Update generate scripts and tls13 test cases

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/tests/scripts/generate_tls13_compat_tests.py b/tests/scripts/generate_tls13_compat_tests.py
index 2e34ebb..103de69 100755
--- a/tests/scripts/generate_tls13_compat_tests.py
+++ b/tests/scripts/generate_tls13_compat_tests.py
@@ -44,6 +44,8 @@
     )
 }
 
+
+
 CAFILE = {
     'ecdsa_secp256r1_sha256': 'data_files/test-ca2.crt',
     'ecdsa_secp384r1_sha384': 'data_files/test-ca2.crt',
@@ -74,6 +76,7 @@
     'x448': 0x1e,
 }
 
+OUTPUT_FILE=sys.stdout
 
 def remove_duplicates(seq):
     seen = set()
@@ -365,15 +368,45 @@
         server.cmd()), '"{}"'.format(client.cmd()), '0']
     cmd += server.post_checks()
     cmd += client.post_checks()
-    prefix = ' \\\n' + (' '*12)
+    prefix = ' \\\n' + (' '*9)
     cmd = prefix.join(cmd)
-    print('\n'.join(server.pre_checks() + client.pre_checks() + [cmd]))
-    return 0
+    return '\n'.join(server.pre_checks() + client.pre_checks() + [cmd])
 
+SSL_OUTPUT_HEADER='''#!/bin/sh
+
+# {filename}
+#
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Purpose
+#
+# List TLS1.3 compat test cases. They are generated by
+# `generate_tls13_compat_tests.py -a`.
+#
+# PLEASE DO NOT EDIT THIS FILE. IF NEEDED, PLEASE MODIFY `generate_tls13_compat_tests.py`
+# AND REGENERATE THIS FILE.
+#
+'''
 
 def main():
     parser = argparse.ArgumentParser()
 
+    parser.add_argument('-o', '--output', nargs='?',
+                        default=None, help='Output file path')
+
     parser.add_argument('-a', '--generate-all-tls13-compat-tests', action='store_true',
                         default=False, help='Generate all available tls13 compat tests')
 
@@ -409,29 +442,35 @@
                         help='Choose cipher suite for test')
 
     args = parser.parse_args()
+    if args.output:
+        OUTPUT_FILE=open(args.output,'w')
+        OUTPUT_FILE.write(SSL_OUTPUT_HEADER.format(filename=args.output))
+
     if args.generate_all_tls13_compat_tests:
         for i in itertools.product(CIPHER_SUITE_IANA_VALUE.keys(), SIG_ALG_IANA_VALUE.keys(),
                                    NAMED_GROUP_IANA_VALUE.keys(), SERVER_CLS.keys(),
                                    CLIENT_CLS.keys()):
-            generate_compat_test(
-                **dict(zip(['cipher', 'sig_alg', 'named_group', 'server', 'client'], i)))
-            print()
+            test_case = generate_compat_test( **dict(
+                zip(['cipher', 'sig_alg', 'named_group', 'server', 'client'], i)))
+            print(test_case,file=OUTPUT_FILE)
         return 0
 
     if args.list_ciphers or args.list_sig_algs or args.list_named_groups \
             or args.list_servers or args.list_clients:
         if args.list_ciphers:
-            print(*CIPHER_SUITE_IANA_VALUE.keys())
+            print(*CIPHER_SUITE_IANA_VALUE.keys(),file=OUTPUT_FILE)
         if args.list_sig_algs:
-            print(*SIG_ALG_IANA_VALUE.keys())
+            print(*SIG_ALG_IANA_VALUE.keys(),file=OUTPUT_FILE)
         if args.list_named_groups:
-            print(*NAMED_GROUP_IANA_VALUE.keys())
+            print(*NAMED_GROUP_IANA_VALUE.keys(),file=OUTPUT_FILE)
         if args.list_servers:
-            print(*SERVER_CLS.keys())
+            print(*SERVER_CLS.keys(),file=OUTPUT_FILE)
         if args.list_clients:
-            print(*CLIENT_CLS.keys())
+            print(*CLIENT_CLS.keys(),file=OUTPUT_FILE)
         return 0
-    return generate_compat_test(**vars(args))
+
+    print(generate_compat_test(**vars(args)),file=OUTPUT_FILE)
+    return 0
 
 
 if __name__ == "__main__":