Previously the test-bots script filtered out base-class tests from
BotTestCase. With this change, BotTestCase continues to inherit from
unittest.TestCase, but the default test_* methods previously in this
class are now in a new DefaultTests class, which does not. Instead, each
bot needs to inherit from BotTestCase and DefaultTests *explicitly*.
This avoids the need to filter out the base-class tests, which
simplifies the test-bots script, and may ease any migration to eg.
pytest.
The DefaultTests class does require some non-implemented methods which
BotTestCase provides.
This commit was originally from @fredfishgames, but it
needed a big rebase due to use letting it sit too long.
Also, we decided not to have shebangs at the top of test
files.
doc.md better describes the style of documentation that will live
inside these files, since we want these to be similar to our
webhooks' doc.md files in terms of how these are rendered and
composed of Markdown macros.
