tests: subprocess.communicate block on Python 2.7

https://github.com/eventlet/eventlet/pull/24
+ PEP8 fix tabs

tests/subprocess_test.py

@@ -1,6 +1,7 @@
 import eventlet
 from eventlet.green import subprocess
 import eventlet.patcher
+from nose.plugins.skip import SkipTest
 import os
 import sys
 import time
@@ -12,8 +13,8 @@ def test_subprocess_wait():
     # In Python 3.3 subprocess.Popen.wait() method acquired `timeout`
     # argument.
     # RHEL backported it to their Python 2.6 package.
-	p = subprocess.Popen([sys.executable,
+    p = subprocess.Popen(
-	                     "-c", "import time; time.sleep(0.5)"])
+        [sys.executable, "-c", "import time; time.sleep(0.5)"])
     ok = False
     t1 = time.time()
     try:
@@ -23,3 +24,22 @@ def test_subprocess_wait():
     tdiff = time.time() - t1
     assert ok == True, 'did not raise subprocess.TimeoutExpired'
     assert 0.1 <= tdiff <= 0.2, 'did not stop within allowed time'
+
+
+def test_communicate_with_poll():
+    # https://github.com/eventlet/eventlet/pull/24
+    # `eventlet.green.subprocess.Popen.communicate()` was broken
+    # in Python 2.7 because the usage of the `select` module was moved from
+    # `_communicate` into two other methods `_communicate_with_select`
+    # and `_communicate_with_poll`. Link to 2.7's implementation:
+    # http://hg.python.org/cpython/file/2145593d108d/Lib/subprocess.py#l1255
+    if getattr(original_subprocess.Popen, '_communicate_with_poll', None) is None:
+        raise SkipTest('original subprocess.Popen does not have _communicate_with_poll')
+
+    p = subprocess.Popen(
+        [sys.executable, '-c', 'import time; time.sleep(0.5)'],
+        stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    t1 = time.time()
+    eventlet.with_timeout(0.1, p.communicate, timeout_value=True)
+    tdiff = time.time() - t1
+    assert 0.1 <= tdiff <= 0.2, 'did not stop within allowed time'