Show test suite file names in failure output

[kumar303]

Describe the problem and steps to reproduce it:

Trigger a test failure that happens on the event loop. In other words, one that won't produce a stack trace pointing back to the test file.

What happened?

You have no easy way to figure out which test file produced the error. Example:

What did you expect to happen?

You should be able to easily figure out which test file produced the error.

Anything else we should know?

We can totally do this now that Jest runs from NodeJS! We can start every test with describe(__filename, ...) which will produce errors like this:

[kumar303]

Hah, ignore me. I have so much console output (thinking of jestjs/jest#4156) that I forgot how Jest prints the failing test name at the top:

[tofumatt]

That's what I thought happened but figured maybe with a catastrophic failure it wouldn't print.

Nothing to see here then! 😅

[kumar303]

I thought about this more and I still think the change would be helpful. What do you think? Here are the benefits I see:

• The bottom line of a failing test will always show the filename. Otherwise, you'd have to scroll up beyond all the console logging to find it.
• We won't have to think of what to type in the initial describe() function ever again :) It can just always be __filename

[tofumatt]

I'm okay with all root-level describe()s amounting to describe(__filename) but I'd rather there just be a helper–that sort of boilerplate is annoying...

Dunno if that's possible though. I'm cool with this idea regardless though, I can never think of what to name these things!

[kumar303]

I don't think a helper would be helpful because you'd have to pass it __filename since that is different depending on the file. In other words, a helper would have to look like:

describe(showFile(__filename), ...);

which is pointless.

[tofumatt]

Oh shoot, duh, right. I didn’t think that one through 😓