>>> x = shlex.split("TEST_PATH=content/base/test/test_CrossSiteXHR.html make -C obj-ff-dbg mochitest-plain")
>>> x
['TEST_PATH=content/base/test/test_CrossSiteXHR.html', 'make', '-C', 'obj-ff-dbg', 'mochitest-plain']
>>> subprocess.call(x)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/subprocess.py", line 470, in call
    return Popen(*popenargs, **kwargs).wait()
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/subprocess.py", line 623, in __init__
    errread, errwrite)
  File "/opt/local/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/subprocess.py", line 1141, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory