Issue with pytest and it's plugins dependencies

[naved001]

We are using pytest version < 3.6 because of an issue described here fd68983

The latest version of two pytest plugins (pytest-cov and pytest-xdist) require a more recent version of pytest.

We should update our tests with features recommended by pytest, and use the latest version of pytest and it's plugins.

[naved001]

I started working on this: master...naved001:remove-direct-fixture-calls

There's more work to do.