diff --git a/public/mod/data/classes/courseformat/overview.php b/public/mod/data/classes/courseformat/overview.php
index c9a40e44191..c4db045b789 100644
--- a/public/mod/data/classes/courseformat/overview.php
+++ b/public/mod/data/classes/courseformat/overview.php
@@ -40,18 +40,28 @@ class overview extends \core_courseformat\activityoverviewbase {
     /** @var bool whether the user can see pendent entries or not. */
     private $canviewall;
 
+    /** @var array All the entries belonging to groups that the current user can view. */
+    private $allentries = [];
+
     /**
      * Constructor.
      *
      * @param cm_info $cm the course module instance.
+     * @param \core\output\renderer_helper $rendererhelper the renderer helper.
+     * @param \core_string_manager $stringmanager the string manager.
      */
     public function __construct(
-        cm_info $cm,
+            cm_info $cm,
+            /** @var \core\output\renderer_helper $rendererhelper the renderer helper */
+            protected readonly \core\output\renderer_helper $rendererhelper,
+            /** @var \core_string_manager $stringmanager the string manager */
+            protected readonly \core_string_manager $stringmanager,
     ) {
         parent::__construct($cm);
 
         $this->manager = manager::create_from_coursemodule($cm);
         $this->canviewall = has_capability('mod/data:approve', $cm->context);
+        $this->allentries = $this->manager->get_all_entries($this->get_groups_for_filtering());
     }
 
     #[\Override]
@@ -89,7 +99,7 @@ class overview extends \core_courseformat\activityoverviewbase {
         $toapprove = 0;
         if ($this->manager->get_approval_requested()) {
             // Let's calculate how many entries need to be approved.
-            $entries = $this->manager->filter_entries_by_approval($this->manager->get_all_entries(), 0);
+            $entries = $this->manager->filter_entries_by_approval($this->allentries, 0);
             $toapprove = count($entries);
             if ($toapprove > 0) {
                 $name = get_string('approve', 'data');
@@ -116,19 +126,11 @@ class overview extends \core_courseformat\activityoverviewbase {
 
     #[\Override]
     public function get_extra_overview_items(): array {
-        $columns = [];
-        // Add entry columns for each view.
-        if ($this->canviewall) {
-            $columns['totalentries'] = $this->get_extra_entries_overview();
-        } else {
-            $columns['totalentries'] = $this->get_extra_totalentries_overview();
-            $columns['myentries'] = $this->get_extra_myentries_overview();
-        }
-
-        // Add comments column for all views.
-        $columns['comments'] = $this->get_extra_comments_overview();
-
-        return $columns;
+        return [
+            'totalentries' => $this->get_extra_entries_overview(),
+            'myentries' => $this->get_extra_myentries_overview(),
+            'comments' => $this->get_extra_comments_overview(),
+        ];
     }
 
     /**
@@ -145,7 +147,7 @@ class overview extends \core_courseformat\activityoverviewbase {
 
         // Add total entries.
         return new overviewitem(
-            name: get_string('totalentries', 'data'),
+            name: $this->stringmanager->get_string('totalentries', 'data'),
             value: $totalentries,
             content: $totalentries,
             textalign: text_align::END,
@@ -155,12 +157,16 @@ class overview extends \core_courseformat\activityoverviewbase {
     /**
      * Get the "My entries" overview item.
      *
-     * @return overviewitem The overview item.
+     * @return ?overviewitem The overview item or null when the user is a student.
      */
-    private function get_extra_myentries_overview(): overviewitem {
+    private function get_extra_myentries_overview(): ?overviewitem {
         global $USER;
 
