Merge #1013

1013: Federated Search Addition r=sanders41 a=MuddyHope

# Pull Request

## Related issue
Fixes #1009

## What does this PR do?
- Adds the federated search to the `multi-search` method

## PR checklist
Please check if your PR fulfills the following requirements:
- [x] Does this PR fix an existing issue, or have you listed the changes applied in the PR description (and why they are needed)?
- [x] Have you read the contributing guidelines?
- [x] Have you made sure that the title is accurate and descriptive of the changes?

Thank you so much for contributing to Meilisearch!


Co-authored-by: MuddyHope <daktarisun@gmail.com>
Co-authored-by: MuddyHope <60110059+MuddyHope@users.noreply.github.com>

meilisearch/client.py

@@ -219,14 +219,19 @@ def index(self, uid: str) -> Index:
             return Index(self.config, uid=uid)
         raise ValueError("The index UID should not be None")
 
-    def multi_search(self, queries: Sequence[Mapping[str, Any]]) -> Dict[str, List[Dict[str, Any]]]:
+    def multi_search(
+        self, queries: Sequence[Mapping[str, Any]], federation: Optional[Dict[str, Any]] = None
+    ) -> Dict[str, List[Dict[str, Any]]]:
         """Multi-index search.
 
         Parameters
         ----------
         queries:
             List of dictionaries containing the specified indexes and their search queries
             https://www.meilisearch.com/docs/reference/api/search#search-in-an-index
+        federation: (optional):
+            Dictionary containing offset and limit
+            https://www.meilisearch.com/docs/reference/api/multi_search
 
         Returns
         -------
@@ -240,7 +245,7 @@ def multi_search(self, queries: Sequence[Mapping[str, Any]]) -> Dict[str, List[D
         """
         return self.http.post(
             f"{self.config.paths.multi_search}",
-            body={"queries": queries},
+            body={"queries": queries, "federation": federation},
         )
 
     def get_all_stats(self) -> Dict[str, Any]:

tests/client/test_client_multi_search_meilisearch.py

@@ -1,6 +1,7 @@
 import pytest
 
 from meilisearch.errors import MeilisearchApiError
+from tests.common import INDEX_UID
 
 
 def test_basic_multi_search(client, empty_index):
@@ -32,3 +33,45 @@ def test_multi_search_on_no_index(client):
     """Tests multi-search on a non existing index."""
     with pytest.raises(MeilisearchApiError):
         client.multi_search([{"indexUid": "indexDoesNotExist", "q": ""}])
+
+
+def test_multi_search_with_no_value_in_federation(client, empty_index, index_with_documents):
+    """Tests multi-search with federation, but no value"""
+    index_with_documents()
+    empty_index("indexB")
+    response = client.multi_search(
+        [{"indexUid": INDEX_UID, "q": ""}, {"indexUid": "indexB", "q": ""}], {}
+    )
+    assert "results" not in response
+    assert len(response["hits"]) > 0
+    assert "_federation" in response["hits"][0]
+    assert response["limit"] == 20
+    assert response["offset"] == 0
+
+
+def test_multi_search_with_offset_and_limit_in_federation(client, index_with_documents):
+    """Tests multi-search with federation, with offset and limit value"""
+    index_with_documents()
+    response = client.multi_search([{"indexUid": INDEX_UID, "q": ""}], {"offset": 2, "limit": 2})
+
+    assert "results" not in response
+    assert len(response["hits"]) == 2
+    assert "_federation" in response["hits"][0]
+    assert response["limit"] == 2
+    assert response["offset"] == 2
+
+
+def test_multi_search_with_federation_options(client, index_with_documents):
+    """Tests multi-search with federation, with federation options"""
+    index_with_documents()
+    response = client.multi_search(
+        [{"indexUid": INDEX_UID, "q": "", "federationOptions": {"weight": 0.99}}], {"limit": 2}
+    )
+
+    assert "results" not in response
+    assert isinstance(response["hits"], list)
+    assert len(response["hits"]) == 2
+    assert response["hits"][0]["_federation"]["indexUid"] == INDEX_UID
+    assert response["hits"][0]["_federation"]["weightedRankingScore"] >= 0.99
+    assert response["limit"] == 2
+    assert response["offset"] == 0