diff --git a/irctest/numerics.py b/irctest/numerics.py
index 28006fe..8aafb08 100644
--- a/irctest/numerics.py
+++ b/irctest/numerics.py
@@ -66,6 +66,7 @@ RPL_WHOISIDLE = "317"
 RPL_ENDOFWHOIS = "318"
 RPL_WHOISCHANNELS = "319"
 RPL_WHOISSPECIAL = "320"
+RPL_LISTSTART = "321"
 RPL_LIST = "322"
 RPL_LISTEND = "323"
 RPL_CHANNELMODEIS = "324"
diff --git a/irctest/server_tests/list.py b/irctest/server_tests/list.py
index 9529cb9..3ef89d0 100644
--- a/irctest/server_tests/list.py
+++ b/irctest/server_tests/list.py
@@ -1,4 +1,5 @@
 from irctest import cases
+from irctest.numerics import RPL_LIST, RPL_LISTEND, RPL_LISTSTART
 
 
 class ListTestCase(cases.BaseServerTestCase):
@@ -6,26 +7,27 @@ class ListTestCase(cases.BaseServerTestCase):
     def testListEmpty(self):
         """<https://tools.ietf.org/html/rfc1459#section-4.2.6>
         <https://tools.ietf.org/html/rfc2812#section-3.2.6>
+        <https://modern.ircdocs.horse/#list-message>
         """
         self.connectClient("foo")
         self.connectClient("bar")
         self.getMessages(1)
         self.sendLine(2, "LIST")
         m = self.getMessage(2)
-        if m.command == "321":
-            # skip RPL_LISTSTART
+        if m.command == RPL_LISTSTART:
+            # skip
             m = self.getMessage(2)
         # skip local pseudo-channels listed by ngircd and ircu
-        while m.command == "322" and m.params[1].startswith("&"):
+        while m.command == RPL_LIST and m.params[1].startswith("&"):
             m = self.getMessage(2)
         self.assertNotEqual(
             m.command,
-            "322",  # RPL_LIST
+            RPL_LIST,
             "LIST response gives (at least) one channel, whereas there " "is none.",
         )
         self.assertMessageMatch(
             m,
-            command="323",  # RPL_LISTEND
+            command=RPL_LISTEND,
             fail_msg="Second reply to LIST is not 322 (RPL_LIST) "
             "or 323 (RPL_LISTEND), or but: {msg}",
         )
@@ -35,6 +37,8 @@ class ListTestCase(cases.BaseServerTestCase):
         """When a channel exists, LIST should get it in a reply.
         <https://tools.ietf.org/html/rfc1459#section-4.2.6>
         <https://tools.ietf.org/html/rfc2812#section-3.2.6>
+
+        <https://modern.ircdocs.horse/#list-message>
         """
         self.connectClient("foo")
         self.connectClient("bar")
@@ -42,34 +46,34 @@ class ListTestCase(cases.BaseServerTestCase):
         self.getMessages(1)
         self.sendLine(2, "LIST")
         m = self.getMessage(2)
-        if m.command == "321":
-            # skip RPL_LISTSTART
+        if m.command == RPL_LISTSTART:
+            # skip
             m = self.getMessage(2)
         self.assertNotEqual(
             m.command,
-            "323",  # RPL_LISTEND
+            RPL_LISTEND,
             fail_msg="LIST response ended (ie. 323, aka RPL_LISTEND) "
             "without listing any channel, whereas there is one.",
         )
         self.assertMessageMatch(
             m,
-            command="322",  # RPL_LIST
+            command=RPL_LIST,
             fail_msg="Second reply to LIST is not 322 (RPL_LIST), "
             "nor 323 (RPL_LISTEND) but: {msg}",
         )
         m = self.getMessage(2)
         # skip local pseudo-channels listed by ngircd and ircu
-        while m.command == "322" and m.params[1].startswith("&"):
+        while m.command == RPL_LIST and m.params[1].startswith("&"):
             m = self.getMessage(2)
         self.assertNotEqual(
             m.command,
-            "322",  # RPL_LIST
+            RPL_LIST,
             fail_msg="LIST response gives (at least) two channels, "
             "whereas there is only one.",
         )
         self.assertMessageMatch(
             m,
-            command="323",  # RPL_LISTEND
+            command=RPL_LISTEND,
             fail_msg="Third reply to LIST is not 322 (RPL_LIST) "
             "or 323 (RPL_LISTEND), or but: {msg}",
         )