diff --git a/src/OpenSSL/tsafe.py b/src/OpenSSL/tsafe.py
index ba17d73..1cc0d2b 100644
--- a/src/OpenSSL/tsafe.py
+++ b/src/OpenSSL/tsafe.py
@@ -1,10 +1,6 @@
-from OpenSSL import SSL
-_ssl = SSL
-del SSL
+from threading import RLock as _RLock
 
-import threading
-_RLock = threading.RLock
-del threading
+from OpenSSL import SSL as _ssl
 
 
 class Connection:
diff --git a/tests/memdbg.py b/tests/memdbg.py
index 0deeb9e..e927332 100644
--- a/tests/memdbg.py
+++ b/tests/memdbg.py
@@ -1,11 +1,16 @@
 import sys
-sys.modules['ssl'] = None
-sys.modules['_hashlib'] = None
-
 
 import traceback
 
 from cffi import api as _api
+
+
+assert sys.modules.get('ssl') is None
+assert sys.modules.get('_hashlib') is None
+sys.modules['ssl'] = None
+sys.modules['_hashlib'] = None
+
+
 _ffi = _api.FFI()
 _ffi.cdef(
     """
diff --git a/tests/runtests.py b/tests/runtests.py
deleted file mode 100644
index aca1d61..0000000
--- a/tests/runtests.py
+++ /dev/null
@@ -1,17 +0,0 @@
-"""
-This is a legacy file that no-one currently knows how to use.
-
-Please run your tests using ``py.test tests`` or ``tox``.
-"""
-
-import sys
-sys.modules['ssl'] = None
-sys.modules['_hashlib'] = None
-
-try:
-    from . import memdbg  # noqa
-except Exception as e:
-    pass
-
-from twisted.scripts.trial import run
-run()