New script to determine PSA crypto test dependencies automatically

This commit only contains a framework to rewrite .data files. No
actual modification of the content is implemented yet.

For now, command line parsing is trivial: just a list of file names,
with no options.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

tests/scripts/set_psa_test_dependencies.py

@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+
+"""Edit test cases to use PSA dependencies instead of classic dependencies.
+"""
+
+# 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.
+
+import os
+import sys
+
+def process_data_stanza(stanza, file_name, test_case_number):
+    """Update PSA crypto dependencies in one Mbed TLS test case.
+
+    stanza is the test case text (including the description, the dependencies,
+    the line with the function and arguments, and optionally comments). Return
+    a new stanza with an updated dependency line, preserving everything else
+    (description, comments, arguments, etc.).
+    """
+    #TODO: not implemented yet
+    return stanza
+
+def process_data_file(file_name, old_content):
+    """Update PSA crypto dependencies in an Mbed TLS test suite data file.
+
+    Process old_content (the old content of the file) and return the new content.
+    """
+    old_stanzas = old_content.split('\n\n')
+    new_stanzas = [process_data_stanza(stanza, file_name, n)
+                   for n, stanza in enumerate(old_stanzas, start=1)]
+    return '\n\n'.join(new_stanzas)
+
+def update_file(file_name, old_content, new_content):
+    """Update the given file with the given new content.
+
+    Replace the existing file. The previous version is renamed to *.bak.
+    Don't modify the file if the content was unchanged.
+    """
+    if new_content == old_content:
+        return
+    backup = file_name + '.bak'
+    tmp = file_name + '.tmp'
+    with open(tmp, 'w', encoding='utf-8') as new_file:
+        new_file.write(new_content)
+    os.replace(file_name, backup)
+    os.replace(tmp, file_name)
+
+def process_file(file_name):
+    """Update PSA crypto dependencies in an Mbed TLS test suite data file.
+
+    Replace the existing file. The previous version is renamed to *.bak.
+    Don't modify the file if the content was unchanged.
+    """
+    old_content = open(file_name, encoding='utf-8').read()
+    if file_name.endswith('.data'):
+        new_content = process_data_file(file_name, old_content)
+    else:
+        raise Exception('File type not recognized: {}'
+                        .format(file_name))
+    update_file(file_name, old_content, new_content)
+
+def main(args):
+    for file_name in args:
+        process_file(file_name)
+
+if __name__ == '__main__':
+    main(sys.argv[1:])