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>

tox.ini

@@ -18,8 +18,10 @@
 commands =
     {toxinidir}/superset/bin/superset db upgrade
     {toxinidir}/superset/bin/superset init
-    nosetests tests/load_examples_test.py
-    nosetests --exclude=load_examples_test {posargs:tests}
+    pytest -ra -q tests/load_examples_test.py
+    # use -s to be able to use break pointers.
+    # no args or tests/* can be passed as an argument to run all tests
+    pytest --ignore=load_examples_test {posargs}
 deps =
     -rrequirements.txt
     -rrequirements-dev.txt