-        $myentries = $this->manager->filter_entries_by_user($this->manager->get_all_entries(), $USER->id);
+        if ($this->canviewall) {
+            return null;
+        }
+
+        $myentries = $this->manager->filter_entries_by_user($this->allentries, $USER->id);
         $totalmyentries = count($myentries);
 
         return new overviewitem(
@@ -177,12 +183,19 @@ class overview extends \core_courseformat\activityoverviewbase {
      * @return overviewitem The overview item.
      */
     private function get_extra_entries_overview(): overviewitem {
-        $allentries = $this->manager->get_all_entries();
-        $totalentries = count($allentries);
-
-        // Add total entries.
+        if ($this->canviewall) {
+            $name = get_string('entries', 'data');
+            $totalentries = count($this->allentries);
+        } else {
+            $allentries = $this->allentries;
+            if ($this->manager->get_approval_requested()) {
+                $allentries = $this->manager->filter_entries_by_approval($this->allentries, 1);
+            }
+            $name = get_string('totalentries', 'data');
+            $totalentries = count($allentries);
+        }
         return new overviewitem(
-            name: get_string('entries', 'data'),
+            name: $name,
             value: $totalentries,
             content: $totalentries,
             textalign: text_align::END,
@@ -208,7 +221,7 @@ class overview extends \core_courseformat\activityoverviewbase {
         }
 
         $approved = ($this->canviewall) ? null : 1;
-        $comments = $this->manager->get_comments(approved: $approved);
+        $comments = $this->manager->get_comments(approved: $approved, groups: $this->get_groups_for_filtering());
         $totalcomments = ($comments) ? count($comments) : 0;
         return new overviewitem(
             name: get_string('comments', 'data'),
diff --git a/public/mod/data/classes/manager.php b/public/mod/data/classes/manager.php
index fe5c05e9de4..c7f7262ea7f 100644
--- a/public/mod/data/classes/manager.php
+++ b/public/mod/data/classes/manager.php
@@ -69,16 +69,6 @@ class manager {
     /** @var cm_info course_modules record. */
     private $cm;
 
-    /** @var array the current data records.
-     * Do not access this attribute directly, use $this->get_all_entries instead
-     */
-    private $_entries = null;
-
-    /** @var array the current data comments.
-     * Do not access this attribute directly, use $this->get_all_comments instead
-     */
-    private $_comments = null;
-
     /** @var array the current data_fields records.
      * Do not access this attribute directly, use $this->get_field_records instead
      */
@@ -246,15 +236,20 @@ class manager {
     /**
      * Return the database entries.
      *
+     * @param array $groups to filter by.
      * @return [] the data records array.
      */
-    public function get_all_entries(): array {
+    public function get_all_entries(array $groups = []): array {
         global $DB;
 
-        if (empty($this->_entries)) {
-            $this->_entries = $DB->get_records('data_records', ['dataid' => $this->instance->id]);
+        if (empty($groups)) {
+            return $DB->get_records('data_records', ['dataid' => $this->instance->id]);
+        } else {
+            [$sql, $params] = $DB->get_in_or_equal(array_keys($groups), SQL_PARAMS_NAMED);
+            $sql = 'dataid = :id AND (groupid ' . $sql . ' OR groupid = 0)';
+            $params['id'] = $this->instance->id;
+            return $DB->get_records_select('data_records', $sql, $params);
         }
-        return $this->_entries;
     }
 
     /**
@@ -293,21 +288,18 @@ class manager {
      * Return the database comments filtered by approved entries.
      *
      * @param ?int $approved Approved value to filter by. Null for not filtering.
+     * @param ?array $groups to filter by.
      *
      * @return [] the filtered data comments array or null if there is no comment.
      */
-    public function get_comments(?int $approved = null): ?array {
+    public function get_comments(?int $approved = null, array $groups = []): ?array {
 
-        if ($this->_comments) {
-            return $this->_comments;
-        }
-
-        $entries = $this->get_all_entries();
+        $entries = $this->get_all_entries($groups);
         if (!is_null($approved)) {
             $entries = $this->filter_entries_by_approval($entries, $approved);
         }
 
-        $this->_comments = [];
+        $comments = [];
 
