[Core] Refactor server argument choices (#36586)

test/manual/test_dsa_alias_cli_registry_env.py

@@ -21,29 +21,30 @@ sys.path.insert(0, os.path.join(os.path.dirname(__file__), "../../python"))
 
 
 class TestDSAChoicesAndFields(unittest.TestCase):
-    """Verify DSA_CHOICES constant and ServerArgs field renaming."""
+    """Verify DSA CLI choices and ServerArgs field renaming."""
 
     def setUp(self):
-        from sglang.srt.server_args import (
-            DSA_CHOICES,
-            NSA_CHOICES,
-            ServerArgs,
-        )
+        from sglang.srt.server_args import ServerArgs
 
         self.ServerArgs = ServerArgs
-        self.DSA_CHOICES = DSA_CHOICES
-        self.NSA_CHOICES = NSA_CHOICES
+        parser = argparse.ArgumentParser()
+        ServerArgs.add_cli_args(parser)
+        self.actions = {
+            option: action
+            for action in parser._actions
+            for option in action.option_strings
+        }
 
     def test_dsa_choices_is_canonical(self):
-        self.assertIn("fa3", self.DSA_CHOICES)
-        self.assertIn("tilelang", self.DSA_CHOICES)
-        self.assertIn("flashinfer_sparse_mla", self.DSA_CHOICES)
+        choices = self.actions["--dsa-prefill-backend"].choices
+        self.assertIn("fa3", choices)
+        self.assertIn("tilelang", choices)
+        self.assertIn("flashinfer_sparse_mla", choices)
 
-    def test_nsa_choices_is_alias(self):
-        self.assertIs(
-            self.NSA_CHOICES,
-            self.DSA_CHOICES,
-            "NSA_CHOICES must be the same object as DSA_CHOICES",
+    def test_nsa_choices_match_dsa_choices(self):
+        self.assertEqual(
+            self.actions["--nsa-prefill-backend"].choices,
+            self.actions["--dsa-prefill-backend"].choices,
         )
 
     def test_serverargs_has_dsa_fields(self):