feat: Astra - improve filters and add unit tests

[anakin87]

Related Issues

• fixes Astra document store filter tests are skipped #869
• part of https://github.com/deepset-ai/haystack-private/issues/275

Proposed Changes:

• implement better filters, more aligned with Haystack defaults
• add unit tests for Astra, focusing on uncovered code paths (with some AI help)
• simplify/parametrize some existing tests

How did you test it?

CI

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test:.

[github-actions]

Coverage report (astra)

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
integrations/astra/src/haystack_integrations/components/retrievers/astra
retriever.py
integrations/astra/src/haystack_integrations/document_stores/astra
astra_client.py
document_store.py
filters.py					68, 70, 74, 86-87, 108-109, 128, 130-134, 139, 146, 153, 160, 174-175
Project Total

This report was generated by python-coverage-comment-action

[bogdankostic]

Looking good in principle, I was just wondering if we could remove the overwrites of the filter tests below this line, given that filters seem to be supported looking at test_filters_unit.py.

[anakin87]

Looking good in principle, I was just wondering if we could remove the overwrites of the filter tests below this line, given that filters seem to be supported looking at test_filters_unit.py.

Prompted by this comment, I decided to investigate better.

And I realized that we could not remove overwrites right away. So I decided to implement better filters for Astra (with some help from AI) and now filters are more aligned with Haystack defaults.

I also updated this PR description: #3194 (comment)