Test case missing for Triples Map without Logical Source

[jduchateau]

A test case is missing for a Triples Map without a Logical Source.

From the specs:

Note
The logical source on a triples map can be omitted if all its term maps produce values irrespective of a logical source. This is the case if all its term maps are constant-valued expression maps, or have rml:BlankNode as term type and no declared expression.