twister: check if output is connected to tty before 'stty sane' call

As of today we unconditionally call 'stty sane' that leads to
lots of error messages
'stty: standard input: Inappropriate ioctl for device'
when output isn't connected to tty (for example when we launch
twister in Jenkins)

Fix that by check if output is really connected to tty before
'stty sane' call.

Signed-off-by: Eugeniy Paltsev <[email protected]>

Author: Eugeniy Paltsev

scripts/pylib/twister/twisterlib.py

@@ -564,8 +564,9 @@ def handle(self):
 
         # FIXME: This is needed when killing the simulator, the console is
         # garbled and needs to be reset. Did not find a better way to do that.
+        if sys.stdout.isatty():
+            subprocess.call(["stty", "sane"])
 
-        subprocess.call(["stty", "sane"])
         self.instance.results = harness.tests
 
         if not self.terminated and self.returncode != 0:
@@ -1063,7 +1064,8 @@ def handle(self):
         self.thread.daemon = True
         logger.debug("Spawning QEMUHandler Thread for %s" % self.name)
         self.thread.start()
-        subprocess.call(["stty", "sane"])
+        if sys.stdout.isatty():
+            subprocess.call(["stty", "sane"])
 
         logger.debug("Running %s (%s)" % (self.name, self.type_str))
         command = [self.generator_cmd]