Storyshots: Fix typings of "test"-method

[nknapp]

Issue: #12361

What I did

Adjust the typescript definition of storyshot's "test" method to better reflect reality.
It could be improved, but I am not sure which args are really passed all the time
(or maybe only depending on the framework).

How to test

• Is this testable with Jest or Chromatic screenshots? no
• Does this need a new example in the kitchen sink apps? no
• Does this need an update to the documentation? maybe

If your answer is yes to any of these, please make sure to include it in your PR.

[shilman]

Thanks for digging into this! I'm not too familiar with this code, but it seems like more changes are needed, e.g.

https://github.com/storybookjs/storybook/blob/next/addons/storyshots/storyshots-core/src/test-bodies.ts#L15-L20

Any chance you can do a more thorough audit of the code to tighten things up as part of this change?

[nknapp]

Let's see how it works now. I have done the following changes:

• fix the TestMethodOptions based on the types found in test-bodies (use a union of all arg-types of all methods defined there).
• refactor the test-bodies to use the new StoryshotsTestMethod. I was a bit confused at first, about what the functions are doing, and I hope that my change makes it clear that they are actually returning test-methods.

Both changes are in separate commits, you can pick either

[nknapp]

@shilman I have made some changes and they are ready for review. I am not sure if I have to do anything to change the state of this PR so that it gets your attention again. It is still in "Changes requested" state.

[shilman]

@nknapp i'm on it 😄

[shilman]

LGTM!