diff --git a/pytest/__init__.py b/pytest/__init__.py
index 280549c0e..afc40b3f1 100644
--- a/pytest/__init__.py
+++ b/pytest/__init__.py
@@ -5,7 +5,7 @@ see http://pytest.org for documentation and details
 
 (c) Holger Krekel and others, 2004-2010
 """
-__version__ = '2.0.0.dev9'
+__version__ = '2.0.0.dev10'
 
 __all__ = ['config', 'cmdline']
 
diff --git a/setup.py b/setup.py
index c53444bcf..6c79bca6b 100644
--- a/setup.py
+++ b/setup.py
@@ -22,7 +22,7 @@ def main():
         name='pytest',
         description='py.test: simple powerful testing with Python',
         long_description = long_description,
-        version='2.0.0.dev9',
+        version='2.0.0.dev10',
         url='http://pytest.org',
         license='MIT license',
         platforms=['unix', 'linux', 'osx', 'cygwin', 'win32'],
diff --git a/testing/conftest.py b/testing/conftest.py
index ead6b5577..45c0d6eb2 100644
--- a/testing/conftest.py
+++ b/testing/conftest.py
@@ -7,9 +7,39 @@ collect_ignore = ['../build', '../doc/_build']
 rsyncdirs = ['conftest.py', '../pytest', '../doc', '.']
 
 import os, py
+pid = os.getpid()
+
+def pytest_addoption(parser):
+    parser.addoption('--lsof',
+           action="store_true", dest="lsof", default=False,
+           help=("run FD checks if lsof is available"))
+
+def pytest_configure(config):
+    if config.getvalue("lsof"):
+        try:
+            out = py.process.cmdexec("lsof -p %d" % pid)
+        except py.process.cmdexec.Error:
+            pass
+        else:
+            config._numfiles = getopenfiles(out)
+
+#def pytest_report_header():
+#    return "pid: %s" % os.getpid()
+
+def getopenfiles(out):
+    def isopen(line):
+        return ("REG" in line or "CHR" in line) and (
+            "deleted" not in line and 'mem' not in line)
+    return len([x for x in out.split("\n") if isopen(x)])
+
+def pytest_unconfigure(config, __multicall__):
+    if not hasattr(config, '_numfiles'):
+        return
+    __multicall__.execute()
+    out2 = py.process.cmdexec("lsof -p %d" % pid)
+    len2 = getopenfiles(out2)
+    assert len2 < config._numfiles + 7, out2
 
-def pytest_report_header():
-    return "pid: %s" % os.getpid()
 
 def pytest_generate_tests(metafunc):
     multi = getattr(metafunc.function, 'multi', None)