         // Initilising comment object.
         $args = new stdClass;
@@ -322,11 +314,11 @@ class manager {
             $comment = new \comment($args);
             $morecomments = $comment->get_comments();
             if ($morecomments) {
-                $this->_comments = array_merge($this->_comments, $morecomments);
+                $comments = array_merge($comments, $morecomments);
             }
         }
 
-        return $this->_comments;
+        return $comments;
     }
 
     /**
diff --git a/public/mod/data/tests/behat/overview_report.feature b/public/mod/data/tests/behat/overview_report.feature
index c67b0bf6e72..ef6c1cf7c34 100644
--- a/public/mod/data/tests/behat/overview_report.feature
+++ b/public/mod/data/tests/behat/overview_report.feature
@@ -13,9 +13,9 @@ Feature: Testing overview integration in database activity
       | fullname | shortname | category | enablecompletion |
       | Course 1 | C1        | 0        | 1                |
     And the following "course enrolments" exist:
-      | user | course | role           |
-      | teacher1 | C1 | editingteacher |
-      | student1 | C1 | student        |
+      | user     | course | role           |
+      | teacher1 | C1     | editingteacher |
+      | student1 | C1     | student        |
     And the following "activity" exists:
       | course          | C1                   |
       | activity        | data                 |
diff --git a/public/mod/data/tests/overview_test.php b/public/mod/data/tests/courseformat/overview_test.php
similarity index 79%
rename from public/mod/data/tests/overview_test.php
rename to public/mod/data/tests/courseformat/overview_test.php
index 0411319af98..0d72f988a5e 100644
--- a/public/mod/data/tests/overview_test.php
+++ b/public/mod/data/tests/courseformat/overview_test.php
@@ -14,9 +14,10 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
 
-namespace mod_data;
+namespace mod_data\courseformat;
 
 use core_courseformat\local\overview\overviewfactory;
+use mod_data\manager;
 
 /**
  * Tests for Database activity overview
@@ -135,8 +136,8 @@ final class overview_test extends \advanced_testcase {
                 'needsapproval' => true,
                 'entries' => [1, 1],
                 'expected' => [
-                        'link' => get_string('view', 'moodle'),
-                        'value' => 0,
+                    'link' => get_string('view', 'moodle'),
+                    'value' => 0,
                 ],
             ],
         ];
@@ -156,11 +157,11 @@ final class overview_test extends \advanced_testcase {
      * @return void
      */
     public function test_get_extra_entries_overview(
-            string $role,
-            bool $needsapproval,
-            array $entries,
-            array $myentries,
-            array $expected
+        string $role,
+        bool $needsapproval,
+        array $entries,
+        array $myentries,
+        array $expected
     ): void {
         $this->resetAfterTest();
 
@@ -206,13 +207,13 @@ final class overview_test extends \advanced_testcase {
         $items = overviewfactory::create($cm)->get_extra_overview_items();
 
         if (is_null($expected['totalentries'])) {
-            $this->assertArrayNotHasKey('totalentries', $items);
+            $this->assertNull($items['totalentries']);
         } else {
             $this->assertEquals($expected['totalentries'], $items['totalentries']->get_value());
         }
 
         if (is_null($expected['myentries'])) {
-            $this->assertArrayNotHasKey('myentries', $items);
+            $this->assertNull($items['myentries']);
         } else {
             $this->assertEquals($expected['myentries'], $items['myentries']->get_value());
         }
@@ -288,6 +289,96 @@ final class overview_test extends \advanced_testcase {
         ];
     }
 
