SPARQLStore graph awareness

[bcogrel]

Here is a proposal for making SPARQLStore and SPARQLUpdateStore be graph_aware (see issue #399).

Two new methods add_graph and remove_graph have been added to these classes. They raise a read-only error when simple SPARQLStore are used. The SPARQLUpdateStore uses the CREATE and DROP SPARQL commands.

The default graph of the Dataset is the default graph of the SPARQL endpoint.

To test it, I have adapted test_dataset. However, the SPARQL endpoint configuration it requires is in conflict with test_sparqlupdatestore. Indeed the latter wants an union default graph (like tdb:unionDefaultGraph) that may cause the default graph to be read-only while the former tests the "non union" and writes into the default graph. Any suggestion? Should we execute these tests manually one by one? Remind that tests are skipped if no endpoint is available.

Please note that commits of #401 have also been included in this patch.

[gromgull]

Thanks a lot!

As you say - the tests are anyway not run automatically, and will have to be run by people who have setup fuseki or similar. I think your printed warnings are good enough!

[bcogrel]

Great! Happy to hear that :)