Approved file ordering wrong with SortedMaps

[JCook21]

I came across a use case recently where Approvals worked in a way that's different to what I expected. If you're using a sorted map implementation, such as a TreeMap, that sorts keys using something other than natural ordering the output of the approved file is not what is expected. It seems that StringUtils.toString(Map<?, ?> map) sorts maps by their keys by natural ordering. While this behaviour is consistent and the test will pass it's certainly not what you would expect when looking at the file (ask me how long I spent trying to work out why my TreeMap wasn't ordering things as expected before I worked out what was going on... ;) ). Would you consider adding support for sorted maps, maintaining their ordering?

[LarsEckart]

Yes, we'll look into this once we meet again. We're currently on a break though, busy times :)

[JCook21]

No worries, let me know if I can help when you do look into this.

[LarsEckart]

released as part of 15.0.0