add aggregation tests which involve unbound variables

[lisp]

two tests have been proposed to demonstrate permitted aggregation results in the presence of unbound variables.

it would be worthwhile, in addition, to include tests which distinguish results where an implementation suppresses unbound values where permitted.

• one test which fails if the respective sample result is unbound. this should be associated with a new feature, to document which of the alternative behaviours an implementation follows.
• one test which requires that an unbound value be valid as a group key. i did not see this yet covered, but may have overlooked a test which already does.

[gkellogg]

It's probably useful to surface this on [email protected] and [email protected], as not everyone interested in this subscribes to the GitHub issues feed.

[gkellogg]

🎱 As I see has been done: https://lists.w3.org/Archives/Public/public-sparql-dev/2016JanMar/0010.html

[gkellogg]

A PR with proposed tests and results would be welcome.

[lisp]

yes, this is a follow-on to that post.

before proposing tests, it would be good to have some degree of consensus concerning the content:

• whould it be appropriate to a feature?
• if so, what it might be named? would it be 'mf' or 'sd'?
• should it be reflected in the service description?

[joernhees]

just linking this more directly: kasei@389617a @kasei

[gkellogg]

@lisp, perhaps a conversation referencing this thread, on [email protected] and [email protected] might spur more discussion.