+    /**
+     * Test get_extra_overview_items with groups.
+     *
+     * @covers ::get_extra_overview_items
+     */
+    public function test_get_extra_entries_overview_with_groups(): void {
+        $this->resetAfterTest();
+
+        $course = $this->getDataGenerator()->create_course();
+        $g1 = $this->getDataGenerator()->create_group(['courseid' => $course->id]);
+        $g2 = $this->getDataGenerator()->create_group(['courseid' => $course->id]);
+        $this->setAdminUser();
+
+        $activity = $this->getDataGenerator()->create_module(
+            manager::MODULE,
+            ['course' => $course, 'groupmode' => SEPARATEGROUPS],
+        );
+
+        // Add a field.
+        /** @var \mod_data_generator $generator */
+        $generator = $this->getDataGenerator()->get_plugin_generator('mod_data');
+        $fieldrecord = (object)[
+            'name' => 'myfield',
+            'type' => 'text',
+        ];
+        $field = $generator->create_field($fieldrecord, $activity);
+        $generator->create_entry(
+            $activity,
+            [$field->field->id => 'Example entry: All participants'],
+        );
+
+        // Create entries for each group.
+        $generator->create_entry(
+            $activity,
+            [$field->field->id => 'G1'],
+            $g1->id,
+        );
+        $generator->create_entry(
+            $activity,
+            [$field->field->id => 'G2'],
+            $g2->id,
+        );
+
+        $teacher = $this->getDataGenerator()->create_and_enrol($course, 'editingteacher');
+        $noneditingteacher = $this->getDataGenerator()->create_and_enrol($course, 'teacher');
+        groups_add_member($g1, $noneditingteacher->id);
+        $student = $this->getDataGenerator()->create_and_enrol($course, 'student');
+        groups_add_member($g1, $student->id);
+        $otherstudent = $this->getDataGenerator()->create_and_enrol($course, 'student');
+        groups_add_member($g2, $otherstudent->id);
+
+        $generator->create_entry(
+            $activity,
+            [$field->field->id => 'G1'],
+            $g1->id,
+            [],
+            null,
+            $student->id
+        );
+        $generator->create_entry(
+            $activity,
+            [$field->field->id => 'G2'],
+            $g2->id,
+            [],
+            null,
+            $otherstudent->id
+        );
+
+        // Editing teachers can see everything.
+        $this->setUser($teacher);
+        $cm = get_fast_modinfo($course)->get_cm($activity->cmid);
+        $items = overviewfactory::create($cm)->get_extra_overview_items();
+        $this->assertEquals(5, $items['totalentries']->get_value());
+        $this->assertNull($items['myentries']);
+
+        // Non-editing teachers can see their groups and all participants.
+        $this->setUser($noneditingteacher);
+        $cm = get_fast_modinfo($course)->get_cm($activity->cmid);
+        $items = overviewfactory::create($cm)->get_extra_overview_items();
+        $this->assertEquals(3, $items['totalentries']->get_value());
+        $this->assertNull($items['myentries']);
+
+        // Students can see their groups and all participants.
+        $this->setUser($student);
+        $cm = get_fast_modinfo($course)->get_cm($activity->cmid);
+        $items = overviewfactory::create($cm)->get_extra_overview_items();
+        $this->assertEquals(3, $items['totalentries']->get_value());
+        $this->assertEquals(1, $items['myentries']->get_value());
+    }
+
     /**
      * Test get_extra_comments_overview.
      *
@@ -301,10 +392,10 @@ final class overview_test extends \advanced_testcase {
      * @return void
      */
     public function test_get_extra_comments_overview(
-            string $role,
-            bool $needsapproval,
-            array $entries,
-            int $expected
+        string $role,
+        bool $needsapproval,
+        array $entries,
+        int $expected
     ): void {
         global $CFG;
 
diff --git a/public/mod/data/tests/manager_test.php b/public/mod/data/tests/manager_test.php
index 713d5b4f583..85c0623e7b7 100644
--- a/public/mod/data/tests/manager_test.php
+++ b/public/mod/data/tests/manager_test.php
@@ -786,17 +786,12 @@ final class manager_test extends \advanced_testcase {
         // Empty database should return empty array.
         $this->assertEmpty($manager->get_all_entries());
 
