feat: Switch from nosetest to pytest (#10177)

* Switch from nosetest to pytest

Fix schedule tests

Collect pytest coverage

Move pytest config into pytest.ini

Move cov to the pytest.ini

* Append coverage for the 2nd run

* Add coverage to all commands

* Coverage only for tests

* Get coverage from 1 place

* Rename classes to be  pytest compatible

* Test coverage for examples and tests

* Max diff to -1

* Explain how to run pytest for the whole project

* Do not append code coverage for the main run

* Do not run coverage on examples

Co-authored-by: bogdan kyryliuk <bogdankyryliuk@dropbox.com>

tests/stats_logger_tests.py

@@ -21,7 +21,7 @@ from unittest.mock import Mock, patch
 from superset.stats_logger import StatsdStatsLogger
 
 
-class StatsdStatsLoggerTest(TestCase):
+class TestStatsdStatsLogger(TestCase):
     def verify_client_calls(self, logger, client):
         logger.incr("foo1")
         client.incr.assert_called_once()