Revert "Use signal.alarm() for py2 timeout"

This reverts commit 900cef6397.

src/_pytest/pytester.py

@@ -2,13 +2,11 @@
 from __future__ import absolute_import, division, print_function
 
 import codecs
-import contextlib
 import gc
 import os
 import platform
 import re
 import subprocess
-import signal
 import six
 import sys
 import time
@@ -1085,21 +1083,6 @@ class Testdir(object):
                 popen.wait()
                 raise self.TimeoutExpired(timeout_message)
 
-            @contextlib.contextmanager
-            def timeout_manager(handler, timeout):
-                original_handler = signal.getsignal(signal.SIGALRM)
-                if original_handler != signal.SIG_DFL:
-                    # TODO: use an informative exception
-                    raise Exception()
-
-                signal.signal(signal.SIGALRM, handler)
-                signal.alarm(timeout)
-
-                yield
-
-                signal.alarm(0)
-                signal.signal(signal.SIGALRM, original_handler)
-
             if timeout is None:
                 ret = popen.wait()
             elif six.PY3:
@@ -1108,10 +1091,20 @@ class Testdir(object):
                 except subprocess.TimeoutExpired:
                     handle_timeout()
             else:
-                with timeout_manager(
+                end = time.time() + timeout
-                    handler=lambda _1, _2: handle_timeout(), timeout=timeout
+
-                ):
+                resolution = min(0.1, timeout / 10)
-                    ret = popen.wait()
+
+                while True:
+                    ret = popen.poll()
+                    if ret is not None:
+                        break
+
+                    remaining = end - time.time()
+                    if remaining <= 0:
+                        handle_timeout()
+
+                    time.sleep(resolution)
         finally:
             f1.close()
             f2.close()