata = $completioncache->get($data->userid . '_' . $cm->course))
+            if (!($cachedata = $completioncache->get($cachekey))
                     || $cachedata['cacherev'] != $this->course->cacherev) {
                 $cachedata = array('cacherev' => $this->course->cacherev);
             }
-            $cachedata[$cm->id] = $data;
-            $completioncache->set($data->userid . '_' . $cm->course, $cachedata);
+            $cachedata[$cm->id] = (array) $data;
+            $cachedata[$cm->id]['other_cm_completion_data_fetched'] = true;
+            $completioncache->set($cachekey, $cachedata);
 
             // reset modinfo for user (no need to call rebuild_course_cache())
             get_fast_modinfo($cm->course, 0, true);
         } else {
             // Remove another user's completion cache for this course.
-            $completioncache->delete($data->userid . '_' . $cm->course);
+            $completioncache->delete($cachekey);
         }
 
         // For single user actions the code must reevaluate some completion state instantly, see MDL-32103.
diff --git a/lib/tests/completionlib_test.php b/lib/tests/completionlib_test.php
index 00ae923f469..ecd75696b2f 100644
--- a/lib/tests/completionlib_test.php
+++ b/lib/tests/completionlib_test.php
@@ -29,7 +29,17 @@ defined('MOODLE_INTERNAL') || die();
 global $CFG;
 require_once($CFG->libdir.'/completionlib.php');
 
-class core_completionlib_testcase extends advanced_testcase {
+/**
+ * Completion tests.
+ *
+ * @package    core_completion
+ * @category   phpunit
+ * @copyright  2008 Sam Marshall
+ * @copyright  2013 Frédéric Massart
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @coversDefaultClass \completion_info
+ */
+class completionlib_test extends advanced_testcase {
     protected $course;
     protected $user;
     protected $module1;
@@ -79,6 +89,10 @@ class core_completionlib_testcase extends advanced_testcase {
     public static function assertEquals($expected, $actual, string $message = '', float $delta = 0, int $maxDepth = 10,
                                         bool $canonicalize = false, bool $ignoreCase = false): void {
         // Nasty cheating hack: prevent random failures on timemodified field.
+        if (is_array($actual) && (is_object($expected) || is_array($expected))) {
+            $actual = (object) $actual;
+            $expected = (object) $expected;
+        }
         if (is_object($expected) and is_object($actual)) {
             if (property_exists($expected, 'timemodified') and property_exists($actual, 'timemodified')) {
                 if ($expected->timemodified + 1 == $actual->timemodified) {
@@ -90,6 +104,10 @@ class core_completionlib_testcase extends advanced_testcase {
         parent::assertEquals($expected, $actual, $message, $delta, $maxDepth, $canonicalize, $ignoreCase);
     }
 
+    /**
+     * @covers ::is_enabled_for_site
+     * @covers ::is_enabled
+     */
     public function test_is_enabled() {
         global $CFG;
         $this->mock_setup();
@@ -125,6 +143,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $this->assertEquals(COMPLETION_TRACKING_AUTOMATIC, $c->is_enabled($cm));
     }
 
+    /**
+     * @covers ::update_state
+     */
     public function test_update_state() {
         $this->mock_setup();
 
@@ -348,6 +369,7 @@ class core_completionlib_testcase extends advanced_testcase {
      * @param int $completionusegrade
      * @param string $unsetfield
      * @param int $expectedstate
+     * @covers ::internal_get_state
      */
     public function test_internal_get_state(int $completionview, int $completionusegrade, string $unsetfield, int $expectedstate) {
         $this->setup_data();
@@ -379,6 +401,7 @@ class core_completionlib_testcase extends advanced_testcase {
      * Provider for the test_internal_get_state_with_grade_criteria.
      *
      * @return array
+     * @covers ::internal_get_state
      */
     public function test_internal_get_state_with_grade_criteria_provider() {
         return [
@@ -432,6 +455,7 @@ class core_completionlib_testcase extends advanced_testcase {
      * @param array $completioncriteria The completion criteria to use
      * @param int|null $studentgrade Grade to assign to student
      * @param int $expectedstate Expected completion state
+     * @covers ::internal_get_state
      */
     public function test_internal_get_state_with_grade_criteria(array $completioncriteria, ?int $studentgrade, int $expectedstate) {
         $this->setup_data();
@@ -472,6 +496,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Covers the case where internal_get_state() is being called for a user different from the logged in user.
+     *
+     * @covers ::internal_get_state
      */
     public function test_internal_get_state_with_different_user() {
         $this->setup_data();
@@ -514,6 +540,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test for internal_get_state() for an activity that supports custom completion.
+     *
+     * @covers ::internal_get_state
      */
     public function test_internal_get_state_with_custom_completion() {
         $this->setup_data();
@@ -540,6 +568,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $this->assertEquals(COMPLETION_COMPLETE, $completion);
     }
 
