don't gracefully handle spaces in non-last param, throw ValueError

irctokens/protocol.py

@@ -81,9 +81,9 @@ class Line(object):
             last = params.pop(-1)
             for param in params:
                 if " " in param:
-                    outs.extend(param.split(" "))
-                else:
-                    outs.append(param)
+                    raise ValueError(
+                        "Spaces are not permitted in non-last params")
+            outs.extend(params)
 
             if " " in last:
                 last = f":{last}"

test/format.py

@@ -43,5 +43,6 @@ class FormatTestTrailing(unittest.TestCase):
 
 class FormatTestSpacedArg(unittest.TestCase):
     def test(self):
-        line = irctokens.format("USER", ["user", "0 *", "real name"])
-        self.assertEqual(line, "USER user 0 * :real name")
+        def _inner():
+            irctokens.format("USER", ["user", "0 *", "real name"])
+        self.assertRaises(ValueError, _inner)