mdata: Add test to ensure mesondata.py is up-to-date

run_unittests.py

@@ -1485,6 +1485,38 @@ class DataTests(unittest.TestCase):
         astint = AstInterpreter('.', '', '')
         self.assertEqual(set(interp.funcs.keys()), set(astint.funcs.keys()))
 
+    def test_mesondata_is_up_to_date(self):
+        from mesonbuild.mesondata import mesondata
+        err_msg = textwrap.dedent('''
+
+            ###########################################################
+            ###        mesonbuild.mesondata is not up-to-date       ###
+            ###  Please regenerate it by running tools/gen_data.py  ###
+            ###########################################################
+
+        ''')
+
+        root_dir = Path(__file__).resolve().parent
+        mesonbuild_dir = root_dir / 'mesonbuild'
+
+        data_dirs = mesonbuild_dir.glob('**/data')
+        data_files = []  # type: T.List[T.Tuple(str, str)]
+
+        for i in data_dirs:
+            for p in i.iterdir():
+                data_files += [(p.relative_to(mesonbuild_dir).as_posix(), hashlib.sha256(p.read_bytes()).hexdigest())]
+
+        from pprint import pprint
+        current_files = set(mesondata.keys())
+        scanned_files = set([x[0] for x in data_files])
+
+        self.assertSetEqual(current_files, scanned_files, err_msg + 'Data files were added or removed\n')
+        errors = []
+        for i in data_files:
+            if mesondata[i[0]].sha256sum != i[1]:
+                errors += [i[0]]
+
+        self.assertListEqual(errors, [], err_msg + 'Files were changed')
 
 class BasePlatformTests(unittest.TestCase):
     prefix = '/usr'