1 files changed, 53 insertions, 0 deletions
diff --git a/cros_utils/no_pseudo_terminal_test.py b/cros_utils/no_pseudo_terminal_test.py
new file mode 100644
index 00000000..43eabb13
--- /dev/null
+++ b/cros_utils/no_pseudo_terminal_test.py
@@ -0,0 +1,53 @@
+"""Test to ensure we're not touching /dev/ptmx when running commands."""
+
+from __future__ import print_function
+
+import os
+import subprocess
+import tempfile
+import time
+import unittest
+from cros_utils import command_executer
+
+
+class NoPsuedoTerminalTest(unittest.TestCase):
+  """Test to ensure we're not touching /dev/ptmx when running commands."""
+
+  _strace_process = None
+  STRACE_TIMEOUT = 10
+
+  def _AttachStraceToSelf(self, output_file):
+    """Attaches strace to the current process."""
+    args = ['strace', '-o', output_file, '-p', str(os.getpid())]
+    print(args)
+    self._strace_process = subprocess.Popen(args)
+    # Wait until we see some activity.
+    start_time = time.time()
+    while time.time() - start_time < self.STRACE_TIMEOUT:
+      if os.path.isfile(output_file) and open(output_file).read(1):
+        return True
+      time.sleep(1)
+    return False
+
+  def _KillStraceProcess(self):
+    """Kills strace that was started by _AttachStraceToSelf()."""
+    self._strace_process.terminate()
+    self._strace_process.wait()
+    return True
+
+  def testNoPseudoTerminalWhenRunningCommand(self):
+    """Test to make sure we're not touching /dev/ptmx when running commands."""
+    temp_file = tempfile.mktemp()
+    self.assertTrue(self._AttachStraceToSelf(temp_file))
+
+    ce = command_executer.GetCommandExecuter()
+    ce.RunCommand('echo')
+
+    self.assertTrue(self._KillStraceProcess())
+
+    strace_contents = open(temp_file).read()
+    self.assertFalse('/dev/ptmx' in strace_contents)
+
+
+if __name__ == '__main__':
+  unittest.main()