+    /**
+     * @covers ::set_module_viewed
+     */
     public function test_set_module_viewed() {
         $this->mock_setup();
 
@@ -595,6 +626,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $c->set_module_viewed($cm, 1337);
     }
 
+    /**
+     * @covers ::count_user_data
+     */
     public function test_count_user_data() {
         global $DB;
         $this->mock_setup();
@@ -611,6 +645,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $this->assertEquals(666, $c->count_user_data($cm));
     }
 
+    /**
+     * @covers ::delete_all_state
+     */
     public function test_delete_all_state() {
         global $DB;
         $this->mock_setup();
@@ -628,6 +665,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $c->delete_all_state($cm);
     }
 
+    /**
+     * @covers ::reset_all_state
+     */
     public function test_reset_all_state() {
         global $DB;
         $this->mock_setup();
@@ -703,6 +743,7 @@ class core_completionlib_testcase extends advanced_testcase {
      * @param bool $sameuser Whether the user calling get_data() is the user itself.
      * @param bool $hasrecord Whether to create a course_modules_completion record.
      * @param int $completion The completion state expected.
+     * @covers ::get_data
      */
     public function test_get_data(bool $wholecourse, bool $sameuser, bool $hasrecord, int $completion) {
         global $DB;
@@ -760,26 +801,6 @@ class core_completionlib_testcase extends advanced_testcase {
             $this->assertEquals(0, $result->id);
         }
 
-        // Check caching.
-        $key = "{$user->id}_{$this->course->id}";
-        $cache = cache::make('core', 'completion');
-        if ($iscached) {
-            // If we expect this to be cached, then fetching the result must match the cached data.
-            $this->assertEquals($result, (object)$cache->get($key)[$cm->id]);
-
-            // Check cached data for other course modules in the course.
-            // The sample module created in setup_data() should suffice to confirm this.
-            $othercm = get_coursemodule_from_instance('forum', $this->module1->id);
-            if ($wholecourse) {
-                $this->assertArrayHasKey($othercm->id, $cache->get($key));
-            } else {
-                $this->assertArrayNotHasKey($othercm->id, $cache->get($key));
-            }
-        } else {
-            // Otherwise, this should not be cached.
-            $this->assertFalse($cache->get($key));
-        }
-
         // Check that we are including relevant completion data for the module.
         if (!$wholecourse) {
             $this->assertTrue(property_exists($result, 'viewed'));
@@ -787,8 +808,74 @@ class core_completionlib_testcase extends advanced_testcase {
         }
     }
 
