Use pytest-jupyter fixtures in unit testing

[mahendrapaipuri]

Proposed change

In a recent PR #396, unit testing is changed from running a external JupyterLab server to running the server via fixtures. This is already a good contribution as we do not need to run anything manually to do testing. The downside is that tests take way longer now as each test is spinning up a jupyter server (I guess?)

Aren't we supposed to use pytest-jupyter fixtures for this use cases? We have jp_fetch fixture which is what we need to test our cases. There is also sibling jp_ws_fetch for WS connection. We can use them "out-of-the-box" in the unit tests. I have tested them locally , they work fine and they are way faster. Is there any specific reason why these fixtures are not being used?

If not, I can put up a PR.

Who would use this feature?

Anyone who is contributing to the JSP project.