fix: capture output and patch test's mocks

Author: 2bndy5

cpp_linter_hooks/util.py

@@ -61,17 +61,16 @@ def parse_version(v: str):
 
 def _install_tool(tool: str, version: str) -> Optional[Path]:
     """Install a tool using pip, suppressing output."""
-    try:
-        subprocess.run(
-            [sys.executable, "-m", "pip", "install", f"{tool}=={version}"],
-            capture_output=True,
-            check=True,
-        )
+    result = subprocess.run(
+        [sys.executable, "-m", "pip", "install", f"{tool}=={version}"],
+        capture_output=True,
+    )
+    if result.returncode == 0:
         return shutil.which(tool)
-    except subprocess.CalledProcessError as e:
+    else:
         LOG.error("pip failed to install %s %s", tool, version)
-        LOG.error(e.stdout.decode(encoding="utf-8"))
-        LOG.error(e.stderr.decode(encoding="utf-8"))
+        LOG.error(result.stdout.decode(encoding="utf-8"))
+        LOG.error(result.stderr.decode(encoding="utf-8"))
         return None
 
 

tests/test_util.py

@@ -123,8 +123,11 @@ def test_install_tool_success():
     """Test _install_tool successful installation."""
     mock_path = "/usr/bin/clang-format"
 
+    def patched_run(*args, **kwargs):
+        return subprocess.CompletedProcess(args, returncode=0)
+
     with (
-        patch("subprocess.run") as mock_run,
+        patch("subprocess.run", side_effect=patched_run) as mock_run,
         patch("shutil.which", return_value=mock_path),
     ):
         result = _install_tool("clang-format", "20.1.7")
@@ -133,18 +136,20 @@ def test_install_tool_success():
         mock_run.assert_called_once_with(
             [sys.executable, "-m", "pip", "install", "clang-format==20.1.7"],
             capture_output=True,
-            check=True,
         )
 
 
 @pytest.mark.benchmark
 def test_install_tool_failure():
     """Test _install_tool when pip install fails."""
+
+    def patched_run(*args, **kwargs):
+        return subprocess.CompletedProcess(
+            args, returncode=1, stderr=b"Error", stdout=b"Installation failed"
+        )
+
     with (
-        patch(
-            "subprocess.run",
-            side_effect=subprocess.CalledProcessError(1, ["pip"]),
-        ),
+        patch("subprocess.run", side_effect=patched_run),
         patch("cpp_linter_hooks.util.LOG"),
     ):
         result = _install_tool("clang-format", "20.1.7")