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/email_tests.py

@@ -34,7 +34,7 @@ send_email_test = mock.Mock()
 logger = logging.getLogger(__name__)
 
 
-class EmailSmtpTest(SupersetTestCase):
+class TestEmailSmtp(SupersetTestCase):
     def setUp(self):
         app.config["smtp_ssl"] = False