Subunit and subtests

Python 3 recently introduced a nice feature – subtests. When I was putting subunit version 2 together I tried to cater for this via a heuristic approach – permitting the already known requirement that some tests which are reported are not runnable be combined with substring matching to identify subtests.

However that has panned out poorly, when I went to integrate this with testr the code started to get fugly.

So, I’m going to extend the StreamResult API to know about subtests, and issue a subunit protocol bump – to 2.1 – to add a new field for labelling subtest events. My plan is to make this build a recursive tree structure – that is given test “test_foo” with subtest “i=3” which the Python subtest code would identify as “test_foo (i=3)”, they should be identified in StreamResult as test_id “test_foo (i=3)” and parent_test_id “test_foo”. This can then nest arbitrarily deep if test runners decide to do that, and the individual runnability becomes up to the test runner, not testrepository / subunit / StreamResult.