Add estimate_fee to batch methods

Author: RCasatta

src/batch.rs

@@ -49,6 +49,13 @@ impl Batch {
         self.calls
             .push((String::from("blockchain.transaction.get"), params));
     }
+
+    /// Add one `blockchain.estimatefee` request to the batch queue
+    pub fn estimate_fee(&mut self, number: usize) {
+        let params = vec![Param::Usize(number)];
+        self.calls
+            .push((String::from("blockchain.estimatefee"), params));
+    }
 }
 
 impl std::iter::IntoIterator for Batch {

src/client.rs

@@ -566,6 +566,7 @@ impl<S: Read + Write> Client<S> {
 
         Ok(serde_json::from_value(result)?)
     }
+
     /// Batch version of [`script_list_unspent`](#method.script_list_unspent).
     ///
     /// Takes a list of scripts and returns a list of a list of utxos.
@@ -604,6 +605,17 @@ impl<S: Read + Write> Client<S> {
         impl_batch_call!(self, txids, transaction_get)
     }
 
+    /// Batch version of [`estimate_fee`](#method.estimate_fee).
+    ///
+    /// Takes a list of `numbers` of blocks and returns a list of fee required in
+    /// **Satoshis per kilobyte** to confirm a transaction in the given number of blocks.
+    pub fn batch_estimate_fee<'s, I>(&mut self, numbers: I) -> Result<Vec<f64>, Error>
+    where
+        I: IntoIterator<Item = usize>,
+    {
+        impl_batch_call!(self, numbers, estimate_fee)
+    }
+
     /// Broadcasts a transaction to the network.
     pub fn transaction_broadcast(&mut self, tx: &Transaction) -> Result<Txid, Error> {
         let buffer: Vec<u8> = serialize(tx);
@@ -848,6 +860,18 @@ mod test {
         impl_test_conclusion!(test_case, client.stream);
     }
 
+    #[test]
+    fn test_batch_estimate_fee() {
+        let test_case = "batch_estimate_fee";
+        let mut client = impl_test_prelude!(test_case);
+
+        let resp = client.batch_estimate_fee(vec![10, 20]).unwrap();
+        assert_eq!(resp[0], 10.0);
+        assert_eq!(resp[1], 20.0);
+
+        impl_test_conclusion!(test_case, client.stream);
+    }
+
     #[test]
     fn test_transaction_get() {
         use bitcoin::hashes::hex::FromHex;

test_data/batch_estimate_fee.in

@@ -0,0 +1,2 @@
+{"id":0,"jsonrpc":"2.0","result":10.0}
+{"id":0,"jsonrpc":"2.0","result":20.0}

test_data/batch_estimate_fee.out

@@ -0,0 +1,2 @@
+{"jsonrpc":"2.0","id":0,"method":"blockchain.estimatefee","params":[10]}
+{"jsonrpc":"2.0","id":1,"method":"blockchain.estimatefee","params":[20]}