diff --git a/auth/ldap/tests/plugin_test.php b/auth/ldap/tests/plugin_test.php
index 7f0855e0085..ebb6f31df25 100644
--- a/auth/ldap/tests/plugin_test.php
+++ b/auth/ldap/tests/plugin_test.php
@@ -386,8 +386,9 @@ class auth_ldap_plugin_testcase extends advanced_testcase {
         $auth = get_auth_plugin('ldap');
 
         $sink = $this->redirectEvents();
+        $mailsink = $this->redirectEmails();
         $auth->user_signup((object)$user, false);
-        $this->assertDebuggingCalled('Not sending email due to $CFG->noemailever config setting');
+        $this->assertEquals(1, $mailsink->count());
         $events = $sink->get_events();
         $sink->close();
 
diff --git a/badges/tests/badgeslib_test.php b/badges/tests/badgeslib_test.php
index aa074b47d8b..ce13ed8dcf4 100644
--- a/badges/tests/badgeslib_test.php
+++ b/badges/tests/badgeslib_test.php
@@ -41,8 +41,6 @@ class core_badges_badgeslib_testcase extends advanced_testcase {
         global $DB, $CFG;
         $this->resetAfterTest(true);
 
-        unset_config('noemailever');
-
         $CFG->enablecompletion = true;
 
         $user = $this->getDataGenerator()->create_user();
diff --git a/course/tests/courserequest_test.php b/course/tests/courserequest_test.php
index 3b85c334ae6..1e96d21e29c 100644
--- a/course/tests/courserequest_test.php
+++ b/course/tests/courserequest_test.php
@@ -81,8 +81,6 @@ class core_course_courserequest_testcase extends advanced_testcase {
         $this->resetAfterTest(true);
         $this->preventResetByRollback();
 
-        unset_config('noemailever');
-
         $defaultcategory = $DB->get_field_select('course_categories', "MIN(id)", "parent=0");
         set_config('enablecourserequests', 1);
         set_config('requestcategoryselection', 0);
@@ -138,8 +136,6 @@ class core_course_courserequest_testcase extends advanced_testcase {
         $this->resetAfterTest(true);
         $this->preventResetByRollback();
 
-        unset_config('noemailever');
-
         $this->setAdminUser();
         set_config('enablecourserequests', 1);
         set_config('requestcategoryselection', 0);
diff --git a/lib/phpunit/bootstrap.php b/lib/phpunit/bootstrap.php
index 4d573df0b00..add63122157 100644
--- a/lib/phpunit/bootstrap.php
+++ b/lib/phpunit/bootstrap.php
@@ -209,8 +209,6 @@ error_reporting($CFG->debug);
 ini_set('display_errors', '1');
 ini_set('log_errors', '1');
 
-$CFG->noemailever = true; // better not mail anybody from tests, override temporarily if necessary
-
 // some ugly hacks
 $CFG->themerev = 1;
 $CFG->jsrev = 1;
diff --git a/lib/phpunit/classes/util.php b/lib/phpunit/classes/util.php
index c5e408b3ae7..1c1928e0ff7 100644
--- a/lib/phpunit/classes/util.php
+++ b/lib/phpunit/classes/util.php
@@ -106,12 +106,15 @@ class phpunit_util extends testing_util {
         // Stop any message redirection.
         phpunit_util::stop_message_redirection();
 
-        // Stop any message redirection.
-        phpunit_util::stop_phpmailer_redirection();
-
         // Stop any message redirection.
         phpunit_util::stop_event_redirection();
 
+        // Start a new email redirection.
+        // This will clear any existing phpmailer redirection.
+        // We redirect all phpmailer output to this message sink which is
+        // called instead of phpmailer actually sending the message.
+        phpunit_util::start_phpmailer_redirection();
+
         // We used to call gc_collect_cycles here to ensure desctructors were called between tests.
         // This accounted for 25% of the total time running phpunit - so we removed it.
 