+    /**
+     * @covers ::get_data
+     */
+    public function test_get_data_successive_calls(): void {
+        global $DB;
+
+        $this->setup_data();
+        $this->setUser($this->user);
+
+        $choicegenerator = $this->getDataGenerator()->get_plugin_generator('mod_choice');
+        $choice = $choicegenerator->create_instance([
+            'course' => $this->course->id,
+            'completion' => COMPLETION_TRACKING_AUTOMATIC,
+            'completionview' => true,
+            'completionsubmit' => true,
+        ]);
+
+        $cm = get_coursemodule_from_instance('choice', $choice->id);
+
+        // Let's manually create a course completion record instead of going through the hoops to complete an activity.
+        $cmcompletionrecord = (object) [
+            'coursemoduleid' => $cm->id,
+            'userid' => $this->user->id,
+            'completionstate' => COMPLETION_NOT_VIEWED,
+            'viewed' => 0,
+            'overrideby' => null,
+            'timemodified' => 0,
+        ];
+        $DB->insert_record('course_modules_completion', $cmcompletionrecord);
+
+        // Mock other completion data.
+        $completioninfo = new completion_info($this->course);
+
+        $modinfo = get_fast_modinfo($this->course);
+        $results = [];
+        foreach ($modinfo->cms as $testcm) {
+            $result = $completioninfo->get_data($testcm, true);
+            $this->assertTrue(property_exists($result, 'id'));
+            $this->assertTrue(property_exists($result, 'coursemoduleid'));
+            $this->assertTrue(property_exists($result, 'userid'));
+            $this->assertTrue(property_exists($result, 'completionstate'));
+            $this->assertTrue(property_exists($result, 'viewed'));
+            $this->assertTrue(property_exists($result, 'overrideby'));
+            $this->assertTrue(property_exists($result, 'timemodified'));
+            $this->assertFalse(property_exists($result, 'other_cm_completion_data_fetched'));
+
+            $this->assertEquals($testcm->id, $result->coursemoduleid);
+            $this->assertEquals($this->user->id, $result->userid);
+            $this->assertEquals(0, $result->viewed);
+
+            $results[$testcm->id] = $result;
+        }
+
+        $result = $completioninfo->get_data($cm);
+        $this->assertTrue(property_exists($result, 'customcompletion'));
+
+        // The data should match when fetching modules individually.
+        (cache::make('core', 'completion'))->purge();
+        foreach ($modinfo->cms as $testcm) {
+            $result = $completioninfo->get_data($testcm, false);
+            $this->assertEquals($result, $results[$testcm->id]);
+        }
+    }
+
     /**
      * Tests for completion_info::get_other_cm_completion_data().
+     *
+     * @covers ::get_other_cm_completion_data
      */
     public function test_get_other_cm_completion_data() {
         global $DB;
@@ -862,6 +949,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $this->assertEmpty($choice2completiondata);
     }
 
+    /**
+     * @covers ::internal_set_data
+     */
     public function test_internal_set_data() {
         global $DB;
         $this->setup_data();
@@ -887,8 +977,15 @@ class core_completionlib_testcase extends advanced_testcase {
         $this->assertEquals($d1, $data->id);
         $cache = cache::make('core', 'completion');
         // Cache was not set for another user.
-        $this->assertEquals(array('cacherev' => $this->course->cacherev, $cm->id => $data),
-            $cache->get($data->userid . '_' . $cm->course));
+        $cachevalue = $cache->get("{$data->userid}_{$cm->course}");
+        $this->assertEquals([
+            'cacherev' => $this->course->cacherev,
+            $cm->id => array_merge(
+                (array) $data,
+                ['other_cm_completion_data_fetched' => true]
+            ),
+        ],
+        $cachevalue);
 
         // 2) Test with existing data and for different user.
         $forum2 = $this->getDataGenerator()->create_module('forum', array('course' => $this->course->id), $completionauto);
@@ -906,7 +1003,11 @@ class core_completionlib_testcase extends advanced_testcase {
         $c->internal_set_data($cm2, $d2);
         // Cache for current user returns the data.
         $cachevalue = $cache->get($data->userid . '_' . $cm->course);
-        $this->assertEquals($data, $cachevalue[$cm->id]);
+        $this->assertEquals(array_merge(
+            (array) $data,
+            ['other_cm_completion_data_fetched' => true]
+        ), $cachevalue[$cm->id]);
+
         // Cache for another user is not filled.
         $this->assertEquals(false, $cache->get($d2->userid . '_' . $cm2->course));
 
@@ -958,6 +1059,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $this->assertEquals($this->user->id, reset($actual)->userid);
     }
 
+    /**
+     * @covers ::get_progress_all
+     */
     public function test_get_progress_all_few() {
         global $DB;
         $this->mock_setup();
@@ -992,6 +1096,9 @@ class core_completionlib_testcase extends advanced_testcase {
             ), $c->get_progress_all(false));
     }
 
+    /**
+     * @covers ::get_progress_all
+     */
     public function test_get_progress_all_lots() {
         global $DB;
         $this->mock_setup();
@@ -1047,6 +1154,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $this->assertCount(count($tracked), $result);
     }
 
+    /**
+     * @covers ::inform_grade_changed
+     */
     public function test_inform_grade_changed() {
         $this->mock_setup();
 
