Move token generation to auth handler

I prefer the auth handler to worry about all auth, and register to call
into it as needed, than to smatter auth logic between the two.

tests/handlers/test_auth.py

@@ -0,0 +1,70 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import pymacaroons
+
+from mock import Mock, NonCallableMock
+from synapse.handlers.auth import AuthHandler
+from tests import unittest
+from tests.utils import setup_test_homeserver
+from twisted.internet import defer
+
+
+class AuthHandlers(object):
+    def __init__(self, hs):
+        self.auth_handler = AuthHandler(hs)
+
+
+class AuthTestCase(unittest.TestCase):
+    @defer.inlineCallbacks
+    def setUp(self):
+        self.hs = yield setup_test_homeserver(handlers=None)
+        self.hs.handlers = AuthHandlers(self.hs)
+
+    def test_token_is_a_macaroon(self):
+        self.hs.config.macaroon_secret_key = "this key is a huge secret"
+
+        token = self.hs.handlers.auth_handler.generate_access_token("some_user")
+        # Check that we can parse the thing with pymacaroons
+        macaroon = pymacaroons.Macaroon.deserialize(token)
+        # The most basic of sanity checks
+        if "some_user" not in macaroon.inspect():
+            self.fail("some_user was not in %s" % macaroon.inspect())
+
+    def test_macaroon_caveats(self):
+        self.hs.config.macaroon_secret_key = "this key is a massive secret"
+        self.hs.clock.now = 5000
+
+        token = self.hs.handlers.auth_handler.generate_access_token("a_user")
+        macaroon = pymacaroons.Macaroon.deserialize(token)
+
+        def verify_gen(caveat):
+            return caveat == "gen = 1"
+
+        def verify_user(caveat):
+            return caveat == "user_id = a_user"
+
+        def verify_type(caveat):
+            return caveat == "type = access"
+
+        def verify_expiry(caveat):
+            return caveat == "time < 8600000"
+
+        v = pymacaroons.Verifier()
+        v.satisfy_general(verify_gen)
+        v.satisfy_general(verify_user)
+        v.satisfy_general(verify_type)
+        v.satisfy_general(verify_expiry)
+        v.verify(macaroon, self.hs.config.macaroon_secret_key)