Testing Framework [WIP] and new command line options to configure wallet ports and directories (#65)

* Beginning to refactor server tests
* Extended test framework to include running wallet servers and miners. Also some changes to the wallet reciever api to include a wallet config and set the data directly for the wallet file explicitly rather than assuming it's always in the working dir.
* Adding wallet config to main executable
* Adding ability to select wallet server while mining
* Configurable wallet receiver url

api/src/rest.rs

@@ -24,11 +24,13 @@ use std::io::Read;
 use std::net::ToSocketAddrs;
 use std::string::ToString;
 use std::str::FromStr;
+use std::mem;
 
-use iron::{Iron, Request, Response, IronResult, IronError, status, headers};
+use iron::{Iron, Request, Response, IronResult, IronError, status, headers, Listening};
 use iron::method::Method;
 use iron::modifiers::Header;
 use iron::middleware::Handler;
+use iron::error::HttpResult;
 use router::Router;
 use serde::{Serialize, Deserialize};
 use serde::de::DeserializeOwned;
@@ -227,6 +229,8 @@ fn extract_param<ID>(req: &mut Request, param: &'static str) -> IronResult<ID>
 pub struct ApiServer {
 	root: String,
 	router: Router,
+	server_listener: Option<Listening>,
+
 }
 
 impl ApiServer {
@@ -236,12 +240,24 @@ impl ApiServer {
 		ApiServer {
 			root: root,
 			router: Router::new(),
+			server_listener: None,
 		}
 	}
 
 	/// Starts the ApiServer at the provided address.
-	pub fn start<A: ToSocketAddrs>(self, addr: A) -> Result<(), String> {
-		Iron::new(self.router).http(addr).map(|_| ()).map_err(|e| e.to_string())
+	pub fn start<A: ToSocketAddrs>(&mut self, addr: A) -> Result<(), String> {
+		//replace this value to satisfy borrow checker
+		let r = mem::replace(&mut self.router, Router::new());
+		let result = Iron::new(r).http(addr);
+		let return_value = result.as_ref().map(|_| ()).map_err(|e| e.to_string());
+		self.server_listener = Some(result.unwrap());
+		return_value
+	}
+
+	/// Stops the API server
+	pub fn stop(&mut self){
+		let r = mem::replace(&mut self.server_listener, None);
+		r.unwrap().close().unwrap();
 	}
 
 	/// Register a new API endpoint, providing a relative URL for the new

grin/Cargo.toml

@@ -12,6 +12,7 @@ grin_store = { path = "../store" }
 grin_p2p = { path = "../p2p" }
 grin_pool = { path = "../pool" }
 grin_util = { path = "../util" }
+grin_wallet = { path = "../wallet" }
 secp256k1zkp = { path = "../secp256k1zkp" }
 
 env_logger="^0.3.5"
@@ -25,3 +26,4 @@ serde_derive = "~1.0.8"
 tokio-core="^0.1.1"
 tokio-timer="^0.1.0"
 rand = "^0.3"
+tiny-keccak = "1.1"

grin/tests/simulnet.rs

@@ -16,6 +16,10 @@ extern crate grin_grin as grin;
 extern crate grin_core as core;
 extern crate grin_p2p as p2p;
 extern crate grin_chain as chain;
+extern crate grin_api as api;
+extern crate grin_wallet as wallet;
+extern crate secp256k1zkp as secp;
+extern crate tiny_keccak;
 
 extern crate env_logger;
 extern crate futures;
@@ -26,12 +30,249 @@ use std::io;
 use std::thread;
 use std::time;
 use std::default::Default;
+use std::mem;
 
 use futures::{Future, Poll, Async};
 use futures::task::park;
 use tokio_core::reactor;
 use tokio_timer::Timer;
 
