[AUR-392, AUR-413, AUR-414] Define base vector store, and make use of ChromaVectorStore from llama_index. Indexing and retrieving vectors with vector store (#18)

Design the base interface of vector store, and apply it to the Chroma Vector Store (wrapped around llama_index's implementation). Provide the pipelines to populate and retrieve from vector store.

tests/test_vectorstore.py

@@ -0,0 +1,61 @@
+from kotaemon.documents.base import Document
+from kotaemon.vectorstores import ChromaVectorStore
+
+
+class TestChromaVectorStore:
+    def test_add(self, tmp_path):
+        """Test that the DB add correctly"""
+        db = ChromaVectorStore(path=str(tmp_path))
+
+        embeddings = [[0.1, 0.2, 0.3], [0.4, 0.5, 0.6]]
+        metadatas = [{"a": 1, "b": 2}, {"a": 3, "b": 4}]
+        ids = ["1", "2"]
+
+        assert db._collection.count() == 0, "Expected empty collection"
+        output = db.add(embeddings=embeddings, metadatas=metadatas, ids=ids)
+        assert output == ids, "Expected output to be the same as ids"
+        assert db._collection.count() == 2, "Expected 2 added entries"
+
+    def test_add_from_docs(self, tmp_path):
+        db = ChromaVectorStore(path=str(tmp_path))
+
+        embeddings = [[0.1, 0.2, 0.3], [0.4, 0.5, 0.6]]
+        metadatas = [{"a": 1, "b": 2}, {"a": 3, "b": 4}]
+        documents = [
+            Document(embedding=embedding, metadata=metadata)
+            for embedding, metadata in zip(embeddings, metadatas)
+        ]
+        assert db._collection.count() == 0, "Expected empty collection"
+        output = db.add_from_docs(documents)
+        assert len(output) == 2, "Expected outputing 2 ids"
+        assert db._collection.count() == 2, "Expected 2 added entries"
+
+    def test_delete(self, tmp_path):
+        db = ChromaVectorStore(path=str(tmp_path))
+
+        embeddings = [[0.1, 0.2, 0.3], [0.4, 0.5, 0.6], [0.7, 0.8, 0.9]]
+        metadatas = [{"a": 1, "b": 2}, {"a": 3, "b": 4}, {"a": 5, "b": 6}]
+        ids = ["a", "b", "c"]
+
+        db.add(embeddings=embeddings, metadatas=metadatas, ids=ids)
+        assert db._collection.count() == 3, "Expected 3 added entries"
+        db.delete(ids=["a", "b"])
+        assert db._collection.count() == 1, "Expected 1 remaining entry"
+        db.delete(ids=["c"])
+        assert db._collection.count() == 0, "Expected 0 remaining entry"
+
+    def test_query(self, tmp_path):
+        db = ChromaVectorStore(path=str(tmp_path))
+
+        embeddings = [[0.1, 0.2, 0.3], [0.4, 0.5, 0.6], [0.7, 0.8, 0.9]]
+        metadatas = [{"a": 1, "b": 2}, {"a": 3, "b": 4}, {"a": 5, "b": 6}]
+        ids = ["a", "b", "c"]
+
+        db.add(embeddings=embeddings, metadatas=metadatas, ids=ids)
+
+        _, sim, out_ids = db.query(embedding=[0.1, 0.2, 0.3], top_k=1)
+        assert sim == [0.0]
+        assert out_ids == ["a"]
+
+        _, _, out_ids = db.query(embedding=[0.42, 0.52, 0.53], top_k=1)
+        assert out_ids == ["b"]