@@ -1115,6 +1225,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $c->inform_grade_changed($cm, $item, $grade, true);
     }
 
+    /**
+     * @covers ::internal_get_grade_state
+     */
     public function test_internal_get_grade_state() {
         $this->mock_setup();
 
@@ -1157,6 +1270,9 @@ class core_completionlib_testcase extends advanced_testcase {
             completion_info::internal_get_grade_state($item, $grade));
     }
 
+    /**
+     * @test ::get_activities
+     */
     public function test_get_activities() {
         global $CFG;
         $this->resetAfterTest();
@@ -1198,6 +1314,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $this->assertFalse(isset($activities[$data2->cmid]));
     }
 
+    /**
+     * @test ::has_activities
+     */
     public function test_has_activities() {
         global $CFG;
         $this->resetAfterTest();
@@ -1223,7 +1342,8 @@ class core_completionlib_testcase extends advanced_testcase {
     /**
      * Test that data is cleaned up when we delete courses that are set as completion criteria for other courses
      *
-     * @return void
+     * @covers ::delete_course_completion_data
+     * @covers ::delete_all_completion_data
      */
     public function test_course_delete_prerequisite() {
         global $DB;
@@ -1260,6 +1380,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test course module completion update event.
+     *
+     * @covers \core\event\course_module_completion_updated
      */
     public function test_course_module_completion_updated_event() {
         global $USER, $CFG;
@@ -1297,6 +1419,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test course completed event.
+     *
+     * @covers \core\event\course_completed
      */
     public function test_course_completed_event() {
         global $USER;
@@ -1326,6 +1450,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test course completed message.
+     *
+     * @covers \core\event\course_completed
      */
     public function test_course_completed_message() {
         $this->setup_data();
@@ -1352,6 +1478,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test course completed event.
+     *
+     * @covers \core\event\course_completion_updated
      */
     public function test_course_completion_updated_event() {
         $this->setup_data();
@@ -1378,6 +1506,9 @@ class core_completionlib_testcase extends advanced_testcase {
         $this->assertEventLegacyLogData($expectedlegacylog, $event);
     }
 
+    /**
+     * @covers \completion_can_view_data
+     */
     public function test_completion_can_view_data() {
         $this->setup_data();
 
@@ -1413,6 +1544,7 @@ class core_completionlib_testcase extends advanced_testcase {
      * @param int|null $passinggrade Passing grade to set for the test activity.
      * @param string|null $expectedexception Expected exception.
      * @param int|null $expectedresult The expected completion status.
+     * @covers ::get_grade_completion
      */
     public function test_get_grade_completion(bool $completionusegrade, bool $hasgrade, ?int $passinggrade,
         ?string $expectedexception, ?int $expectedresult) {
@@ -1445,6 +1577,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test the return value for cases when the activity module does not have associated grade_item.
+     *
+     * @covers ::get_grade_completion
      */
     public function test_get_grade_completion_without_grade_item() {
         global $DB;
@@ -1483,6 +1617,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test for aggregate_completions().
+     *
+     * @covers \aggregate_completions
      */
     public function test_aggregate_completions() {
         global $DB;
@@ -1577,6 +1713,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test for completion_completion::_save().
+     *
+     * @covers \completion_completion::_save
      */
     public function test_save() {
         global $DB;
@@ -1621,6 +1759,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test for completion_completion::mark_enrolled().
+     *
+     * @covers \completion_completion::mark_enrolled
      */
     public function test_mark_enrolled() {
         global $DB;
@@ -1662,6 +1802,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test for completion_completion::mark_inprogress().
+     *
+     * @covers \completion_completion::mark_inprogress
      */
     public function test_mark_inprogress() {
         global $DB;
@@ -1703,6 +1845,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test for completion_completion::mark_complete().
+     *
+     * @covers \completion_completion::mark_complete
      */
     public function test_mark_complete() {
         global $DB;
@@ -1743,6 +1887,8 @@ class core_completionlib_testcase extends advanced_testcase {
 
     /**
      * Test for completion_criteria_completion::mark_complete().
+     *
+     * @covers \completion_criteria_completion::mark_complete
      */
     public function test_criteria_mark_complete() {
         global $DB;