New framework for generating PSA test cases automatically

This commit creates a script to generate test cases automatically
based on enumerating PSA key types, algorithms and other
classifications of cryptographic mechanisms.

Subsequent commits will implement the generation of test cases.

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

tests/scripts/generate_psa_tests.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+"""Generate test data for PSA cryptographic mechanisms.
+"""
+
+# 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 argparse
+import sys
+from typing import TypeVar
+
+import scripts_path # pylint: disable=unused-import
+from mbedtls_dev import macro_collector
+
+T = TypeVar('T') #pylint: disable=invalid-name
+
+class TestGenerator:
+    """Gather information and generate test data."""
+
+    def __init__(self, options):
+        self.test_suite_directory = self.get_option(options, 'directory',
+                                                    'tests/suites')
+        self.constructors = self.read_psa_interface()
+
+    @staticmethod
+    def get_option(options, name: str, default: T) -> T:
+        value = getattr(options, name, None)
+        return default if value is None else value
+
+    @staticmethod
+    def remove_unwanted_macros(
+            constructors: macro_collector.PSAMacroCollector
+    ) -> None:
+        # Mbed TLS doesn't support DSA. Don't attempt to generate any related
+        # test case.
+        constructors.key_types.discard('PSA_KEY_TYPE_DSA_KEY_PAIR')
+        constructors.key_types.discard('PSA_KEY_TYPE_DSA_PUBLIC_KEY')
+        constructors.algorithms_from_hash.pop('PSA_ALG_DSA', None)
+        constructors.algorithms_from_hash.pop('PSA_ALG_DETERMINISTIC_DSA', None)
+
+    def read_psa_interface(self) -> macro_collector.PSAMacroCollector:
+        """Return the list of known key types, algorithms, etc."""
+        constructors = macro_collector.PSAMacroCollector()
+        header_file_names = ['include/psa/crypto_values.h',
+                             'include/psa/crypto_extra.h']
+        for header_file_name in header_file_names:
+            with open(header_file_name, 'rb') as header_file:
+                constructors.read_file(header_file)
+        self.remove_unwanted_macros(constructors)
+        return constructors
+
+def main(args):
+    """Command line entry point."""
+    parser = argparse.ArgumentParser(description=__doc__)
+    options = parser.parse_args(args)
+    generator = TestGenerator(options)
+
+if __name__ == '__main__':
+    main(sys.argv[1:])