Unit Tests RDF Serialisation

[robons]

Serialisation of our RDF models can be triggered by creating an rdflib.Graph and passing it to the model.to_graph(...) method on the model.

graph = rdflib.Graph()
model.to_graph(graph)
# you can now query `graph` as you would any RDF datastore.

• Add Unit-test framework to sharedmodel package.
• Test overriding of attributes in subclass - do we see the overriden triple outputted whilst the original triple is suppressed?
• Test that Resource[T] is serialised properly for both ExistingResource and NewResource types (ensures recursive serialisation for NewResource types).
• Test that circular Resource[T] references are serialised properly.
• Test that multiple Triples can be specified in an annotation. Ensure they both get serialised properly.
• Test exceptions are raised when PropertyStatus.mandatory triples have no value provided when serializing, but recommended/optional silently pass where values haven't been provided.

[rossbowen]

model above refers to any subclass of sharedmodels.rdf.resource.RdfResource. Any subclass of RdfResource can be serialised into RDF.

https://github.com/GSS-Cogs/csvwlib/blob/ded06aac145c9ab55a470b5da89dadc307be7a37/sharedmodels/sharedmodels/rdf/resource.py#L13

This is used when writing to CSVW - RDF-like classes are serialised into RDF and then output into JSON-LD.

https://github.com/GSS-Cogs/csvwlib/blob/ded06aac145c9ab55a470b5da89dadc307be7a37/csvqb/csvqb/writers/qbwriter.py#L33

https://github.com/GSS-Cogs/csvwlib/blob/ded06aac145c9ab55a470b5da89dadc307be7a37/csvqb/csvqb/writers/qbwriter.py#L89-L95