diff --git a/tests/unit/test_router.py b/tests/unit/test_router.py
index ef36e0ab4b4180b3ed5e5746d984691efd2b5150..067e78a9be0f5b17e555ab3512c24eac88d15e86 100644
--- a/tests/unit/test_router.py
+++ b/tests/unit/test_router.py
@@ -149,6 +149,13 @@ def routes_4():
     ]
 
 
+@pytest.fixture
+def route_single_utterance():
+    return [
+        Route(name="Route 3", utterances=["Hello"]),
+    ]
+
+
 @pytest.fixture
 def dynamic_routes():
     return [
@@ -251,6 +258,39 @@ class TestSemanticRouter:
         )
         assert route_layer.score_threshold == openai_encoder.score_threshold
 
+    def test_add_single_utterance(
+        self, routes, route_single_utterance, openai_encoder, index_cls
+    ):
+        index = init_index(index_cls)
+        route_layer = SemanticRouter(
+            encoder=openai_encoder,
+            routes=routes,
+            index=index,
+            auto_sync="local",
+        )
+        route_layer.add(routes=[route_single_utterance])
+        assert route_layer.score_threshold == openai_encoder.score_threshold
+        if index_cls is PineconeIndex:
+            time.sleep(PINECONE_SLEEP)  # allow for index to be updated
+        _ = route_layer("Hello")
+        assert len(route_layer.index.get_utterances()) == 6
+
+    def test_init_and_add_single_utterance(
+        self, route_single_utterance, openai_encoder, index_cls
+    ):
+        index = init_index(index_cls)
+        route_layer = SemanticRouter(
+            encoder=openai_encoder,
+            index=index,
+            auto_sync="local",
+        )
+        if index_cls is PineconeIndex:
+            time.sleep(PINECONE_SLEEP)  # allow for index to be updated
+        route_layer.add(routes=[route_single_utterance])
+        assert route_layer.score_threshold == openai_encoder.score_threshold
+        _ = route_layer("Hello")
+        assert len(route_layer.index.get_utterances()) == 1
+
     def test_delete_index(self, openai_encoder, routes, index_cls):
         # TODO merge .delete_index() and .delete_all() and get working
         index = init_index(index_cls)