test: proposal common.expectsError nextTick option

[ronag]

I would like to propose a new option for common.expectsError which will indicate whether the error can be invoked in the same tick or not, e.g.

I would like to be able to replace tests like this:

let ticked = false;
stream.write(null, common.mustCall((err) => {
 assert.strictEqual(ticked, true);
 common.expectsError(opts)(err);
}));
ticked = true;

with

stream.write(null, common.expectsError({
 ...opts,
 nextTick: true
});

Would this make sense? It's quite often that one wants to test for callback errors and that they should be invoked asynchronously.

I think this would also help us actually making sure that callbacks are invoked asynchronously.

NOTE: Can I use expectsError to test for no error?

[Trott]

I (probably) wouldn't block it, but I think the first example is clear. I think the proposed API results in code where it is not immediately obvious what is going on. So someone will have to go and read the documentation, which increases friction.

If anything, in the first example, I might avoid common.expectsError() and use one or more calls to assert.strictEqual() instead. The test code will be longer, but it will be clearer. No one will have to learn our common.expectsError() function to understand the test.

[cjihrig]

I share @Trott's opinion on this issue.

I'd actually like to see common.expectsError() go away completely, but that's not the topic of this issue 😄

[ronag]

Makes sense.