diff --git a/mod/assign/lang/en/assign.php b/mod/assign/lang/en/assign.php
index 388f0efa21e..f42554e10cf 100644
--- a/mod/assign/lang/en/assign.php
+++ b/mod/assign/lang/en/assign.php
@@ -92,8 +92,7 @@ assignment submission for \'{$a->assignment}\'
 You can see it appended to your assignment submission:
 
     {$a->url}';
-$string['assignmentmailhtml'] = '<p>{$a->grader} has posted some feedback on your
-assignment submission for \'<i>{$a->assignment}</i>\'.</p>
+$string['assignmentmailhtml'] = '<p>{$a->grader} has posted some feedback on your assignment submission for \'<i>{$a->assignment}</i>\'.</p>
 <p>You can see it appended to your <a href="{$a->url}">assignment submission</a>.</p>';
 $string['assignmentmailsmall'] = '{$a->grader} has posted some feedback on your
 assignment submission for \'{$a->assignment}\' You can see it appended to your submission';
@@ -268,8 +267,7 @@ for \'{$a->assignment}\' at {$a->timeupdated}
 It is available here:
 
     {$a->url}';
-$string['gradersubmissionupdatedhtml'] = '{$a->username} has updated their assignment submission
-for <i>\'{$a->assignment}\'  at {$a->timeupdated}</i><br /><br />
+$string['gradersubmissionupdatedhtml'] = '{$a->username} has updated their assignment submission for <i>\'{$a->assignment}\'  at {$a->timeupdated}</i><br /><br />
 It is <a href="{$a->url}">available on the web site</a>.';
 $string['gradersubmissionupdatedsmall'] = '{$a->username} has updated their submission for assignment {$a->assignment}.';
 $string['gradeuser'] = 'Grade {$a}';
@@ -286,8 +284,7 @@ assignment submission for \'{$a->assignment}\'
 You can see it appended to your assignment submission:
 
     {$a->url}';
-$string['feedbackavailablehtml'] = '{$a->username} has posted some feedback on your
-assignment submission for \'<i>{$a->assignment}</i>\'<br /><br />
+$string['feedbackavailablehtml'] = '{$a->username} has posted some feedback on your assignment submission for \'<i>{$a->assignment}</i>\'<br /><br />
 You can see it appended to your <a href="{$a->url}">assignment submission</a>.';
 $string['feedbackavailablesmall'] = '{$a->username} has given feedback for assignment {$a->assignment}';
 $string['feedbackavailableanontext'] = 'You have new feedback on your
@@ -296,8 +293,7 @@ assignment submission for \'{$a->assignment}\'
 You can see it appended to your assignment submission:
 
     {$a->url}';
-$string['feedbackavailableanonhtml'] = 'You have new feedback on your
-assignment submission for \'<i>{$a->assignment}</i>\'<br /><br />
+$string['feedbackavailableanonhtml'] = 'You have new feedback on your assignment submission for \'<i>{$a->assignment}</i>\'<br /><br />
 You can see it appended to your <a href="{$a->url}">assignment submission</a>.';
 $string['feedbackavailableanonsmall'] = 'New feedback for assignment {$a->assignment}';
 $string['feedbackplugins'] = 'Feedback plugins';
@@ -580,8 +576,7 @@ $string['submissioncopiedtext'] = 'You have made a copy of your previous assignm
 You can see the status of your assignment submission:
 
     {$a->url}';
-$string['submissioncopiedhtml'] = '<p>You have made a copy of your previous
-assignment submission for \'<i>{$a->assignment}</i>\'.</p>
+$string['submissioncopiedhtml'] = '<p>You have made a copy of your previous assignment submission for \'<i>{$a->assignment}</i>\'.</p>
 <p>You can see the status of your <a href="{$a->url}">assignment submission</a>.</p>';
 $string['submissioncopiedsmall'] = 'You have copied your previous assignment submission for {$a->assignment}';
 $string['submissiondrafts'] = 'Require students to click the submit button';
@@ -603,8 +598,7 @@ $string['submissionreceiptothertext'] = 'Your assignment submission for \'{$a->a
 You can see the status of your assignment submission:
 
