diff --git a/crates/optimism/flashblocks/src/ws/stream.rs b/crates/optimism/flashblocks/src/ws/stream.rs
index c18857eee3c..a2aad69eef6 100644
--- a/crates/optimism/flashblocks/src/ws/stream.rs
+++ b/crates/optimism/flashblocks/src/ws/stream.rs
@@ -182,7 +182,7 @@ mod tests {
     use alloy_primitives::bytes::Bytes;
     use brotli::enc::BrotliEncoderParams;
     use std::future;
-    use tokio_tungstenite::tungstenite::Error;
+    use tokio_tungstenite::tungstenite::{Error, Utf8Bytes};
 
     /// A `FakeConnector` creates [`FakeStream`].
     ///
@@ -284,4 +284,18 @@ mod tests {
 
         assert_eq!(actual_messages, expected_messages);
     }
+
+    #[tokio::test]
+    async fn test_stream_fails_to_decode_non_binary_message() {
+        let messages = FakeConnector::from([Ok(Message::Text(Utf8Bytes::from("test")))]);
+        let ws_url = "http://localhost".parse().unwrap();
+        let stream = WsFlashBlockStream::with_connector(ws_url, messages);
+
+        let actual_messages: Vec<_> =
+            stream.map(Result::unwrap_err).map(|e| format!("{e}")).collect().await;
+        let expected_messages =
+            vec!["Unexpected websocket message: Text(Utf8Bytes(b\"test\"))".to_owned()];
+
+        assert_eq!(actual_messages, expected_messages);
+    }
 }