Test that the generated files are up to date

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

Author: gilles-peskine-arm

scripts/mbedtls_framework/test_config_checks_generator.py

@@ -4,12 +4,17 @@
 ## Copyright The Mbed TLS Contributors
 ## SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 
+import glob
 import os
+import re
 import subprocess
 import sys
+import tempfile
 import unittest
 from typing import List, Optional, Pattern, Union
 
+from . import config_checks_generator
+
 
 class TestConfigChecks(unittest.TestCase):
     """Unit tests for checks generated by config_checks_generator."""
@@ -63,6 +68,7 @@ def run_with_config_files(self,
         if mbedtls_user_config_file is not None:
             cmd.append(f'-DMBEDTLS_USER_CONFIG_FILE="{mbedtls_user_config_file}"')
         cmd += extra_options
+        assert self.PROJECT_CONFIG_C is not None
         cmd += ['-Iinclude', '-Idrivers/builtin/include', '-I.',
                 '-I' + os.path.dirname(self.PROJECT_CONFIG_C),
                 self.PROJECT_CONFIG_C]
@@ -149,3 +155,45 @@ def test_nominal(self) -> None:
     def test_error(self) -> None:
         self.bad_case('#error "Bad crypto configuration"',
                       error='"Bad crypto configuration"')
+
+    @staticmethod
+    def normalize_generated_file_content(content) -> None:
+        """Normalize the content of a generated file.
+
+        The file content is mostly deterministic, but it includes the
+        name of the program that generated it. That name is different
+        when we generate it from the test code, so we erase the program
+        name from the content.
+        """
+        return re.sub(r'([Gg]enerated by )\S+(\.py\W*\s)',
+                      r'\1normalized\2',
+                      content)
+
+    def check_generated_file(self,
+                             production_directory: str,
+                             new_file: str) -> None:
+        """Check whether a generated file is up to date."""
+        production_file = os.path.join(production_directory,
+                                       os.path.basename(new_file))
+        self.assertTrue(os.path.exists(production_file))
+        with open(new_file) as inp:
+            new_content = inp.read()
+        with open(production_file) as inp:
+            production_content = inp.read()
+        # The second line contains "generated by test_script.py" here
+        # but "generated by production_script.py" in the production
+        # file. Everything else should be identical.
+        self.assertEqual(
+            self.normalize_generated_file_content(new_content),
+            self.normalize_generated_file_content(production_content))
+
+    def up_to_date_case(self,
+                        production_data: config_checks_generator.BranchData
+                        ) -> None:
+        """Check whether the generated files are up to date."""
+        with tempfile.TemporaryDirectory() as temp_dir:
+            temp_data = production_data._replace(header_directory=temp_dir)
+            config_checks_generator.generate_header_files(os.curdir, temp_data)
+            for new_file in glob.glob(temp_dir + '/*'):
+                self.check_generated_file(production_data.header_directory,
+                                          new_file)