fixes #11848 (#11915)

Adding tests to check the component after latest patch

.coveragerc

@@ -341,7 +341,6 @@ omit =
     homeassistant/components/cover/scsgate.py
     homeassistant/components/device_tracker/actiontec.py
     homeassistant/components/device_tracker/aruba.py
-    homeassistant/components/device_tracker/asuswrt.py
     homeassistant/components/device_tracker/automatic.py
     homeassistant/components/device_tracker/bbox.py
     homeassistant/components/device_tracker/bluetooth_le_tracker.py

homeassistant/components/device_tracker/asuswrt.py

@@ -25,9 +25,7 @@
 
 CONF_PUB_KEY = 'pub_key'
 CONF_SSH_KEY = 'ssh_key'
-
 DEFAULT_SSH_PORT = 22
-
 SECRET_GROUP = 'Password or SSH Key'
 
 PLATFORM_SCHEMA = vol.All(
@@ -118,20 +116,10 @@ def __init__(self, config):
         self.port = config[CONF_PORT]
 
         if self.protocol == 'ssh':
-            if not (self.ssh_key or self.password):
-                _LOGGER.error("No password or private key specified")
-                self.success_init = False
-                return
-
             self.connection = SshConnection(
                 self.host, self.port, self.username, self.password,
                 self.ssh_key, self.mode == 'ap')
         else:
-            if not self.password:
-                _LOGGER.error("No password specified")
-                self.success_init = False
-                return
-
             self.connection = TelnetConnection(
                 self.host, self.port, self.username, self.password,
                 self.mode == 'ap')
@@ -177,11 +165,16 @@ def get_asuswrt_data(self):
         """
         devices = {}
         devices.update(self._get_wl())
-        devices = self._get_arp(devices)
-        devices = self._get_neigh(devices)
+        devices.update(self._get_arp())
+        devices.update(self._get_neigh(devices))
         if not self.mode == 'ap':
             devices.update(self._get_leases(devices))
-        return devices
+
+        ret_devices = {}
+        for key in devices:
+            if devices[key].ip is not None:
+                ret_devices[key] = devices[key]
+        return ret_devices
 
     def _get_wl(self):
         lines = self.connection.run_command(_WL_CMD)
@@ -219,18 +212,13 @@ def _get_neigh(self, cur_devices):
         result = _parse_lines(lines, _IP_NEIGH_REGEX)
         devices = {}
         for device in result:
-            if device['mac']:
+            if device['mac'] is not None:
                 mac = device['mac'].upper()
-                devices[mac] = Device(mac, None, None)
-            else:
-                cur_devices = {
-                    k: v for k, v in
-                    cur_devices.items() if v.ip != device['ip']
-                }
-        cur_devices.update(devices)
-        return cur_devices
-
-    def _get_arp(self, cur_devices):
+                old_ip = cur_devices.get(mac, {}).ip or None
+                devices[mac] = Device(mac, device.get('ip', old_ip), None)
+        return devices
+
+    def _get_arp(self):
         lines = self.connection.run_command(_ARP_CMD)
         if not lines:
             return {}
@@ -240,13 +228,7 @@ def _get_arp(self, cur_devices):
             if device['mac']:
                 mac = device['mac'].upper()
                 devices[mac] = Device(mac, device['ip'], None)
-            else:
-                cur_devices = {
-                    k: v for k, v in
-                    cur_devices.items() if v.ip != device['ip']
-                }
-        cur_devices.update(devices)
-        return cur_devices
+        return devices
 
 
 class _Connection:
@@ -272,7 +254,7 @@ class SshConnection(_Connection):
 
     def __init__(self, host, port, username, password, ssh_key, ap):
         """Initialize the SSH connection properties."""
-        super(SshConnection, self).__init__()
+        super().__init__()
 
         self._ssh = None
         self._host = host
@@ -322,7 +304,7 @@ def connect(self):
             self._ssh.login(self._host, self._username,
                             password=self._password, port=self._port)
 
-        super(SshConnection, self).connect()
+        super().connect()
 
     def disconnect(self):   \
             # pylint: disable=broad-except
@@ -334,15 +316,15 @@ def disconnect(self):   \
         finally:
             self._ssh = None
 
-        super(SshConnection, self).disconnect()
+        super().disconnect()
 
 
 class TelnetConnection(_Connection):
     """Maintains a Telnet connection to an ASUS-WRT router."""
 
     def __init__(self, host, port, username, password, ap):
         """Initialize the Telnet connection properties."""
-        super(TelnetConnection, self).__init__()
+        super().__init__()
 
         self._telnet = None
         self._host = host
@@ -361,7 +343,6 @@ def run_command(self, command):
         try:
             if not self.connected:
                 self.connect()
-
             self._telnet.write('{}\n'.format(command).encode('ascii'))
             data = (self._telnet.read_until(self._prompt_string).
                     split(b'\n')[1:-1])
@@ -392,7 +373,7 @@ def connect(self):
         self._telnet.write((self._password + '\n').encode('ascii'))
         self._prompt_string = self._telnet.read_until(b'#').split(b'\n')[-1]
 
-        super(TelnetConnection, self).connect()
+        super().connect()
 
     def disconnect(self):   \
             # pylint: disable=broad-except
@@ -402,4 +383,4 @@ def disconnect(self):   \
         except Exception:
             pass
 
-        super(TelnetConnection, self).disconnect()
+        super().disconnect()