diff --git a/irctest/cases.py b/irctest/cases.py
index 03201c6..6d00d0e 100644
--- a/irctest/cases.py
+++ b/irctest/cases.py
@@ -6,7 +6,9 @@ from .irc_utils import message_parser
 class _IrcTestCase(unittest.TestCase):
     controllerClass = None # Will be set by __main__.py
 
-class ClientTestCase(_IrcTestCase):
+class BaseClientTestCase(_IrcTestCase):
+    """Basic class for client tests. Handles spawning a client and getting
+    messages from it."""
     def setUp(self):
         self.controller = self.controllerClass()
         self._setUpServer()
@@ -30,3 +32,26 @@ class ClientTestCase(_IrcTestCase):
         return self.conn_file.readline().strip()
     def getMessage(self):
         return message_parser.parse_message(self.conn_file.readline())
+
+class NegociationHelper:
+    """Helper class for tests handling capabilities negociation."""
+    def readCapLs(self):
+        (hostname, port) = self.server.getsockname()
+        self.controller.run(
+                hostname=hostname,
+                port=port,
+                authentication=None,
+                )
+        self.acceptClient()
+        m = self.getMessage()
+        self.assertEqual(m.command, 'CAP',
+                'First message is not CAP LS.')
+        self.assertEqual(m.subcommand, 'LS',
+                'First message is not CAP LS.')
+        if m.params == []:
+            self.protocol_version = 301
+        elif m.params == ['302']:
+            self.protocol_version = 302
+        else:
+            raise AssertionError('Unknown protocol version {}'
+                    .format(m.params))
diff --git a/irctest/clienttests/test_cap.py b/irctest/clienttests/test_cap.py
index 23c24dd..5577ce5 100644
--- a/irctest/clienttests/test_cap.py
+++ b/irctest/clienttests/test_cap.py
@@ -1,18 +1,6 @@
-from irctest.cases import ClientTestCase
+from irctest import cases
 from irctest.irc_utils.message_parser import Message
 
-class CapTestCase(ClientTestCase):
+class CapTestCase(cases.BaseClientTestCase, cases.NegociationHelper):
     def testSendCap(self):
-        (hostname, port) = self.server.getsockname()
-        self.controller.run(
-                hostname=hostname,
-                port=port,
-                authentication=None,
-                )
-        self.acceptClient()
-        m = self.getMessage()
-        self.assertEqual(m.command, 'CAP',
-                'First message is not CAP LS.')
-        self.assertEqual(m.subcommand, 'LS',
-                'First message is not CAP LS.')
-        self.assertIn(m.params, ([], ['302'])) # IRCv3.1 or IRVv3.2
+        self.readCapLs()