Testing suggestions

[jeswr]

It would be good to have TPF and QPF endpoint testing for characteristics such as:

• The engine only collects the necessary pages (doesn't try and get default graphs if there are none, doesn't paginate too far, etc.)
• The engine collects the correct data (doesn't put triples from a QPF endpoint without a default graph into the default graph)
• The metadata is accurate (when I was snooping on metadata for something else it looked like there was a metadata result indicating the first all page contained the same number of triples as the full dataset size)

Originally raised in comunica/comunica#1151 (comment)