`UpdateByFilterAsyncTest`, `CountDocumentsByFilterAsyncTest`, `CountUniqueMetadataByFilterAsyncTest`

[davidsbatista]

NOTES:

• Tests should be written into haystack/testing/document_store_async.py
• Use async def for all test methods
• Decorate each test method with @pytest.mark.asyncio
• Rely on an async-compatible document_store fixture (to be provided by the concrete test class in each integration)
• Use await on all *_async() calls
• Use write_documents_async / count_documents_async in setup steps (not the sync variants), so the full async path is exercised end-to-end
• Open the PR to the async-mixin-tests feature branch

UpdateByFilterAsyncTest(FilterableDocsFixtureMixin)

Mirrors: UpdateByFilterTest

Test	Description
test_update_by_filter_async	Update meta on matching docs, verify updated and non-updated docs
test_update_by_filter_no_matches_async	Filter matches nothing, returns 0, store count unchanged
test_update_by_filter_multiple_fields_async	Update multiple meta fields at once
test_update_by_filter_advanced_filters_async	AND/OR compound filter updates

Use inspect.signature(document_store.update_by_filter_async) to detect optional refresh parameter.

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CountDocumentsByFilterAsyncTest

Mirrors: CountDocumentsByFilterTest

Test	Description
test_count_documents_by_filter_simple_async	Simple equality filter
test_count_documents_by_filter_compound_async	AND filter
test_count_documents_by_filter_no_matches_async	Filter matches nothing, returns 0
test_count_documents_by_filter_empty_collection_async	Empty store returns 0

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CountUniqueMetadataByFilterAsyncTest

Mirrors: CountUniqueMetadataByFilterTest

Test	Description
test_count_unique_metadata_by_filter_all_documents_async	No filter — distinct counts for all docs across multiple fields
test_count_unique_metadata_by_filter_with_filter_async	Simple filter narrows the distinct value counts
test_count_unique_metadata_by_filter_with_multiple_filters_async	AND compound filter