+use secp::Secp256k1;
+use secp::key::SecretKey;
+use tiny_keccak::Keccak;
+
+use wallet::WalletConfig;
+
+
+/// Errors that can be returned by LocalServerContainer
+#[derive(Debug)]
+pub enum Error {
+	Internal(String),
+	Argument(String),
+	NotFound,
+}
+
+/// A top-level container to hold everything that might be running
+/// on a server, i.e. server, wallet in send or recieve mode
+
+struct LocalServerContainer {
+    pub working_dir: String,
+    pub server : grin::Server,
+
+    pub enable_mining: bool,
+    pub enable_wallet: bool,
+
+    pub wallet_port: u16,
+    wallet_is_running: bool,
+
+    apis: api::ApiServer,
+}
+
+impl LocalServerContainer {
+    pub fn new(api_addr:String, server_port: u16, event_loop: &reactor::Core) -> Result<LocalServerContainer, Error> {
+      let working_dir = format!("target/test_servers/server-{}", server_port);
+      let mut s = grin::Server::future(
+            grin::ServerConfig{
+                api_http_addr: api_addr,
+                db_root: format!("{}/grin-prop", working_dir),
+                cuckoo_size: 12,
+                p2p_config: p2p::P2PConfig{port: server_port, ..p2p::P2PConfig::default()},
+                ..Default::default()
+            }, &event_loop.handle()).unwrap();
+       Ok((LocalServerContainer {
+           server: s,
+           enable_mining: false,
+           enable_wallet: false,
+           wallet_port: 30000,
+           wallet_is_running: false,
+           working_dir: working_dir,
+
+           apis: api::ApiServer::new("/v1".to_string()),
+       }))
+    }
+
+    /// Starts a wallet daemon to receive and returns the
+    /// listening server url
+
+    pub fn start_wallet(&mut self) -> String {
+      
+        //Just use the server address and port number for the wallet seed now
+      	let url = format!("{}:{}", self.server.config.p2p_config.host,
+                                       self.wallet_port);
+
+	      let mut sha3 = Keccak::new_sha3_256();
+	      sha3.update(url.as_bytes());
+	      let mut seed = [0; 32];
+	      sha3.finalize(&mut seed);
+
+	      let s = Secp256k1::new();
+	      let key = wallet::ExtendedKey::from_seed(&s, &seed[..])
+		         .expect("Error deriving extended key from seed.");
+        
+        println!("Starting the Grin wallet receiving daemon on {} ", self.wallet_port );
+
+        let mut wallet_config = WalletConfig::default();
+        wallet_config.data_file_dir=self.working_dir.clone();
+			  
+			  self.apis.register_endpoint("/receive".to_string(), wallet::WalletReceiver { 
+          key: key,
+          config: wallet_config,
+        });
+
+        let return_url = url.clone();
+			  self.apis.start(url).unwrap_or_else(|e| {
+				    println!("Failed to start Grin wallet receiver: {}.", e);
+			  });
+
+        self.wallet_is_running = true;
+        return return_url;
+    }
+
+    /// Stops the wallet daemon
+    pub fn stop_wallet(&mut self){
+        self.apis.stop();
+    }
+}
+
+struct LocalServerContainerPool {
+    event_loop: reactor::Core,
+
+    base_http_addr: String, 
+    base_port_server: u16,
+    base_port_api: u16,
+    base_port_wallet: u16,
+    server_containers: Vec<LocalServerContainer>,    
+}
+
+impl LocalServerContainerPool {
+    pub fn new() -> Result<LocalServerContainerPool, Error> {
+      let servers = Vec::new();
+      let mut evtlp = reactor::Core::new().unwrap();
+
+      Ok((LocalServerContainerPool{
+        event_loop: evtlp, 
+        base_http_addr : String::from("0.0.0.0"),
+        base_port_server: 15000,
+        base_port_api: 16000,
+        base_port_wallet: 17000,
+        server_containers: servers,
+      }))
+    }
+
+    pub fn create_server(&mut self, enable_mining:bool, enable_wallet:bool ) {
+
+        let server_port = self.base_port_server+self.server_containers.len() as u16;
+        let api_port = self.base_port_api+self.server_containers.len() as u16;
+
+        
+        let api_addr = format!("{}:{}", self.base_http_addr, api_port);
+
+        let mut server_container = LocalServerContainer::new(api_addr, server_port, &self.event_loop).unwrap();
+            
+        server_container.enable_mining = enable_mining;
+        server_container.enable_wallet = enable_wallet;
+
+        //if we want to start a wallet, use this port
+        server_container.wallet_port = self.base_port_wallet+self.server_containers.len() as u16;
+        
+        self.server_containers.push(server_container);
+    }
+
+    /// Connects every server to each other as peers
+    /// 
+
+    pub fn connect_all_peers(&self){
+        /// just pull out all currently active servers, build a list,
+        /// and feed into all servers
+
+        let mut server_addresses:Vec<String> = Vec::new();      
+        for s in &self.server_containers {
+            let server_address = format!("{}:{}", 
+                                     s.server.config.p2p_config.host, 
+                                     s.server.config.p2p_config.port);
+            server_addresses.push(server_address);
+        }
+
+        for a in server_addresses {
+           for s in &self.server_containers {
+              if format!("{}", s.server.config.p2p_config.host) != a {
+                  s.server.connect_peer(a.parse().unwrap()).unwrap();       
+              } 
+           }
+        }
+    }
+
+    ///Starts all servers, with or without mining
+    ///TODO: This should accept a closure so tests can determine what 
+    ///to do when the run is finished
+
+    pub fn start_all_servers(&mut self) {
+        
+        for s in &mut self.server_containers {
+            let mut wallet_url = String::from("http://localhost:13416");
+            if s.enable_wallet == true {
+              wallet_url=s.start_wallet();
+              //Instead of making all sorts of changes to the api server
+              //to support futures, just going to pause this thread for 
+              //half a second for the wallet to start
+              //before continuing
+
+              thread::sleep(time::Duration::from_millis(500));
+            }
+            let mut miner_config = grin::MinerConfig{
+                  enable_mining: true,
+                  burn_reward: true,
+                  wallet_receiver_url : format!("http://{}", wallet_url),
+                  ..Default::default()
+            };
+            if s.enable_wallet == true {
+                miner_config.burn_reward = false;
+            }
+            if s.enable_mining == true {
+                println!("starting Miner on port {}", s.server.config.p2p_config.port);
+                s.server.start_miner(miner_config);        
+            }
+            
+        }
+
+        //borrow copy to allow access in closure
+        let mut server_containers = mem::replace(&mut self.server_containers, Vec::new());
+        //let &mut server_containers = self.server_containers;
+
+        self.event_loop.run(Timer::default().sleep(time::Duration::from_secs(60)).and_then(|_| {
+          //Stop any assocated wallet servers
+          for s in &mut server_containers {
+              if s.wallet_is_running{
+                s.stop_wallet();
+              }
+          }
+          //for s in &mut self.server_containers {  
+            // occasionally 2 peers will connect to each other at the same time
+            //assert!(s.peer_count() >= 4);
+          //}
+          Ok(())
+        }));
+    }
+
+}
+
+/// Just exercises the structures above, creates 5 servers, all starting wallets,
+/// mining and connecting to each other in their own directories
+
+#[test]
+fn simulate_parallel_miners(){
+    env_logger::init();
+    let num_servers=5;
+    
+    let mut server_pool = LocalServerContainerPool::new().unwrap();
+    for n in 0..num_servers {
+        server_pool.create_server(true, true);
+    }
+
+    server_pool.connect_all_peers();
+    server_pool.start_all_servers();
+}
+
 /// Create a network of 5 servers and mine a block, verifying that the block
 /// gets propagated to all.
 #[test]
@@ -52,6 +293,7 @@ fn simulate_block_propagation() {
   for n in 0..5 {
       let s = grin::Server::future(
           grin::ServerConfig{
+            api_http_addr: format!("127.0.0.1:{}", 20000+n),
             db_root: format!("target/grin-prop-{}", n),
             cuckoo_size: 12,
             p2p_config: p2p::P2PConfig{port: 10000+n, ..p2p::P2PConfig::default()},

