raw printer

this printer preserves all whitespaces and comments in original meson.build file. It will be useful for rewrite and potential auto-formatter

1 files changed, 22 insertions, 0 deletions

diff --git a/unittests/rewritetests.py b/unittests/rewritetests.py
index ca30fe9..c338844 100644
--- a/unittests/rewritetests.py
+++ b/unittests/rewritetests.py
@@ -13,11 +13,15 @@
 # limitations under the License.
 
 import subprocess
+from itertools import zip_longest
 import json
 import os
+from pathlib import Path
 import shutil
 import unittest
 
+from mesonbuild.ast import IntrospectionInterpreter, AstIDGenerator
+from mesonbuild.ast.printer import RawPrinter
 from mesonbuild.mesonlib import windows_proof_rmtree
 from .baseplatformtests import BasePlatformTests
 
@@ -396,3 +400,21 @@ class RewriterTests(BasePlatformTests):
         # Check the written file
         out = self.rewrite(self.builddir, os.path.join(self.builddir, 'info.json'))
         self.assertDictEqual(out, expected)
+
+    def test_raw_printer_is_idempotent(self):
+        test_path = Path(self.unit_test_dir, '118 rewrite')
+        meson_build_file = test_path / 'meson.build'
+        # original_contents = meson_build_file.read_bytes()
+        original_contents = meson_build_file.read_text(encoding='utf-8')
+
+        interpreter = IntrospectionInterpreter(test_path, '', 'ninja', visitors = [AstIDGenerator()])
+        interpreter.analyze()
+
+        printer = RawPrinter()
+        interpreter.ast.accept(printer)
+        # new_contents = printer.result.encode('utf-8')
+        new_contents = printer.result
+
+        # Do it line per line because it is easier to debug like that
+        for orig_line, new_line in zip_longest(original_contents.splitlines(), new_contents.splitlines()):
+            self.assertEqual(orig_line, new_line)