@@ -678,9 +681,11 @@ class phpunit_util extends testing_util {
      */
     public static function start_phpmailer_redirection() {
         if (self::$phpmailersink) {
-            self::stop_phpmailer_redirection();
+            // If an existing mailer sink is active, just clear it.
+            self::$phpmailersink->clear();
+        } else {
+            self::$phpmailersink = new phpunit_phpmailer_sink();
         }
-        self::$phpmailersink = new phpunit_phpmailer_sink();
         return self::$phpmailersink;
     }
 
diff --git a/lib/phpunit/tests/advanced_test.php b/lib/phpunit/tests/advanced_test.php
index 82c3b28a0af..1caf138c122 100644
--- a/lib/phpunit/tests/advanced_test.php
+++ b/lib/phpunit/tests/advanced_test.php
@@ -432,6 +432,8 @@ class core_phpunit_advanced_testcase extends advanced_testcase {
         $message2->notification      = 0;
 
         // There should be debugging message without redirection.
+        $mailsink = $this->redirectEmails();
+        $mailsink->close();
         message_send($message1);
         $this->assertDebuggingCalled(null, null, 'message_send() must print debug message that messaging is disabled in phpunit tests.');
 
diff --git a/lib/tests/messagelib_test.php b/lib/tests/messagelib_test.php
index 2d076bea8c6..9d86d0c8619 100644
--- a/lib/tests/messagelib_test.php
+++ b/lib/tests/messagelib_test.php
@@ -30,7 +30,6 @@ class core_messagelib_testcase extends advanced_testcase {
     public function test_message_provider_disabled() {
         $this->resetAfterTest();
         $this->preventResetByRollback();
-        unset_config('noemailever');
 
         // Disable instantmessage provider.
         $disableprovidersetting = 'moodle_instantmessage_disable';
@@ -382,8 +381,6 @@ class core_messagelib_testcase extends advanced_testcase {
         $this->preventResetByRollback();
         $this->resetAfterTest();
 
-        unset_config('noemailever');
-
         $user1 = $this->getDataGenerator()->create_user();
         $user2 = $this->getDataGenerator()->create_user();
 
@@ -717,7 +714,6 @@ class core_messagelib_testcase extends advanced_testcase {
 
         $this->resetAfterTest();
         $this->preventResetByRollback();
-        set_config('noemailever', 1);
 
         $user1 = $this->getDataGenerator()->create_user();
         $user2 = $this->getDataGenerator()->create_user();
@@ -734,24 +730,30 @@ class core_messagelib_testcase extends advanced_testcase {
         $message->smallmessage      = 'small message';
         $message->notification      = '0';
 
+        $mailsink = $this->redirectEmails();
+
+        // Sending outside of a transaction is fine.
         message_send($message);
-        $this->assertDebuggingCalled('Not sending email due to $CFG->noemailever config setting');
+        $this->assertEquals(1, $mailsink->count());
 
         $transaction1 = $DB->start_delegated_transaction();
 
+        $mailsink->clear();
         message_send($message);
-        $this->assertDebuggingNotCalled();
+        $this->assertEquals(0, $mailsink->count());
 
         $transaction2 = $DB->start_delegated_transaction();
 
+        $mailsink->clear();
         message_send($message);
-        $this->assertDebuggingNotCalled();
+        $this->assertEquals(0, $mailsink->count());
 
         try {
             $transaction2->rollback(new Exception('x'));
             $this->fail('Expecting exception');
         } catch (Exception $e) {}
         $this->assertDebuggingNotCalled();
+        $this->assertEquals(0, $mailsink->count());
 
         $this->assertTrue($DB->is_transaction_started());
 
@@ -760,11 +762,12 @@ class core_messagelib_testcase extends advanced_testcase {
             $this->fail('Expecting exception');
         } catch (Exception $e) {}
         $this->assertDebuggingNotCalled();
+        $this->assertEquals(0, $mailsink->count());
 
