Fixes #1429, add iri2uri

[ghost]

Fixes #1429

#1429 (comment))

why park this in the "restore-pyrdfa" branch? This fix will work for non-HTML sources with non-ASCII chars in the IRI, perhaps something like http://example.com/thing/Almería.ttl for instance. So this is a generic fix for parse()

Summary of changes

Add an iri-to-uri conversion utility to encode IRIs to URIs for Graph.parse() sources. Added a couple of tests because feeding it with a suite of IRIs to check seems overkill (not that I could find one).

Checklist

• Checked that there aren't other open pull requests for the same change.
• Added tests for any changes that have a runtime impact.
• Checked that all tests and type checking passes.
• For changes that have a potential impact on users of this project:
  • Updated relevant documentation to avoid inaccuracies.
  • Considered adding additional documentation.
  • Considered adding an example in ./examples for new features.
  • Considered updating our changelog (CHANGELOG.md).
• Considered granting push permissions to the PR branch,
  so maintainers can fix minor issues and keep your PR up to date.

[coveralls]

Coverage increased (+0.009%) to 88.431% when pulling 72f5b59 on gjhiggins:fix-for-issue1429 into ccb9c4a on RDFLib:master.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[aucampia]

Made some changes now to your branch, in brief:

• Move rdflib.parser.iri2uri to rdflib.util._iri2uri

  In part this is because iri2uri does not operate on all IRIs, just
  http and https IRIs, but furthermore it is because this is not
  something essential to working with RDF.

• Expanded tests for iri2uri to cover each part of the URI.

• Convert the test that connects to dbpedia to using httpmock.

  This is so we have more control over response and can explicitly
  verify the request path.

• Some changes to imports to reduce the probability of circular imports.

[aucampia]

LGTM

[edmondchuc]

Nice! Looks good.