some test fixes and configure tox-testing against pytest==2.3.5 and pytest>=2.4.2

xdist/__init__.py

@@ -1,2 +1,2 @@
 #
-__version__ = '1.9dev2'
+__version__ = '1.9'

xdist/dsession.py

@@ -177,13 +177,13 @@ def report_collection_diff(from_collection, to_collection, from_id, to_id):
         fromfile=from_id,
         tofile=to_id,
     )
-    error_message = (
-        u'Different tests were collected between {from_id} and {to_id}. '
-        u'The difference is:\n'
-        u'{diff}'
+    error_message = py.builtin._totext(
+        'Different tests were collected between {from_id} and {to_id}. '
+        'The difference is:\n'
+        '{diff}'
     ).format(from_id=from_id, to_id=to_id, diff='\n'.join(diff))
-
-    raise AssertionError(error_message)
+    msg = "\n".join([x.rstrip() for x in error_message.split("\n")])
+    raise AssertionError(msg)
 
 
 class Interrupted(KeyboardInterrupt):

xdist/remote.py

@@ -128,7 +128,7 @@ if __name__ == '__channelexec__':
     # python3.2 is not concurrent import safe, so let's play it safe
     # https://bitbucket.org/hpk42/pytest/issue/347/pytest-xdist-and-python-32
     if sys.version_info[:2] == (3,2):
-        os.environ["PYTHONDONTWRITEBYTECODE"] = 1
+        os.environ["PYTHONDONTWRITEBYTECODE"] = "1"
     slaveinput,args,option_dict = channel.receive()
     importpath = os.getcwd()
     sys.path.insert(0, importpath) # XXX only for remote situations