Custom message not always respected

[meeber]

As noted here, there's a problem with some assertions not always respecting a custom failed assertion error message. This problem is different (and more widespread) than the flag transfer problem mentioned in #904.

Here's an example:

expect('blah').to.be.closeTo(2, 1, 'CUSTOM');  // Correctly includes custom error message
expect('blah', 'CUSTOM').to.be.closeTo(2, 1); // Incorrectly excludes custom error message

The culprit for the above example is this line. If the msg argument isn't provided, then it needs to look at the value of the msg flag instead.

Many other occurrences of this issue are similar to the above example. Also there are some assertions that fail to pass on the msg at all to internal assertions or errors, but #922 coincidentally fixes those occurrences.

[keithamus]

Something I'd like to just throw out there: is it worth fixing these issues given that if we implement #585 anything like it currently looks, then messaging will be centralised and automated, and any efforts will be refactored away?

[meeber]

I think it's worth it, it's a quick-n-easy fix, low-impact. Just waiting for #922 so don't have to mess with resolving merge conflicts.