fix: apply dedup window + max_deliver to existing jetstream stream/consumer

crates/adapters/nats/src/tests/consumer.rs

@@ -44,3 +44,46 @@ fn decode_message_rejects_a_malformed_id() {
 fn decode_message_rejects_garbage() {
     assert!(decode_message(b"{not json").is_err());
 }
+
+#[test]
+fn stream_with_the_default_window_is_updated_and_keeps_other_fields() {
+    let existing = StreamConfig {
+        name: "S".into(),
+        max_messages: 42,
+        duplicate_window: std::time::Duration::from_secs(120),
+        ..Default::default()
+    };
+    let updated = stream_config_update(&existing).unwrap();
+    assert_eq!(updated.duplicate_window, DEDUP_WINDOW);
+    assert_eq!(updated.max_messages, 42);
+    assert_eq!(updated.name, "S");
+}
+
+#[test]
+fn stream_with_the_right_window_is_left_alone() {
+    let existing = StreamConfig {
+        duplicate_window: DEDUP_WINDOW,
+        ..Default::default()
+    };
+    assert!(stream_config_update(&existing).is_none());
+}
+
+#[test]
+fn consumer_max_deliver_drift_is_updated() {
+    let existing = jetstream::consumer::Config {
+        durable_name: Some("c".into()),
+        filter_subject: "a.>".into(),
+        max_deliver: -1,
+        ack_wait: ACK_WAIT,
+        ..Default::default()
+    };
+    let updated = consumer_config_update(&existing, 5).unwrap();
+    assert_eq!(updated.max_deliver, 5);
+    assert_eq!(updated.durable_name.as_deref(), Some("c"));
+    assert_eq!(updated.filter_subject, "a.>");
+    let same = jetstream::consumer::Config {
+        max_deliver: 5,
+        ..existing
+    };
+    assert!(consumer_config_update(&same, 5).is_none());
+}