-        // Create data record.
-        $datarecords = new \stdClass();
-        $datarecords->userid = '2';
-        $datarecords->dataid = $data->id;
-
         // Add a field.
         /** @var \mod_data_generator $generator */
         $generator = $this->getDataGenerator()->get_plugin_generator('mod_data');
         $fieldrecord = (object)[
-                'name' => 'myfield',
-                'type' => 'text',
+            'name' => 'myfield',
+            'type' => 'text',
         ];
         $field = $generator->create_field($fieldrecord, $data);
         $generator->create_entry(
@@ -806,6 +801,53 @@ final class manager_test extends \advanced_testcase {
         $this->assertCount(1, $manager->get_all_entries());
     }
 
+    /**
+     * Test for get_all_entries() with groups parameter.
+     *
+     * @covers ::get_all_entries
+     */
+    public function test_get_all_entries_with_groups(): void {
+        $this->resetAfterTest();
+
+        $course = $this->getDataGenerator()->create_course();
+        $g1 = $this->getDataGenerator()->create_group(['courseid' => $course->id]);
+        $g2 = $this->getDataGenerator()->create_group(['courseid' => $course->id]);
+
+        $data = $this->getDataGenerator()->create_module(manager::MODULE, ['course' => $course, 'groupmode' => SEPARATEGROUPS]);
+        $manager = manager::create_from_instance($data);
+
+        // Add a field.
+        /** @var \mod_data_generator $generator */
+        $generator = $this->getDataGenerator()->get_plugin_generator('mod_data');
+        $fieldrecord = (object)[
+            'name' => 'myfield',
+            'type' => 'text',
+        ];
+        $field = $generator->create_field($fieldrecord, $data);
+        $generator->create_entry(
+            $data,
+            [$field->field->id => 'Example entry'],
+        );
+
+        // Create entries for each group.
+        $generator->create_entry(
+            $data,
+            [$field->field->id => 'G1'],
+            $g1->id,
+        );
+        $generator->create_entry(
+            $data,
+            [$field->field->id => 'G2'],
+            $g2->id,
+        );
+
+        $this->assertCount(3, $manager->get_all_entries([]));
+        $this->assertCount(2, $manager->get_all_entries([$g1->id => $g1]));
+        $this->assertCount(3, $manager->get_all_entries([$g1->id => $g1, $g2->id => $g2]));
+        // Non-existing group. It returns the entries with no group.
+        $this->assertCount(1, $manager->get_all_entries([666 => null]));
+    }
+
     /**
      * Test filter_entries_by_user.
      *
@@ -818,9 +860,9 @@ final class manager_test extends \advanced_testcase {
      * @return void
      */
     public function test_filter_entries_by_user(
-            array $entries,
-            array $myentries,
-            int $expected,
+        array $entries,
+        array $myentries,
+        int $expected,
     ): void {
         $this->resetAfterTest();
 
@@ -828,25 +870,25 @@ final class manager_test extends \advanced_testcase {
         $this->setAdminUser();
 
         $activity = $this->getDataGenerator()->create_module(
-                manager::MODULE,
-                ['course' => $course, 'approval' => 1],
+            manager::MODULE,
+            ['course' => $course, 'approval' => 1],
         );
 
         // Add a field.
         /** @var \mod_data_generator $generator */
         $generator = $this->getDataGenerator()->get_plugin_generator('mod_data');
         $fieldrecord = (object)[
-                'name' => 'myfield',
-                'type' => 'text',
+            'name' => 'myfield',
+            'type' => 'text',
         ];
         $field = $generator->create_field($fieldrecord, $activity);
         foreach ($entries as $entry => $approved) {
             $generator->create_entry(
-                    $activity,
-                    [$field->field->id => 'Example entry: '.$entry],
-                    0,
-                    [],
-                    ['approved' => $approved],
+                $activity,
+                [$field->field->id => 'Example entry: ' . $entry],
+                0,
+                [],
+                ['approved' => $approved],
             );
         }
 
