It seems AbstractStringInstanceIdentifierCodec is not handling values correctly, as it uses String.valueOf() on the object – bypassing any additional processing – so, for example, I do not believe in handles identityref and instance-identifier references correctly.

Furthermore it does not perform any escaping, which probably means we cannot handle strings containing backslashes, or single quotes or double quotes.

This relates to YANGTOOLS-1361, as it provides a counterpart parser, which needs to behave correctly w.r.t. these.

Write a set of tests to show how we handle these corner cases.