Implement count_document for WeaviateDocumentStore

integrations/weaviate/src/haystack_integrations/document_stores/weaviate/document_store.py

@@ -188,7 +188,9 @@ def from_dict(cls, data: Dict[str, Any]) -> "WeaviateDocumentStore":
         )
 
     def count_documents(self) -> int:
-        return 0
+        collection_name = self._collection_settings["class"]
+        res = self._client.query.aggregate(collection_name).with_meta_count().do()
+        return res.get("data", {}).get("Aggregate", {}).get(collection_name, [{}])[0].get("meta", {}).get("count", 0)
 
     def filter_documents(self, filters: Optional[Dict[str, Any]] = None) -> List[Document]:  # noqa: ARG002
         return []

integrations/weaviate/tests/test_document_store.py

@@ -1,6 +1,7 @@
 from unittest.mock import MagicMock, patch
 
 import pytest
+from haystack.testing.document_store import CountDocumentsTest
 from haystack_integrations.document_stores.weaviate.document_store import (
     DOCUMENT_COLLECTION_PROPERTIES,
     WeaviateDocumentStore,
@@ -16,7 +17,7 @@
 )
 
 
-class TestWeaviateDocumentStore:
+class TestWeaviateDocumentStore(CountDocumentsTest):
     @pytest.fixture
     def document_store(self, request) -> WeaviateDocumentStore:
         # Use a different index for each test so we can run them in parallel
@@ -197,3 +198,7 @@ def test_from_dict(self, _mock_weaviate):
         assert document_store._additional_config.grpc_port_experimental == 12345
         assert document_store._additional_config.connection_config.session_pool_connections == 20
         assert document_store._additional_config.connection_config.session_pool_maxsize == 20
+
+    def test_count_not_empty(self, document_store):
+        # Skipped for the time being as we don't support writing documents
+        pass