Add SETNAME tests (#209)

* Add SETNAME tests

* fix race condition

* fix synchronization issue

sendLine does not synchronize by itself; call getMessage to synchronize
and test the message since we have it

* Update irctest/server_tests/setname.py

Co-authored-by: Val Lorentz <progval+github@progval.net>

---------

Co-authored-by: Shivaram Lingamneni <slingamn@cs.stanford.edu>
Co-authored-by: Val Lorentz <progval+github@progval.net>

irctest/server_tests/setname.py

@@ -0,0 +1,65 @@
+"""
+`IRCv3 SETNAME<https://ircv3.net/specs/extensions/setname>`_
+"""
+
+from irctest import cases
+from irctest.numerics import RPL_WHOISUSER
+
+
+class SetnameMessageTestCase(cases.BaseServerTestCase):
+    @cases.mark_specifications("IRCv3")
+    @cases.mark_capabilities("setname")
+    def testSetnameMessage(self):
+        self.connectClient("foo", capabilities=["setname"], skip_if_cap_nak=True)
+
+        self.sendLine(1, "SETNAME bar")
+        self.assertMessageMatch(
+            self.getMessage(1),
+            command="SETNAME",
+            params=["bar"],
+        )
+
+        self.sendLine(1, "WHOIS foo")
+        whoisuser = [m for m in self.getMessages(1) if m.command == RPL_WHOISUSER][0]
+        self.assertEqual(whoisuser.params[-1], "bar")
+
+    @cases.mark_specifications("IRCv3")
+    @cases.mark_capabilities("setname")
+    def testSetnameChannel(self):
+        """“[Servers] MUST send the server-to-client version of the
+        SETNAME message to all clients in common channels, as well as
+        to the client from which it originated, to confirm the change
+        has occurred.
+
+        The SETNAME message MUST NOT be sent to clients which do not
+        have the setname capability negotiated.“
+        """
+        self.connectClient("foo", capabilities=["setname"], skip_if_cap_nak=True)
+        self.connectClient("bar", capabilities=["setname"], skip_if_cap_nak=True)
+        self.connectClient("baz")
+
+        self.joinChannel(1, "#chan")
+        self.joinChannel(2, "#chan")
+        self.joinChannel(3, "#chan")
+        self.getMessages(1)
+        self.getMessages(2)
+        self.getMessages(3)
+
+        self.sendLine(1, "SETNAME qux")
+        self.assertMessageMatch(
+            self.getMessage(1),
+            command="SETNAME",
+            params=["qux"],
+        )
+
+        self.assertMessageMatch(
+            self.getMessage(2),
+            command="SETNAME",
+            params=["qux"],
+        )
+
+        self.assertEqual(
+            self.getMessages(3),
+            [],
+            "Got SETNAME response when it was not negotiated",
+        )