update tests

tests/unit/test_splitters.py

 import pytest
 from unittest.mock import Mock
 from semantic_router.utils.splitters import semantic_splitter
+from semantic_router.schema import Conversation, Message
 
 
 def test_semantic_splitter_consecutive_similarity_drop():
@@ -43,3 +44,23 @@ def test_semantic_splitter_invalid_method():
 
     with pytest.raises(ValueError):
         semantic_splitter(mock_encoder, docs, threshold, split_method)
+
+
+def test_split_by_topic():
+    mock_encoder = Mock()
+    mock_encoder.return_value = [[0.5, 0], [0, 0.5]]
+
+    messages = [
+        Message(role="User", content="What is the latest news?"),
+        Message(role="Bot", content="How is the weather today?"),
+    ]
+    conversation = Conversation(messages=messages)
+
+    result = conversation.split_by_topic(
+        encoder=mock_encoder, threshold=0.5, split_method="consecutive_similarity_drop"
+    )
+
+    assert result == {
+        "split 1": ["User: What is the latest news?"],
+        "split 2": ["Bot: How is the weather today?"],
+    }