Add 'build_output' endpoint to owner api (#641)

* add 'build_output' endpoint to owner api

* merge fix

controller/tests/build_output.rs

@@ -0,0 +1,101 @@
+// Copyright 2021 The Grin Developers
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#[macro_use]
+extern crate log;
+extern crate grin_wallet_controller as wallet;
+extern crate grin_wallet_impls as impls;
+extern crate grin_wallet_util;
+
+use grin_wallet_libwallet as libwallet;
+use grin_wallet_util::grin_core::core::OutputFeatures;
+use grin_wallet_util::grin_keychain::{
+	mnemonic, BlindingFactor, ExtKeychain, ExtKeychainPath, Keychain, SwitchCommitmentType,
+};
+use grin_wallet_util::grin_util::{secp, ZeroingString};
+use impls::test_framework::LocalWalletClient;
+use rand::{thread_rng, Rng};
+use std::sync::atomic::Ordering;
+use std::thread;
+use std::time::Duration;
+
+#[macro_use]
+mod common;
+use common::{clean_output_dir, create_wallet_proxy, setup};
+
+fn build_output_test_impl(test_dir: &'static str) -> Result<(), libwallet::Error> {
+	// Generate seed so we can verify the blinding factor is derived correctly
+	let seed: [u8; 32] = thread_rng().gen();
+	let keychain = ExtKeychain::from_seed(&seed, false).unwrap();
+	let mnemonic = mnemonic::from_entropy(&seed).unwrap();
+
+	// Create a new proxy to simulate server and wallet responses
+	let mut wallet_proxy = create_wallet_proxy(test_dir);
+	let stopper = wallet_proxy.running.clone();
+
+	create_wallet_and_add!(
+		client1,
+		wallet1,
+		mask1_i,
+		test_dir,
+		"wallet1",
+		Some(ZeroingString::from(mnemonic)),
+		&mut wallet_proxy,
+		false
+	);
+
+	let mask1 = (&mask1_i).as_ref();
+
+	// Set the wallet proxy listener running
+	thread::spawn(move || {
+		if let Err(e) = wallet_proxy.run() {
+			error!("Wallet Proxy error: {}", e);
+		}
+	});
+
+	let secp = secp::Secp256k1::with_caps(secp::ContextFlag::Commit);
+	let features = OutputFeatures::Plain;
+	let amount = 60_000_000_000;
+	wallet::controller::owner_single_use(Some(wallet1.clone()), mask1, None, |sender_api, m| {
+		let built_output = sender_api.build_output(m, features, amount)?;
+
+		let key_id = built_output.key_id;
+		assert_eq!(key_id.to_path(), ExtKeychainPath::new(3, 0, 0, 0, 0));
+
+		let blind = built_output.blind;
+		let key = keychain.derive_key(amount, &key_id, SwitchCommitmentType::Regular)?;
+		assert_eq!(blind, BlindingFactor::from_secret_key(key.clone()));
+
+		let output = built_output.output;
+		assert_eq!(output.features(), features);
+		assert_eq!(output.commitment(), secp.commit(amount, key)?);
+		output.verify_proof()?;
+
+		Ok(())
+	})?;
+
+	// let logging finish
+	stopper.store(false, Ordering::Relaxed);
+	thread::sleep(Duration::from_millis(200));
+	Ok(())
+}
+
+#[test]
+fn build_output() {
+	let test_dir = "test_output/build_output";
+	setup(test_dir);
+	if let Err(e) = build_output_test_impl(test_dir) {
+		panic!("Libwallet Error: {} - {}", e, e.backtrace().unwrap());
+	}
+	clean_output_dir(test_dir);
+}