Summary: Test a subset of tests

Description:
This module allows to run a subset of the 'subtest' tests given in a test
file.

The module declaration takes a whitelist of the subtests we want to run.
Any subtest that doesn't match any of the whitelist items will be skipped
(or potentially bypassed).

The test files don't even need to be modified, as the module can also be
invoked from the command-line. E.g.,

Maintainer: nobody