         $this->assertFalse($DB->is_transaction_started());
 
         message_send($message);
-        $this->assertDebuggingCalled('Not sending email due to $CFG->noemailever config setting');
+        $this->assertEquals(1, $mailsink->count());
     }
 
     public function test_forced_rollback() {
diff --git a/lib/tests/moodlelib_test.php b/lib/tests/moodlelib_test.php
index 004cc071ad5..206a6c9378f 100644
--- a/lib/tests/moodlelib_test.php
+++ b/lib/tests/moodlelib_test.php
@@ -2607,6 +2607,11 @@ class core_moodlelib_testcase extends advanced_testcase {
         $subject2 = 'subject 2';
         $messagetext2 = 'message text 2';
 
+        // Close the default email sink.
+        $sink = $this->redirectEmails();
+        $sink->close();
+
+        $CFG->noemailever = true;
         $this->assertNotEmpty($CFG->noemailever);
         email_to_user($user1, $user2, $subject, $messagetext);
         $this->assertDebuggingCalled('Not sending email due to $CFG->noemailever config setting');
@@ -2660,9 +2665,6 @@ class core_moodlelib_testcase extends advanced_testcase {
 
         $user = $this->getDataGenerator()->create_user();
 
-        // Set config to allow email_to_user() to be called.
-        $CFG->noemailever = false;
-
         // Update user password.
         $sink = $this->redirectEvents();
         $sink2 = $this->redirectEmails(); // Make sure we are redirecting emails.
diff --git a/lib/upgrade.txt b/lib/upgrade.txt
index 79e608d706b..7ea8021503a 100644
--- a/lib/upgrade.txt
+++ b/lib/upgrade.txt
@@ -4,6 +4,9 @@ information provided here is intended especially for developers.
 === 2.9 ===
 
 * \core\event\course_viewed 'other' argument renamed from coursesectionid to coursesectionnumber as it contains the section number.
+* PHPUnit: PHPMailer Sink is now started for all tests and is setup within the phpunit wrapper for advanced tests.
+  Catching debugging messages when sending mail will no longer work. Use $sink = $this->redirectEmails(); and then check
+  the message in the sink instead.
 
 === 2.8 ===
 
diff --git a/message/output/email/message_output_email.php b/message/output/email/message_output_email.php
index 247aa5fa028..1970606c09d 100644
--- a/message/output/email/message_output_email.php
+++ b/message/output/email/message_output_email.php
@@ -39,9 +39,6 @@ class message_output_email extends message_output {
     function send_message($eventdata) {
         global $CFG;
 
-        // Ignore $CFG->noemailever here because we want to test this code,
-        // the message sending fails later in email_to_user().
-
         // skip any messaging suspended and deleted users
         if ($eventdata->userto->auth === 'nologin' or $eventdata->userto->suspended or $eventdata->userto->deleted) {
             return true;
diff --git a/mod/forum/tests/mail_test.php b/mod/forum/tests/mail_test.php
index db6eb94cd64..2f6d81461c1 100644
--- a/mod/forum/tests/mail_test.php
+++ b/mod/forum/tests/mail_test.php
@@ -60,9 +60,6 @@ class mod_forum_mail_testcase extends advanced_testcase {
         // ensure that messages are sent out.
         $CFG->maxeditingtime = -1;
 
-        // Ensure that we don't prevent e-mail as this will cause unit test failures.
-        $CFG->noemailever = false;
-
         $this->helper = $helper;
     }
 
diff --git a/mod/forum/tests/maildigest_test.php b/mod/forum/tests/maildigest_test.php
index 19725bad229..d52eee4a951 100644
--- a/mod/forum/tests/maildigest_test.php
+++ b/mod/forum/tests/maildigest_test.php
@@ -72,9 +72,6 @@ class mod_forum_maildigest_testcase extends advanced_testcase {
         // messages are sent out.
         $CFG->maxeditingtime = 1;
 
-        // Ensure that we don't prevent e-mail as this will cause unit test failures.
-        $CFG->noemailever = false;
-
         // We must clear the subscription caches. This has to be done both before each test, and after in case of other
         // tests using these functions.
         \mod_forum\subscriptions::reset_forum_cache();