Fix all default base IRIs of all test-cases

[TheMessik]

In some testcases, @base is not specified, yet the values are expected to be generated with respect to some base IRI.

This has been spotted in testcase 20a and testcase 22c.

[dachafra]

I don't think that test-cases are missing @base, indeed the behavior has changed because @base is for the actual turtle document and not for the triples generation, that's why we have introduced the rml:baseIRI. The error is the use of the default base IRI, which should be http://example/ and not http://example/base/.

[pmaria]

The error is the use of the default base IRI, which should be http://example/ and not http://example/base/.

This is not actually specified anywhere. In R2RML this was to be provided as input. In the R2RML test cases the base IRI used was http://example/base/.

The base IRI to be used should either be communicated with the test case, or we should decide if we want to introduce a default base IRI.

[dachafra]

I think @chrdebru has a clearer idea about this, as he run the test cases with BURP for the last challenge. @chrdebru is there any place where we have specified that the default base IRI is http://example/, or at least for the test cases, the base IRI used this one?

[chrdebru]

I can't find the pull requests, but some test cases relied on http://example.com/ instead of http://example.com/base/, and we changed that two years ago (challenge 2024), but it was never mentioned everywhere. The problem came from the fact that the mapping's base IRI was used in the expected output. In short, all test cases should mention the base IRI passed as a parameter.

I also suggest avoiding base IRI declarations in the mappings. Engines that rely on that "abuse" would then yield errors.

[bjdmeest]

We introduced rml:baseIRI as predicates for TriplesMaps to solve this issue, but I still think it's cleaner to specify a default base IRI if none is given. To avoid confusion, I would indeed refrain from specifying anywhere that the default base IRI can be derived from @base, and fix the test cases accordingly

[dachafra]

My suggestion then is:

1. Remove all @base from the mappings of the test cases
2. Add to the README.md file of each test case that the default base IRI used is http://example.com/