@@ -854,11 +896,11 @@ final class manager_test extends \advanced_testcase {
         $this->setUser($currentuser);
         foreach ($myentries as $entry => $approved) {
             $generator->create_entry(
-                    $activity,
-                    [$field->field->id => 'Example entry: '.$entry],
-                    0,
-                    [],
-                    ['approved' => $approved],
+                $activity,
+                [$field->field->id => 'Example entry: ' . $entry],
+                0,
+                [],
+                ['approved' => $approved],
             );
         }
 
@@ -874,21 +916,21 @@ final class manager_test extends \advanced_testcase {
      */
     public static function provider_test_filter_entries_by_user(): array {
         return [
-                'Empty database filtered by current user' => [
-                        'entries' => [],
-                        'myentries' => [],
-                        'expected' => 0,
-                ],
-                'User without own entries filtered by current user' => [
-                        'entries' => [1, 0],
-                        'myentries' => [],
-                        'expected' => 0,
-                ],
-                'User with own entries filtered by current user' => [
-                        'entries' => [1, 0],
-                        'myentries' => [1, 0],
-                        'expected' => 2,
-                ],
+            'Empty database filtered by current user' => [
+                'entries' => [],
+                'myentries' => [],
+                'expected' => 0,
+            ],
+            'User without own entries filtered by current user' => [
+                'entries' => [1, 0],
+                'myentries' => [],
+                'expected' => 0,
+            ],
+            'User with own entries filtered by current user' => [
+                'entries' => [1, 0],
+                'myentries' => [1, 0],
+                'expected' => 2,
+            ],
         ];
     }
 
@@ -904,9 +946,9 @@ final class manager_test extends \advanced_testcase {
      * @return void
      */
     public function test_filter_entries_by_approval(
-            array $entries,
-            int $approvalfilter,
-            int $expected,
+        array $entries,
+        int $approvalfilter,
+        int $expected,
     ): void {
         $this->resetAfterTest();
 
@@ -914,25 +956,25 @@ final class manager_test extends \advanced_testcase {
         $this->setAdminUser();
 
         $activity = $this->getDataGenerator()->create_module(
-                manager::MODULE,
-                ['course' => $course, 'approval' => 1],
+            manager::MODULE,
+            ['course' => $course, 'approval' => 1],
         );
 
         // Add a field.
         /** @var \mod_data_generator $generator */
         $generator = $this->getDataGenerator()->get_plugin_generator('mod_data');
         $fieldrecord = (object)[
-                'name' => 'myfield',
-                'type' => 'text',
+            'name' => 'myfield',
+            'type' => 'text',
         ];
         $field = $generator->create_field($fieldrecord, $activity);
         foreach ($entries as $entry => $approved) {
             $generator->create_entry(
-                    $activity,
-                    [$field->field->id => 'Example entry: '.$entry],
-                    0,
-                    [],
-                    ['approved' => $approved],
+                $activity,
+                [$field->field->id => 'Example entry: ' . $entry],
+                0,
+                [],
+                ['approved' => $approved],
             );
         }
 
@@ -949,21 +991,21 @@ final class manager_test extends \advanced_testcase {
      */
     public static function provider_test_filter_entries_by_approval(): array {
         return [
-                'Empty database filtered by approved' => [
-                        'entries' => [],
-                        'approvalfilter' => 1,
-                        'expected' => 0,
-                ],
-                'Database with entries filtered by approved' => [
-                        'entries' => [1, 0, 1, 1],
-                        'approvalfilter' => 1,
-                        'expected' => 3,
-                ],
-                'Database with entries filtered by non approved' => [
-                        'entries' => [1, 0, 1, 1],
-                        'approvalfilter' => 0,
-                        'expected' => 1,
-                ],
+            'Empty database filtered by approved' => [
+                'entries' => [],
+                'approvalfilter' => 1,
+                'expected' => 0,
+            ],
+            'Database with entries filtered by approved' => [
+                'entries' => [1, 0, 1, 1],
+                'approvalfilter' => 1,
+                'expected' => 3,
+            ],
+            'Database with entries filtered by non approved' => [
+                'entries' => [1, 0, 1, 1],
+                'approvalfilter' => 0,
+                'expected' => 1,
+            ],
         ];
     }
 
