Print diff for debugging macos

tests/__init__.py

@@ -3,6 +3,7 @@
 from pathlib import Path
 import re
 from typing import Dict, List
+from difflib import context_diff
 
 import pytest
 
@@ -68,6 +69,13 @@ def check_reference_directory(
                     del test_lines[line_index], reference_lines[line_index]
 
                 cwd = Path.cwd()
-                assert '\n'.join(test_lines) == '\n'.join(
-                    reference_lines
-                ), f'"{os.path.relpath(test_filename, cwd)}" != "{os.path.relpath(reference_filename, cwd)}"'
+
+                assert '\n'.join(test_lines) == '\n'.join(reference_lines), ''.join(
+                    context_diff(
+                        test_lines,
+                        reference_lines,
+                        fromfile=str(test_filename),
+                        tofile=str(reference_filename),
+                        lineterm='',
+                    )
+                )