Improve the tests

[habedi]

• Add better tests, possibly using real-world dataset graphs (like https://huggingface.co/datasets/habedi/graphina-graphs)

[habedi]

Real-world graph fixtures are useful, but the test plan should first define which invariants each dataset exercises: disconnected components, multiedges, self-loops, weighted/negative edges, and large, sparse graphs. Keeping a few tiny graphs with hand-verifiable expected results beside one pinned external dataset would make failures diagnosable and avoid network-dependent tests. The external fixture should record its exact revision and license metadata in the repository.

I agree with you in principle. Right now, real-world graph datasets are mainly used to test (and benchmark) the upstream graph algorithm implementations in Graphina. It's not as systematic as you described it, but it helps find obvious bugs and prevent regressions. It also helps with benchmarking.

What you're describing reminds me of TinkerPop Modern Graph-style tests. I might use that approach, but at the moment, at least, I'm using NetworkX as a reference implementation to generate test fixtures (for differential testing). See these:

• https://github.com/habedi/graphina/tree/main/tests/oracle
• https://github.com/habedi/graphina/tree/main/scripts
• https://github.com/CogitatorTech/onager/blob/main/test/test_differential.py