Require port and server_port interop flags

Also sort arguments to ArgumentParser.add_argument in idiomatic order.

src/python/grpcio_tests/tests/interop/client.py

@@ -29,37 +29,40 @@ def _args():
     parser = argparse.ArgumentParser()
     parser.add_argument(
         '--server_host',
-        help='the host to which to connect',
+        default="localhost",
         type=str,
-        default="localhost")
+        help='the host to which to connect')
     parser.add_argument(
-        '--server_port', help='the port to which to connect', type=int)
+        '--server_port',
+        type=int,
+        required=True,
+        help='the port to which to connect')
     parser.add_argument(
         '--test_case',
-        help='the test case to execute',
+        default='large_unary',
         type=str,
-        default="large_unary")
+        help='the test case to execute')
     parser.add_argument(
         '--use_tls',
-        help='require a secure connection',
         default=False,
-        type=resources.parse_bool)
+        type=resources.parse_bool,
+        help='require a secure connection')
     parser.add_argument(
         '--use_test_ca',
-        help='replace platform root CAs with ca.pem',
         default=False,
-        type=resources.parse_bool)
+        type=resources.parse_bool,
+        help='replace platform root CAs with ca.pem')
     parser.add_argument(
         '--server_host_override',
         default="foo.test.google.fr",
-        help='the server host to which to claim to connect',
-        type=str)
+        type=str,
+        help='the server host to which to claim to connect')
     parser.add_argument(
-        '--oauth_scope', help='scope for OAuth tokens', type=str)
+        '--oauth_scope', type=str, help='scope for OAuth tokens')
     parser.add_argument(
         '--default_service_account',
-        help='email address of the default service account',
-        type=str)
+        type=str,
+        help='email address of the default service account')
     return parser.parse_args()
 
 

src/python/grpcio_tests/tests/interop/server.py

@@ -29,12 +29,13 @@ _ONE_DAY_IN_SECONDS = 60 * 60 * 24
 
 def serve():
     parser = argparse.ArgumentParser()
-    parser.add_argument('--port', help='the port on which to serve', type=int)
+    parser.add_argument(
+        '--port', type=int, required=True, help='the port on which to serve')
     parser.add_argument(
         '--use_tls',
-        help='require a secure connection',
         default=False,
-        type=resources.parse_bool)
+        type=resources.parse_bool,
+        help='require a secure connection')
     args = parser.parse_args()
 
     server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))