@xstate/test custom case name for description

[SimeonC]

I was running through some tests the other day and thought it might be useful to alter this section to support custom names instead of just JSON.stringify in the following code. In my example, I'm using an object with about 8 keys, but I have a unique name/id on each of them which would be easier to read the path.

Here's a screenshot of the output I have in cypress;

Proposed code change

https://github.com/davidkpiano/xstate/blob/326b28d25535c8ce1520258b80a119f26847951b/packages/xstate-test/src/index.ts#L137-L145

type formatCase = (event: EventObject) => string;

function formatEvent(event: EventObject): string {
  const { type, ...other } = event;

  let propertyString = '';
  if (Object.keys(other).length) {
    if (this.options.events[type].formatCase) {
      propertyString = ` ${this.options.events[type].formatCase(event)}`;
    } else {
      propertyString = ` (${JSON.stringify(other)})`;
    }
  }

  return `${type}${propertyString}`;
}

If this is something that other people would find useful in the code I'd be happy to make an MR for it (if/when I get the time). At present, it's just a minor annoyance and so far the only one I've found 😁

EDIT: This gets even worse if you start passing in arrays inside the cases - I have over two screens worth of JSON text for one test 😂