fix test failure

Author: shenxianpeng

README.md

@@ -155,7 +155,7 @@ Use -header-filter=.* to display errors from all non-system headers. Use -system
 
 ### Debugging `clang-format` hook
 
-If you encounter issues with the clang-format hook (such as exit code 247 or other errors), you can enable verbose output to show the list of processed files.
+If you encounter issues with the clang-format hook (such as exit code 247 or other errors), you can enable verbose output to show the list of processed files by passing the `-v` or `--verbose` argument in the `args` section.
 
 ```yaml
 repos:

cpp_linter_hooks/clang_format.py

@@ -22,11 +22,11 @@ def run_clang_format(args=None) -> Tuple[int, str]:
     output = ""
     try:
         if "--dry-run" in command:
-            sp = subprocess.run(command, stdout=subprocess.PIPE, encoding="utf-8")
+            sp = subprocess.run(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, encoding="utf-8")
             retval = -1  # Not a fail just identify it's a dry-run.
-            output = sp.stdout
+            output = sp.stdout + sp.stderr
         else:
-            retval = subprocess.run(command, stdout=subprocess.PIPE).returncode
+            retval = subprocess.run(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE).returncode
         return retval, output
     except FileNotFoundError as stderr:
         retval = 1

testing/pre-commit-config-verbose.yaml

@@ -4,3 +4,8 @@ repos:
     hooks:
       - id: clang-format
         args: [--style=file, --version=16, --verbose]  # test with verbose output
+  - repo: .
+    rev: HEAD
+    hooks:
+      - id: clang-format
+        args: [--style=file, --version=16, -v]  # test with verbose output

tests/test_clang_format.py

@@ -73,7 +73,7 @@ def test_run_clang_format_verbose(tmp_path):
     test_file.write_bytes(Path("testing/main.c").read_bytes())
 
     # Test with verbose flag
-    ret, output = run_clang_format(["--verbose", "--style=Google", str(test_file)])
+    ret, _ = run_clang_format(["--verbose", "--style=Google", str(test_file)])
 
     # Should succeed
     assert ret == 0