test: add tests for leave federation endpoint

gateway/cli/src/main.rs

@@ -160,9 +160,10 @@ async fn main() -> anyhow::Result<()> {
             print_response(response).await;
         }
         Commands::LeaveFed { federation_id } => {
-            client()
+            let response = client()
                 .leave_federation(LeaveFedPayload { federation_id })
                 .await?;
+            print_response(response).await;
         }
         Commands::Backup { federation_id } => {
             client().backup(BackupPayload { federation_id }).await?;

gateway/ln-gateway/src/lib.rs

@@ -964,7 +964,16 @@ impl Gateway {
         Err(GatewayError::Disconnected)
     }
 
-    pub async fn handle_leave_federation(&mut self, payload: LeaveFedPayload) -> Result<()> {
+    pub async fn handle_leave_federation(
+        &mut self,
+        payload: LeaveFedPayload,
+    ) -> Result<FederationInfo> {
+        let federation_info = {
+            let client = self.select_client(payload.federation_id).await?;
+            self.make_federation_info(client.value(), payload.federation_id)
+                .await
+        };
+
         // TODO: This should optimistically try to contact the federation to remove the
         // registration record
         let _client_joining_lock = self.client_joining_lock.lock().await;
@@ -977,7 +986,8 @@ impl Gateway {
         .await;
         dbtx.commit_tx_result()
             .await
-            .map_err(GatewayError::DatabaseError)
+            .map_err(GatewayError::DatabaseError)?;
+        Ok(federation_info)
     }
 
     pub async fn handle_backup_msg(

gateway/ln-gateway/src/rpc/rpc_client.rs

@@ -83,7 +83,10 @@ impl GatewayRpcClient {
         self.call_post(url, payload).await
     }
 
-    pub async fn leave_federation(&self, payload: LeaveFedPayload) -> GatewayRpcResult<()> {
+    pub async fn leave_federation(
+        &self,
+        payload: LeaveFedPayload,
+    ) -> GatewayRpcResult<FederationInfo> {
         let url = self.base_url.join("/leave-fed").expect("invalid base url");
         self.call_post(url, payload).await
     }

gateway/ln-gateway/src/rpc/rpc_server.rs

@@ -183,8 +183,8 @@ async fn leave_fed(
     Extension(mut gateway): Extension<Gateway>,
     Json(payload): Json<LeaveFedPayload>,
 ) -> Result<impl IntoResponse, GatewayError> {
-    gateway.handle_leave_federation(payload).await?;
-    Ok(Json(json!(())))
+    let fed = gateway.handle_leave_federation(payload).await?;
+    Ok(Json(json!(fed)))
 }
 
 /// Backup a gateway actor state

gateway/ln-gateway/tests/integration_tests.rs

@@ -1168,6 +1168,53 @@ async fn test_gateway_shows_info_about_all_connected_federations() -> anyhow::Re
     .await
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn test_gateway_can_leave_connected_federations() -> anyhow::Result<()> {
+    multi_federation_test(
+        LightningNodeType::Lnd,
+        |gateway, rpc, fed1, fed2, _| async move {
+            assert_eq!(rpc.get_info().await.unwrap().federations.len(), 0);
+
+            let id1 = fed1.invite_code().federation_id();
+            let id2 = fed2.invite_code().federation_id();
+
+            connect_federations(&rpc, &[fed1, fed2]).await.unwrap();
+
+            let info = rpc.get_info().await.unwrap();
+            assert_eq!(info.federations.len(), 2);
+            assert!(info
+                .federations
+                .iter()
+                .any(|info| info.federation_id == id1 && info.balance_msat == Amount::ZERO));
+            assert!(info
+                .federations
+                .iter()
+                .any(|info| info.federation_id == id2 && info.balance_msat == Amount::ZERO));
+
+            // remove first connected federation
+            let fed_info = rpc
+                .leave_federation(LeaveFedPayload { federation_id: id1 })
+                .await
+                .unwrap();
+            assert_eq!(fed_info.federation_id, id1);
+
+            // remove second connected federation
+            let fed_info = rpc
+                .leave_federation(LeaveFedPayload { federation_id: id2 })
+                .await
+                .unwrap();
+            assert_eq!(fed_info.federation_id, id2);
+
+            let info = rpc.get_info().await.unwrap();
+            assert_eq!(info.federations.len(), 0);
+
+            drop(gateway); // keep until the end to avoid the gateway shutting down too early
+            Ok(())
+        },
+    )
+    .await
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn test_gateway_shows_balance_for_any_connected_federation() -> anyhow::Result<()> {
     multi_federation_test(