setSenderMail example

$this->assertEquals('', $message->getSenderName());
    $this->assertEquals('', $message->getSenderMail());
    $this->assertFalse($message->copySender());

    // Check for default values.     $this->assertEquals('feedback', $message->getContactForm()->id());
    $this->assertFalse($message->isPersonal());

    // Set some values and check for them afterwards.     $message->setMessage('welcome_message');
    $message->setSenderName('sender_name');
    $message->setSenderMail('sender_mail');
    $message->setCopySender(TRUE);

    $this->assertEquals('welcome_message', $message->getMessage());
    $this->assertEquals('sender_name', $message->getSenderName());
    $this->assertEquals('sender_mail', $message->getSenderMail());
    $this->assertTrue($message->copySender());

    $no_access_user = $this->createUser([], NULL, FALSE, ['uid' => 2]);
    $access_user = $this->createUser(['access site-wide contact form'], NULL, FALSE, ['uid' => 3]);
    $admin = $this->createUser(['administer contact forms'], NULL, FALSE, ['uid' => 4]);