SPARQL query fuzzing

[rubensworks]

Issue type:

• ➕ Feature request

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Description:

In order to make our query parsing and execution more stable, we should add a fuzzing testing to CI (or through some external service).
Concretely, we should generate random queries (probably deterministically), issue them to Comunica, and either expect valid responses or a sane error message.

AFAIK, no software exists yet for SPARQL fuzzing, so we'd have to create something ourselves.

Related to #167

[github-actions]

Thanks for the suggestion!