Reimplement ubuntutools.subprocess.Popen as a class instead of a factory function.

ubuntutools/subprocess.py

@@ -21,7 +21,8 @@ from subprocess import PIPE, STDOUT, CalledProcessError
 __all__ = ['Popen', 'call', 'check_call', 'check_output', 'CalledProcessError', 'PIPE', 'STDOUT']
 
 
-def Popen(*args, **kwargs):
+class Popen(subprocess.Popen):
+    def __init__(self, *args, **kwargs):
         kwargs.setdefault('close_fds', True)
 
         if 'restore_signals' not in inspect.getargspec(subprocess.Popen.__init__)[0]:
@@ -38,7 +39,7 @@ def Popen(*args, **kwargs):
                     given_preexec_fn()
             kwargs['preexec_fn'] = preexec_fn
 
-    return subprocess.Popen(*args, **kwargs)
+        subprocess.Popen.__init__(self, *args, **kwargs)
 
 
 # call, check_call, and check_output are copied directly from the

ubuntutools/test/test_pylint.py

@@ -28,8 +28,8 @@ WHITELIST = [re.compile(': %s$' % x) for x in (
     # mox:
     r"Instance of '.+' has no '(WithSideEffects|MultipleTimes|AndReturn)' "
     r"member",
-    # Wrong Popen
-    r"Function 'Popen' has no '__init__' member",
+    # pylint doesn't like *args/**kwargs
+    r"Instance of 'Popen' has no '.*' member",
 )]
 
 class PylintTestCase(unittest.TestCase):