Add change_position_margin api of future

src/api.rs

@@ -88,6 +88,7 @@ pub enum Futures {
     IndexInfo,
     ChangeInitialLeverage,
     ChangeMarginType,
+    ChangePositionMargin,
     Account,
     OpenOrders,
     UserDataStream,
@@ -163,6 +164,7 @@ impl From<API> for String {
                 Futures::IndexInfo => "/fapi/v1/indexInfo",
                 Futures::ChangeInitialLeverage => "/fapi/v1/leverage",
                 Futures::ChangeMarginType => "/fapi/v1/marginType",
+                Futures::ChangePositionMargin => "/fapi/v1/positionMargin",
                 Futures::Account => "/fapi/v2/account",
                 Futures::OpenOrders => "/fapi/v1/openOrders",
                 Futures::UserDataStream => "/fapi/v1/listenKey",

src/futures/account.rs

@@ -612,6 +612,22 @@ impl FuturesAccount {
             .map(|_| ())
     }
 
+    pub fn change_position_margin<S>(&self, symbol: S, amount: f64, is_adding_margin: bool) -> Result<()>
+    where
+        S: Into<String>,
+    {
+        let mut parameters: BTreeMap<String, String> = BTreeMap::new();
+        let margin = if is_adding_margin { "1" } else { "2" };
+        parameters.insert("symbol".into(), symbol.into());
+        parameters.insert("amount".into(), amount.to_string());
+        parameters.insert("type".into(), margin.into());
+
+        let request = build_signed_request(parameters, self.recv_window)?;
+        self.client
+            .post_signed::<Empty>(API::Futures(Futures::ChangePositionMargin), request)
+            .map(|_| ())
+    }
+
     pub fn change_position_mode(&self, dual_side_position: bool) -> Result<()> {
         let mut parameters: BTreeMap<String, String> = BTreeMap::new();
         let dual_side = if dual_side_position { "true" } else { "false" };

tests/futures_account_tests.rs

@@ -61,6 +61,27 @@ mod tests {
         mock.assert();
     }
 
+    #[test]
+    fn change_position_margin() {
+        let mut server = Server::new();
+        let mock = server.mock("POST", "/fapi/v1/positionMargin")
+            .with_header("content-type", "application/json;charset=UTF-8")
+            .match_query(Matcher::Regex(
+                "amount=100&recvWindow=1234&symbol=BTCUSDT&timestamp=\\d+&type=1&signature=.*".into(),
+            ))
+            .with_body_from_file("tests/mocks/futures/account/change_position_margin.json")
+            .create();
+
+        let config = Config::default()
+            .set_futures_rest_api_endpoint(server.url())
+            .set_recv_window(1234);
+        let account: FuturesAccount = Binance::new_with_config(None, None, &config);
+        let _ = env_logger::try_init();
+        account.change_position_margin("BTCUSDT", 100., true).unwrap();
+
+        mock.assert();
+    }
+
     #[test]
     fn cancel_all_open_orders() {
         let mut server = Server::new();

tests/mocks/futures/account/change_position_margin.json

@@ -0,0 +1,6 @@
+{
+    "amount": 100.0,
+    "code": 200,
+    "msg": "Successfully modify position margin.",
+    "type": 1
+}