Code review comment for lp:~jameinel/bzr/2.3-filter-tests

Let's land this. The tests are worth having even when the bzrlib ExtendedTestResult class is fixed to print less junk on the console or subunit starts being pickier about what it does with success results.

A couple of notes. Thanks for the reasoning for _report_skip, makes it clear the method can probably be removed when the bzrlib/testtools boundary starts treating exceptions properly. The new tests that use testtools.TestResult rather than ExtendedTestResult check some things that would fail if the class switched because the behaviours are still quite different in a number of areas, but they should probably be converging anyway.