Terry,

In test_browser, would it be a good test if mock_pyclbr_tree was created as 
`mock_pyclbr_tree = {'C0': C0, 'f0': f0}` 
instead of 
`mock_pyclbr_tree = {'f0': f0, 'C0': C0}`?

The reason that I'm asking is that, under 2.7 and 3.3, this dictionary does not retain the insertion order, but changes it from (C0, f0) to (f0, C0).  

Or did you just want a test that checks that the line numbers are still in order when the code is returned from transform_children?