Use voluptuous for smtp (#3048)

Make note of the breaking change in release notes

homeassistant/components/notify/smtp.py

@@ -10,31 +10,46 @@ from email.mime.multipart import MIMEMultipart
 from email.mime.text import MIMEText
 from email.mime.image import MIMEImage
 
+import voluptuous as vol
+
+import homeassistant.helpers.config_validation as cv
 from homeassistant.components.notify import (
-    ATTR_TITLE, ATTR_DATA, DOMAIN, BaseNotificationService)
-from homeassistant.helpers import validate_config
+    ATTR_TITLE, ATTR_DATA, PLATFORM_SCHEMA, BaseNotificationService)
+from homeassistant.const import (CONF_USERNAME, CONF_PASSWORD, CONF_PORT)
 
 _LOGGER = logging.getLogger(__name__)
 
 ATTR_IMAGES = 'images'  # optional embedded image file attachments
 
+CONF_STARTTLS = 'starttls'
+CONF_SENDER = 'sender'
+CONF_RECIPIENT = 'recipient'
+CONF_DEBUG = 'debug'
+CONF_SERVER = 'server'
+
+PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
+    vol.Required(CONF_RECIPIENT): cv.string,
+    vol.Optional(CONF_SERVER, default='localhost'): cv.string,
+    vol.Optional(CONF_PORT, default=25): cv.port,
+    vol.Optional(CONF_SENDER): cv.string,
+    vol.Optional(CONF_STARTTLS, default=False): cv.boolean,
+    vol.Optional(CONF_USERNAME): cv.string,
+    vol.Optional(CONF_PASSWORD): cv.string,
+    vol.Optional(CONF_DEBUG, default=False): cv.boolean,
+})
+
 
 def get_service(hass, config):
     """Get the mail notification service."""
-    if not validate_config({DOMAIN: config},
-                           {DOMAIN: ['recipient']},
-                           _LOGGER):
-        return None
-
     mail_service = MailNotificationService(
-        config.get('server', 'localhost'),
-        int(config.get('port', '25')),
-        config.get('sender', None),
-        int(config.get('starttls', 0)),
-        config.get('username', None),
-        config.get('password', None),
-        config.get('recipient', None),
-        config.get('debug', 0))
+        config.get(CONF_SERVER),
+        config.get(CONF_PORT),
+        config.get(CONF_SENDER),
+        config.get(CONF_STARTTLS),
+        config.get(CONF_USERNAME),
+        config.get(CONF_PASSWORD),
+        config.get(CONF_RECIPIENT),
+        config.get(CONF_DEBUG))
 
     if mail_service.connection_is_valid():
         return mail_service
@@ -65,7 +80,7 @@ class MailNotificationService(BaseNotificationService):
         mail = smtplib.SMTP(self._server, self._port, timeout=5)
         mail.set_debuglevel(self.debug)
         mail.ehlo_or_helo_if_needed()
-        if self.starttls == 1:
+        if self.starttls:
             mail.starttls()
             mail.ehlo()
         if self.username and self.password: