This patch replace all uses of nose with pytest. It also includes a
pytest plugin for creating EARL reports for tests with a `rdf_test_uri`
parameter.
Some caveats:
- HTML report directory is now htmlcov instead of coverage
- There is some warning related to the EARL reporting plugin which I can't quite figure out:
```
.venv/lib64/python3.7/site-packages/_pytest/config/__init__.py:676
/home/iwana/sw/d/github.com/iafork/rdflib/.venv/lib64/python3.7/site-packages/_pytest/config/__init__.py:676: PytestAssertRewriteWarning: Module already imported so cannot be rewritten: test.earl
self.import_plugin(import_spec)
```
This is not causing any problems as far as I can tell, but still annoying.
- python setup.py test won't work anymore, I can make it work but this
is not advised by pytest:
https://github.com/pytest-dev/pytest-runner/#deprecation-notice
- run_test.py is still there but it's not really referenced anymore from
anywhere and the options it accepts are completely different as it's options
were based on nose. I would say it should be removed entirely but for now
it is basically just a wrapper around pytest that basically does nothing.
- Removed references to test attributes as currently they are not being
used anywhere anyway, I guess we can add them back if there is some
use for them later.
- A lot of tests are still marked to skip when really they should be marked
with xfail. This is also affecting the RDFT test manifests and result in
reports saying tests are skipped when really we know they will fail and
they are only skipped for this reason. But there is no change here from
before, and pytest makes it easier to dynamically do expected failures.
Special thanks to Wes Turner for his advice and inputs on this process.