`GetMetadataFieldsInfoAsyncTest`, `GetMetadataFieldMinMaxAsyncTest`, `GetMetadataFieldUniqueValuesAsyncTest`

[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

GetMetadataFieldsInfoAsyncTest

Mirrors: GetMetadataFieldsInfoTest

Test	Description
test_get_metadata_fields_info_async	After writing docs, returned dict contains expected field names and each has a "type" key
test_get_metadata_fields_info_empty_collection_async	Empty store returns {}

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GetMetadataFieldMinMaxAsyncTest

Mirrors: GetMetadataFieldMinMaxTest

Test	Description
test_get_metadata_field_min_max_numeric_async	Integer field, correct min/max
test_get_metadata_field_min_max_float_async	Float field, correct min/max (use pytest.approx)
test_get_metadata_field_min_max_single_value_async	Single doc: min == max
test_get_metadata_field_min_max_empty_collection_async	Empty store: {"min": None, "max": None}
test_get_metadata_field_min_max_meta_prefix_async	Field names with "meta." prefix are handled

---

GetMetadataFieldUniqueValuesAsyncTest

Mirrors: GetMetadataFieldUniqueValuesTest

Test	Description
test_get_metadata_field_unique_values_basic_async	Returns correct set of unique values; inspects signature for search_term, from_/offset, size/limit params