     {$a->url}';
-$string['submissionreceiptotherhtml'] = 'Your assignment submission for
-\'<i>{$a->assignment}</i>\' has been submitted.<br /><br />
+$string['submissionreceiptotherhtml'] = 'Your assignment submission for \'<i>{$a->assignment}</i>\' has been submitted.<br /><br />
 You can see the status of your <a href="{$a->url}">assignment submission</a>.';
 $string['submissionreceiptothersmall'] = 'Your assignment submission for {$a->assignment} has been submitted.';
 $string['submissionreceipts'] = 'Send submission receipts';
diff --git a/mod/assign/tests/generator.php b/mod/assign/tests/generator.php
index f4cbcef10a6..59ffc3b0321 100644
--- a/mod/assign/tests/generator.php
+++ b/mod/assign/tests/generator.php
@@ -41,7 +41,7 @@ trait mod_assign_test_generator {
      * Convenience function to create a testable instance of an assignment.
      *
      * @param array $params Array of parameters to pass to the generator
-     * @return testable_assign Testable wrapper around the assign class.
+     * @return mod_assign_testable_assign Testable wrapper around the assign class.
      */
     protected function create_instance($course, $params = [], $options = []) {
         $params['course'] = $course->id;
diff --git a/mod/assign/tests/locallib_test.php b/mod/assign/tests/locallib_test.php
index 5ca19a3933e..f6b4c5deae9 100644
--- a/mod/assign/tests/locallib_test.php
+++ b/mod/assign/tests/locallib_test.php
@@ -1765,8 +1765,41 @@ final class locallib_test extends \advanced_testcase {
         $messages = $sink->get_messages();
 
         $this->assertEquals(1, count($messages));
-        $this->assertEquals(1, $messages[0]->notification);
-        $this->assertEquals($assign->get_instance()->name, $messages[0]->contexturlname);
+
+        // Get some bits we will need to verify the content of the message.
+        $assignname = $assign->get_instance()->name;
+        $assignurl = (new \moodle_url('/mod/assign/view.php', ['id' => $assign->get_course_module()->id]))->out();
+        $teachername = fullname($teacher);
+        $assignsurl = (new \moodle_url('/mod/assign/index.php', ['id' => $course->id]))->out();
+        $courseurl = (new \moodle_url('/course/view.php', ['id' => $course->id]))->out();
+
+        $message = $messages[0];
+        $this->assertEquals(1, $message->notification);
+        $this->assertEquals($assign->get_instance()->name, $message->contexturlname);
+        $this->assertEquals("$teachername has given feedback for assignment $assignname", $message->subject, );
+        $this->assertEquals("$course->shortname -> Assignment -> $assignname
+---------------------------------------------------------------------
+$teachername has posted some feedback on your
+assignment submission for '$assignname'
+
+You can see it appended to your assignment submission:
+
+    $assignurl
+
+---------------------------------------------------------------------
+",
+            $message->fullmessage,
+        );
+        $this->assertEquals(
+            '<p><font face="sans-serif"><a href="' . $courseurl . '">' . $course->shortname . '</a> ' .
+            '-><a href="' . $assignsurl . '">Assignment</a> ' .
+            '-><a href="' . $assignurl . '">' . $assignname . '</a></font></p><hr />' .
+            '<font face="sans-serif"><p>' . $teachername . ' has posted some feedback on your ' .
+            'assignment submission for \'<i>' . $assignname . '</i>\'<br /><br />' . "\n" .
+            'You can see it appended to your <a href="' . $assignurl .
+            '">assignment submission</a>.</p></font><hr />',
+            $message->fullmessagehtml
+        );
     }
 
     public function test_cron_message_includes_courseid(): void {