diff --git a/src/TestSuite/EmailTrait.php b/src/TestSuite/EmailTrait.php
index d71f6ef4d6c..132ad07f728 100644
--- a/src/TestSuite/EmailTrait.php
+++ b/src/TestSuite/EmailTrait.php
@@ -26,14 +26,10 @@
  *
  * **tests/bootstrap.php**
  * ```
- * use Cake\Mailer\Email;
  * use Cake\TestSuite\TestEmailTransport;
  *
- * // replace with other transport configs if required
- * $config = Email::getConfigTransport('default');
- * $config['className'] = TestEmailTransport::class;
- * Email::dropTransport('default');
- * Email::setConfigTransport('default', $config);
+ * // replaces existing transports with the TestEmailTransport for email assertions
+ * TestEmailTransport::replaceAllTransports();
  * ```
  */
 trait EmailTrait
diff --git a/src/TestSuite/TestEmailTransport.php b/src/TestSuite/TestEmailTransport.php
index b00414e729c..0413aa4d2e0 100644
--- a/src/TestSuite/TestEmailTransport.php
+++ b/src/TestSuite/TestEmailTransport.php
@@ -41,6 +41,23 @@ public function send(Email $email)
         return true;
     }
 
+    /**
+     * Replaces all currently configured transports with this one
+     *
+     * @return void
+     */
+    public static function replaceAllTransports()
+    {
+        $configuredTransports = Email::configuredTransport();
+
+        foreach ($configuredTransports as $configuredTransport) {
+            $config = Email::getConfigTransport($configuredTransport);
+            $config['className'] = self::class;
+            Email::dropTransport($configuredTransport);
+            Email::setConfigTransport($configuredTransport, $config);
+        }
+    }
+
     /**
      * Gets emails sent
      *
diff --git a/tests/TestCase/TestSuite/TestEmailTransportTest.php b/tests/TestCase/TestSuite/TestEmailTransportTest.php
new file mode 100644
index 00000000000..e08a9387d46
--- /dev/null
+++ b/tests/TestCase/TestSuite/TestEmailTransportTest.php
@@ -0,0 +1,103 @@
+<?php
+/**
+ * CakePHP(tm) : Rapid Development Framework (https://cakephp.org)
+ * Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * For full copyright and license information, please see the LICENSE.txt
+ * Redistributions of files must retain the above copyright notice
+ *
+ * @copyright     Copyright (c) Cake Software Foundation, Inc. (https://cakefoundation.org)
+ * @link          https://cakephp.org CakePHP(tm) Project
+ * @since         3.7.0
+ * @license       https://opensource.org/licenses/mit-license.php MIT License
+ */
+namespace Cake\Test\TestCase\TestSuite;
+
+use Cake\Mailer\Email;
+use Cake\Network\Email\DebugTransport;
+use Cake\TestSuite\TestEmailTransport;
+use Cake\TestSuite\TestCase;
+
+class TestEmailTransportTest extends TestCase
+{
+    /**
+     * setUp
+     *
+     * @return void
+     */
+    public function setUp()
+    {
+        parent::setUp();
+
+        Email::drop('default');
+        Email::drop('alternate');
+        Email::dropTransport('transport_default');
+        Email::dropTransport('transport_alternate');
+
+        Email::setConfigTransport('transport_default', [
+            'className' => DebugTransport::class
+        ]);
+        Email::setConfigTransport('transport_alternate', [
+            'className' => DebugTransport::class
+        ]);
+
+        Email::setConfig('default', [
+            'transport' => 'transport_default',
+            'from' => 'default@example.com',
+        ]);
+        Email::setConfig('alternate', [
+            'transport' => 'transport_alternate',
+            'from' => 'alternate@example.com',
+        ]);
+    }
+
+    /**
+     * tearDown
+     *
+     * @return void
+     */
+    public function tearDown()
+    {
+        parent::tearDown();
+
+        Email::drop('default');
+        Email::drop('alternate');
+        Email::dropTransport('transport_default');
+        Email::dropTransport('transport_alternate');
+    }
+
+    /**
+     * tests replaceAllTransports
+     *
+     * @return void
+     */
+    public function testReplaceAllTransports()
+    {
+        TestEmailTransport::replaceAllTransports();
+
+        $config = Email::getConfigTransport('transport_default');
+        $this->assertSame(TestEmailTransport::class, $config['className']);
+
+        $config = Email::getConfigTransport('transport_alternate');
+        $this->assertSame(TestEmailTransport::class, $config['className']);
+    }
+
+    /**
+     * tests sending an email through the transport, getting it, and clearing all emails
+     *
+     * @return void
+     */
+    public function testSendGetAndClear()
+    {
+        TestEmailTransport::replaceAllTransports();
+
+        (new Email())
+            ->setTo('test@example.com')
+            ->send('test');
+        $this->assertCount(1, TestEmailTransport::getEmails());
+
+        TestEmailTransport::clearEmails();
+        $this->assertCount(0, TestEmailTransport::getEmails());
+    }
+}