Asserts that the most recently sent e-mail message has the given value.
The field in $name must have the content described in $value.
$name: Name of field or message property to assert. Examples: subject, body, id, ...
$value: Value of the field to assert.
$message: (optional) A message to display with the assertion. Do not translate messages: use format_string() to embed variables in the message text, not t(). If left blank, a default message will be displayed.
$group: (optional) The group this message is in, which is displayed in a column in test output. Use 'Debug' to indicate this is debugging output. Do not translate this string. Defaults to 'E-mail'; most tests do not override this default.
TRUE on pass, FALSE on fail.
protected function assertMail($name, $value = '', $message = '', $group = 'E-mail') {
$captured_emails = \Drupal::state()
->get('system.test_email_collector') ?: array();
$email = end($captured_emails);
return $this
->assertTrue($email && isset($email[$name]) && $email[$name] == $value, $message, $group);
}