Add tests for frontend

[igoradamenko]

After adding mocks in #86 it's important to cover frontend by E2E-tests.

You are welcome to start this journey with a little PR which configures env for testing and adds some examples of them.

[igoradamenko]

Thanks @Mavrin for testing env which he set up in #100. Right now we need to cover our UI by tests.

I think we need to start from adding mocks (#86), then add some coverage counting tool (if it's possible for this tasks), and then write tests and try to cover the biggest part :-)

[slawiko]

@igoradamenko don't forget about #96 . Smaller components easier to test. I propose to first split huge components on atomic parts and then add testing.

[umputun]

@Reeywhaar - was it addressed as a part of your massive refactoring? Can you take a look at issues like this one and update? I'm trying to prepare a new release and want to attach the list of tickets we have addressed

[Reeywhaar]

This is is indeed stale, it's tricky to write frontend tests properly, and no one bothers, including me. Though there is a lot of issues that were fixed long ago.

[akellbl4]

I think this issue not actual for now.
We have env for testing and some test, also we write tests for new features and write test in places what we change.

[paskal]

That was added in #1464.