Add/test faiss (#7809)

# What
- Add missing test cases to faiss vectore stores

tests/integration_tests/vectorstores/test_faiss.py

@@ -47,6 +47,25 @@ def test_faiss_vector_sim() -> None:
     assert output == [Document(page_content="foo")]
 
 
+def test_similarity_search_with_score_by_vector() -> None:
+    """Test vector similarity with score by vector."""
+    texts = ["foo", "bar", "baz"]
+    docsearch = FAISS.from_texts(texts, FakeEmbeddings())
+    index_to_id = docsearch.index_to_docstore_id
+    expected_docstore = InMemoryDocstore(
+        {
+            index_to_id[0]: Document(page_content="foo"),
+            index_to_id[1]: Document(page_content="bar"),
+            index_to_id[2]: Document(page_content="baz"),
+        }
+    )
+    assert docsearch.docstore.__dict__ == expected_docstore.__dict__
+    query_vec = FakeEmbeddings().embed_query(text="foo")
+    output = docsearch.similarity_search_with_score_by_vector(query_vec, k=1)
+    assert len(output) == 1
+    assert output[0][0] == Document(page_content="foo")
+
+
 def test_faiss_mmr() -> None:
     texts = ["foo", "foo", "fou", "foy"]
     docsearch = FAISS.from_texts(texts, FakeEmbeddings())
@@ -61,6 +80,48 @@ def test_faiss_mmr() -> None:
     assert output[1][0] != Document(page_content="foo")
 
 
+def test_faiss_mmr_with_metadatas() -> None:
+    texts = ["foo", "foo", "fou", "foy"]
+    metadatas = [{"page": i} for i in range(len(texts))]
+    docsearch = FAISS.from_texts(texts, FakeEmbeddings(), metadatas=metadatas)
+    query_vec = FakeEmbeddings().embed_query(text="foo")
+    output = docsearch.max_marginal_relevance_search_with_score_by_vector(
+        query_vec, k=10, lambda_mult=0.1
+    )
+    assert len(output) == len(texts)
+    assert output[0][0] == Document(page_content="foo", metadata={"page": 0})
+    assert output[0][1] == 0.0
+    assert output[1][0] != Document(page_content="foo", metadata={"page": 0})
+
+
+def test_faiss_mmr_with_metadatas_and_filter() -> None:
+    texts = ["foo", "foo", "fou", "foy"]
+    metadatas = [{"page": i} for i in range(len(texts))]
+    docsearch = FAISS.from_texts(texts, FakeEmbeddings(), metadatas=metadatas)
+    query_vec = FakeEmbeddings().embed_query(text="foo")
+    output = docsearch.max_marginal_relevance_search_with_score_by_vector(
+        query_vec, k=10, lambda_mult=0.1, filter={"page": 1}
+    )
+    assert len(output) == len(texts)
+    assert output[0][0] == Document(page_content="foo", metadata={"page": 1})
+    assert output[0][1] == 0.0
+    assert output[1][0] != Document(page_content="foo", metadata={"page": 1})
+
+
+def test_faiss_mmr_with_metadatas_and_list_filter() -> None:
+    texts = ["foo", "foo", "fou", "foy"]
+    metadatas = [{"page": i} if i <= 3 else {"page": 3} for i in range(len(texts))]
+    docsearch = FAISS.from_texts(texts, FakeEmbeddings(), metadatas=metadatas)
+    query_vec = FakeEmbeddings().embed_query(text="foo")
+    output = docsearch.max_marginal_relevance_search_with_score_by_vector(
+        query_vec, k=10, lambda_mult=0.1, filter={"page": [0, 1, 2]}
+    )
+    assert len(output) == len(texts)
+    assert output[0][0] == Document(page_content="foo", metadata={"page": 0})
+    assert output[0][1] == 0.0
+    assert output[1][0] != Document(page_content="foo", metadata={"page": 0})
+
+
 def test_faiss_with_metadatas() -> None:
     """Test end to end construction and search."""
     texts = ["foo", "bar", "baz"]