More explicit error message

subprocess2.py

Index: subprocess2.py
diff --git a/subprocess2.py b/subprocess2.py
index 716ef20faed48ffc9866e5da77a5207927bf857d..48a367151f0daabe916f26cba5d098ea2882ea0f 100644
--- a/subprocess2.py
+++ b/subprocess2.py
@@ -248,8 +248,9 @@ class Popen(subprocess.Popen):
             'to learn how to fix this error; you need to rebase your cygwin '
             'dlls')
       # Popen() can throw OSError when cwd or args[0] doesn't exist.
-      raise OSError('%s or %s probably doesn\'t exist' %
-                    (kwargs.get('cwd'), args[0]))
+      raise OSError(('Execution failed with error: %s. '

[Ryan Tseng, 2014/04/21 21:50:29]

nit: a \n at the end here would probably be good.
Also the inner parens aren't necessary.
('foo '
 'baz'
 % bar)
will work.

+                     'Check that %s or %s exist and have execution permission.'
+                     ) % (str(e), kwargs.get('cwd'), args[0]))
 
   def _tee_threads(self, input):  # pylint: disable=W0622
     """Does I/O for a process's pipes using threads.