kunit: tool: skip stty when stdin is not a tty

run_kernel() cleanup and signal_handler() invoke stty unconditionally.
When stdin is not a tty (for example in CI or unit tests), this writes
noise to stderr.

Call stty only when stdin is a tty.

Add regression tests for these paths:
- run_kernel() with non-tty stdin
- signal_handler() with non-tty stdin
- signal_handler() with tty stdin

Signed-off-by: Shuvam Pandey <shuvampandey1@gmail.com>
Reviewed-by: David Gow <david@davidgow.net>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
index 2998e1bc088b28f73f5377826f682230a6f3ce1a..b610fcf0715a09ab1c8d134fedf54db0cec50ab3 100644 (file)
--- a/tools/testing/kunit/kunit_kernel.py
+++ b/tools/testing/kunit/kunit_kernel.py
@@ -345,6 +345,12 @@ class LinuxSourceTree:
                        return False
                return self.validate_config(build_dir)
 
+       def _restore_terminal_if_tty(self) -> None:
+               # stty requires a controlling terminal; skip headless runs.
+               if sys.stdin is None or not sys.stdin.isatty():
+                       return
+               subprocess.call(['stty', 'sane'])
+
        def run_kernel(self, args: Optional[List[str]]=None, build_dir: str='', filter_glob: str='', filter: str='', filter_action: Optional[str]=None, timeout: Optional[int]=None) -> Iterator[str]:
                # Copy to avoid mutating the caller-supplied list. exec_tests() reuses
                # the same args across repeated run_kernel() calls (e.g. --run_isolated),
@@ -386,8 +392,8 @@ class LinuxSourceTree:
                        process.stdout.close()
 
                        waiter.join()
-                       subprocess.call(['stty', 'sane'])
+                       self._restore_terminal_if_tty()
 
        def signal_handler(self, unused_sig: int, unused_frame: Optional[FrameType]) -> None:
                logging.error('Build interruption occurred. Cleaning console.')
-               subprocess.call(['stty', 'sane'])
+               self._restore_terminal_if_tty()

diff --git a/tools/testing/kunit/kunit_tool_test.py b/tools/testing/kunit/kunit_tool_test.py
index db4370032e97d0de9c6cb2901911595fa56035f0..267c33cecf8767cffe32ab06ef46a2aabb763b14 100755 (executable)
--- a/tools/testing/kunit/kunit_tool_test.py
+++ b/tools/testing/kunit/kunit_tool_test.py
@@ -529,6 +529,48 @@ class LinuxSourceTreeTest(unittest.TestCase):
                                self.assertIn('kunit.filter_glob=suite.test1', start_calls[0])
                                self.assertIn('kunit.filter_glob=suite.test2', start_calls[1])
 
+       def test_run_kernel_skips_terminal_reset_without_tty(self):
+               def fake_start(unused_args, unused_build_dir):
+                       return subprocess.Popen(['printf', 'KTAP version 1\n'],
+                                               text=True, stdout=subprocess.PIPE)
+
+               non_tty_stdin = mock.Mock()
+               non_tty_stdin.isatty.return_value = False
+
+               with tempfile.TemporaryDirectory('') as build_dir:
+                       tree = kunit_kernel.LinuxSourceTree(build_dir, kunitconfig_paths=[os.devnull])
+                       with mock.patch.object(tree._ops, 'start', side_effect=fake_start), \
+                            mock.patch.object(kunit_kernel.sys, 'stdin', non_tty_stdin), \
+                            mock.patch.object(kunit_kernel.subprocess, 'call') as mock_call:
+                               for _ in tree.run_kernel(build_dir=build_dir):
+                                       pass
+
+                               mock_call.assert_not_called()
+
+       def test_signal_handler_skips_terminal_reset_without_tty(self):
+               non_tty_stdin = mock.Mock()
+               non_tty_stdin.isatty.return_value = False
+               tree = kunit_kernel.LinuxSourceTree('', kunitconfig_paths=[os.devnull])
+
+               with mock.patch.object(kunit_kernel.sys, 'stdin', non_tty_stdin), \
+                    mock.patch.object(kunit_kernel.subprocess, 'call') as mock_call, \
+                    mock.patch.object(kunit_kernel.logging, 'error') as mock_error:
+                       tree.signal_handler(signal.SIGINT, None)
+                       mock_error.assert_called_once()
+                       mock_call.assert_not_called()
+
+       def test_signal_handler_resets_terminal_with_tty(self):
+               tty_stdin = mock.Mock()
+               tty_stdin.isatty.return_value = True
+               tree = kunit_kernel.LinuxSourceTree('', kunitconfig_paths=[os.devnull])
+
+               with mock.patch.object(kunit_kernel.sys, 'stdin', tty_stdin), \
+                    mock.patch.object(kunit_kernel.subprocess, 'call') as mock_call, \
+                    mock.patch.object(kunit_kernel.logging, 'error') as mock_error:
+                       tree.signal_handler(signal.SIGINT, None)
+                       mock_error.assert_called_once()
+                       mock_call.assert_called_once_with(['stty', 'sane'])
+
        def test_build_reconfig_no_config(self):
                with tempfile.TemporaryDirectory('') as build_dir:
                        with open(kunit_kernel.get_kunitconfig_path(build_dir), 'w') as f: