Here is a patch to the tests that allows the tests to pass when the install path is long while still checking that file names show up correctly in the traceback.

One advantage of this patch's approach is that it provides a way to test the rendering of long paths on all systems/installs.  Simply create a test case by setting the scriptname to, for example--

scriptname = 'test_long_file_path_' + 200 * 'x'

This patch is just an illustration for discussion purposes and is not meant as a final patch.

Also, this patch does not fix the issue of the file names of long paths not getting rendered (which can be addressed by setting the limit to 500 as we discussed).  However, as I have noted this patch provides a way to test such a fix.