Improve handling of missing players:

 * Tighten `SqueezeboxPlayerSettings` constructor to only allow valid objects (i.e. must find a `playerid` - there could be a parsing bug here somewhere, so let's find it early rather than via `__str__` later...
 * Die explicitly if there are no players found (we can't do anything much in the skill...). Fixes #56.
 * Check for missing DEFAULT_PLAYER and default to first (Fixes #59)
 * Improve log messages a bit

squeezealexa/squeezebox/server.py

@@ -12,7 +12,7 @@
 
 import time
 
-from squeezealexa.utils import with_example, print_d, stronger
+from squeezealexa.utils import with_example, print_d, stronger, print_w
 
 import urllib.request as urllib
 
@@ -24,8 +24,14 @@ class SqueezeboxException(Exception):
 class SqueezeboxPlayerSettings(dict):
     """Encapsulates player settings"""
 
+    def __init__(self, data: dict):
+        super().__init__(data)
+        if 'playerid' not in data:
+            raise SqueezeboxException(
+                "Couldn't find a playerid in {}".format(data))
+
     @property
-    def id(self):
+    def id(self) -> str:
         return self['playerid']
 
     def __getattr__(self, key):
@@ -58,8 +64,19 @@ def __init__(self, transport, user=None, password=None,
             print_d("Authenticated with %s!" % self)
         self.players = {}
         self.refresh_status()
-        self.cur_player_id = pid = cur_player_id or list(self.players)[0]
-        print_d("Default player is now %s" % (self.players[pid],))
+        players = list(self.players.values())
+        if not players:
+            raise SqueezeboxException("Uh-oh. No players found.")
+        if not cur_player_id:
+            self.cur_player_id = players[0].id
+        elif cur_player_id not in self.players:
+            print_w("Couldn't find player {id} (found: {all}). "
+                    "Check your DEFAULT_PLAYER config.",
+                    id=cur_player_id, all=", ".join(list(self.players.keys())))
+            self.cur_player_id = players[0].id
+        else:
+            self.cur_player_id = cur_player_id
+        print_d("Current player is now: {}", self.players[self.cur_player_id])
         self.__genres = []
         self.__playlists = []
         self.__favorites = []

squeezealexa/transport/base.py

@@ -13,7 +13,7 @@
 
 class Error(Exception):
 
-    def __init__(self, msg, e):
+    def __init__(self, msg, e=None):
         super(Error, self).__init__(msg)
         self.message = msg
         self.__cause__ = e

tests/test_server.py

@@ -12,14 +12,46 @@
 
 from unittest import TestCase
 
-from squeezealexa.squeezebox.server import Server
+from pytest import raises
+
+from squeezealexa.squeezebox.server import Server, SqueezeboxPlayerSettings, \
+    SqueezeboxException
 from tests.fake_ssl import FakeTransport, FAKE_LENGTH, A_REAL_STATUS
 
 
-class TestServer(TestCase):
+class TestSqueezeboxPlayerSettings:
+    def test_raises_if_no_playerid_found(self):
+        with raises(SqueezeboxException) as e:
+            SqueezeboxPlayerSettings({})
+        assert "couldn't find a playerid" in str(e).lower()
+
+
+class NoRefreshServer(Server):
+    """A normal server, that has no transport never returns any players"""
+
+    def __init__(self, user=None, password=None, cur_player_id=None):
+        super().__init__(None, user, password, cur_player_id, False)
+
+    def refresh_status(self):
+        self.players = {}
+
+
+class TestServerNoTransport:
+    def test_no_players_raises(self):
+        with raises(SqueezeboxException) as e:
+            NoRefreshServer()
+        assert "no players" in str(e).lower()
+
+
+class TestServerWithTransport(TestCase):
     def setUp(self):
         self.server = Server(transport=FakeTransport())
 
+    def test_unknown_default_player(self):
+        transport = FakeTransport(fake_id="foo")
+        self.server = Server(transport=transport, cur_player_id="GONE")
+        assert self.server.cur_player_id == "foo"
+
     def test_get_current(self):
         assert self.server.get_status()['genre']