@@ -1032,7 +1074,7 @@ final class manager_test extends \advanced_testcase {
     }
 
     /**
-     * Data provider for test comments extras.
+     * Data provider for test get_comments function.
      *
      * @return array
      */
@@ -1089,6 +1131,80 @@ final class manager_test extends \advanced_testcase {
         ];
     }
 
+    /**
+     * Test get_comments with groups parameter.
+     *
+     * @covers ::get_comments
+     */
+    public function test_get_comments_with_groups(): void {
+        global $CFG;
+
+        $this->resetAfterTest();
+        $this->setAdminUser();
+
+        $CFG->usecomments = true;
+
+        $course = $this->getDataGenerator()->create_course();
+        $g1 = $this->getDataGenerator()->create_group(['courseid' => $course->id]);
+        $g2 = $this->getDataGenerator()->create_group(['courseid' => $course->id]);
+
+        $data = $this->getDataGenerator()->create_module(
+            manager::MODULE,
+            ['course' => $course, 'approval' => 1, 'comments' => 1, 'groupmode' => SEPARATEGROUPS],
+        );
+
+        // Add a field.
+        /** @var \mod_data_generator $generator */
+        $generator = $this->getDataGenerator()->get_plugin_generator('mod_data');
+        $fieldrecord = (object)[
+            'name' => 'myfield',
+            'type' => 'text',
+        ];
+        $field = $generator->create_field($fieldrecord, $data);
+
+        $comments = [];
+        $comment = [
+            'contextlevel' => 'module',
+            'instanceid' => $data->cmid,
+            'component' => 'mod_data',
+            'content' => 'abc',
+            'area' => 'database_entry',
+        ];
+
+        $nogroupsentry = $generator->create_entry(
+            $data,
+            [$field->field->id => 'Example entry'],
+        );
+        $comment['itemid'] = $nogroupsentry;
+        $comments[] = $comment;
+
+        // Create entries for each group.
+        $g1entry = $generator->create_entry(
+            $data,
+            [$field->field->id => 'G1'],
+            $g1->id,
+        );
+        $comment['itemid'] = $g1entry;
+        $comments[] = $comment;
+
+        $g2entry = $generator->create_entry(
+            $data,
+            [$field->field->id => 'G2'],
+            $g2->id,
+        );
+        $comment['itemid'] = $g2entry;
+        $comments[] = $comment;
+
+        \core_comment_external::add_comments($comments);
+        $manager = manager::create_from_instance($data);
+
+        $this->assertCount(3, $manager->get_comments());
+        $this->assertCount(2, $manager->get_comments(groups: [$g1->id => $g1]));
+        $this->assertCount(3, $manager->get_comments(groups: [$g1->id => $g1, $g2->id => $g2]));
+        // Non-existing group. It returns the entries with no group.
+        $this->assertCount(1, $manager->get_comments(groups: [666 => null]));
+    }
+
     /**
      * Test get_approval_requested.
      *
@@ -1101,15 +1217,15 @@ final class manager_test extends \advanced_testcase {
         $this->setAdminUser();
 
         $activity = $this->getDataGenerator()->create_module(
-                manager::MODULE,
-                ['course' => $course, 'approval' => 1],
+            manager::MODULE,
+            ['course' => $course, 'approval' => 1],
         );
         $manager = manager::create_from_instance($activity);
         $this->assertEquals(1, $manager->get_approval_requested());
 
         $activity = $this->getDataGenerator()->create_module(
-                manager::MODULE,
-                ['course' => $course, 'approval' => 0],
+            manager::MODULE,
+            ['course' => $course, 'approval' => 0],
         );
         $manager = manager::create_from_instance($activity);
         $this->assertEquals(0, $manager->get_approval_requested());