diff --git a/tests/test.rs b/tests/test.rs
index e093a64..3855772 100644
--- a/tests/test.rs
+++ b/tests/test.rs
@@ -319,6 +319,7 @@ mod request {
         }
 
         pub mod scheduling {
+            use time::format_description::well_known::Iso8601;
             use tower::ServiceExt;
 
             pub async fn create_scheduled_message(
@@ -335,6 +336,14 @@ mod request {
                 */
                 let now = time::OffsetDateTime::now_utc();
                 let scheduled = now + std::time::Duration::from_secs(60 * 60);
+                let scheduled = match scheduled.format(&Iso8601::DEFAULT) {
+                    Ok(t) => t,
+                    Err(err) => {
+                        assert!(false, "Error: {err:?}");
+                        String::new()
+                    }
+                };
+
                 let payload = serde_json::json!({
                     "scheduled": scheduled,
                     "status": textsender_models::message::scheduling::PENDING,