Questions about outwin.py:

1. Should a main() be added for htest and unittest?

2. In _file_line_helper, to test if the file exists, the file is opened, then closed.  Would os.path.isfile work here?

Questions about tests:
1. OutputWindow is an EditorWindow and EditorWindow has a superclass of Object.  I didn't know how to make tests to test the text binding for goto-file-line.  Or how to test the other functions.  I tried emulating the dialogs, but couldn't get it to work.  Is there any existing test for another module I can study and copy?  EditorWindow didn't really have any tests for this yet, but if I learn how to do it here, I can apply it there.

2. The `goto_line_file` function compiles the class attribute for the matching patterns `file_line_pats` which is then used by `_file_line_helper`.  I had trouble writing a test just for the helper without copying this pattern compile code from the other function.  I wasn't sure how to get around that.  Are the patterns at the class level so that they are cahced for all the calls?  How should I change the test?  Can the patterns be compiled inside `_file_line_helper`?

3.  Is the test of `_file_line_helper` the right way to go with the tests?  Should examples of each pattern be included?  I didn't add a test for the TypeError because the pattens didn't seem like they would match on anything but digits.  Should I add a pattern for testing just for code coverage?

Thanks!