src/bin/grin.rs

@@ -42,6 +42,8 @@ use daemonize::Daemonize;
 
 use secp::Secp256k1;
 
+use wallet::WalletConfig;
+
 fn main() {
 	env_logger::init().unwrap();
 
@@ -68,6 +70,11 @@ fn main() {
                      .short("m")
                      .long("mine")
                      .help("Starts the debugging mining loop"))
+				.arg(Arg::with_name("wallet_url")
+                     .short("w")
+                     .long("wallet_url")
+                     .help("A listening wallet receiver to which mining rewards will be sent")
+					 .takes_value(true))
                 .arg(Arg::with_name("config")
                      .short("c")
                      .long("config")
@@ -95,6 +102,16 @@ fn main() {
                      .long("pass")
                      .help("Wallet passphrase used to generate the private key seed")
                      .takes_value(true))
+				.arg(Arg::with_name("dir")
+                     .short("d")
+                     .long("dir")
+                     .help("Directory in which to store wallet files (defaults to current directory)")
+                     .takes_value(true))
+				.arg(Arg::with_name("port")
+                     .short("r")
+                     .long("port")
+                     .help("Port on which to run the wallet receiver when in receiver mode")
+                     .takes_value(true))	 	 
                 .subcommand(SubCommand::with_name("receive")
                             .about("Run the wallet in receiving mode. If an input file is provided, will process it, otherwise runs in server mode waiting for send requests.")
                             .arg(Arg::with_name("input")
@@ -154,6 +171,10 @@ fn server_command(server_args: &ArgMatches) {
 	if server_args.is_present("mine") {
 		server_config.mining_config.enable_mining = true;
 	}
+	if let Some(wallet_url) = server_args.value_of("wallet_url") {
+		server_config.mining_config.wallet_receiver_url = wallet_url.to_string();
+	}
+
 	if let Some(seeds) = server_args.values_of("seed") {
 		server_config.seeding_type = grin::Seeding::List(seeds.map(|s| s.to_string()).collect());
 	}
@@ -199,18 +220,35 @@ fn wallet_command(wallet_args: &ArgMatches) {
 	let key = wallet::ExtendedKey::from_seed(&s, &seed[..])
 		.expect("Error deriving extended key from seed.");
 
+	let default_ip = "127.0.0.1";
+	let mut addr = format!("{}:13416", default_ip);
+
+	let mut wallet_config = WalletConfig::default();
+	if let Some(port) = wallet_args.value_of("port") {
+		addr = format!("{}:{}", default_ip, port);
+		wallet_config.api_http_addr = format!("http://{}", addr).to_string();
+	}
+
+	if let Some(dir) = wallet_args.value_of("dir") {
+		wallet_config.data_file_dir = dir.to_string().clone();
+	}
+	
 	match wallet_args.subcommand() {
+		
 		("receive", Some(receive_args)) => {
 			if let Some(f) = receive_args.value_of("input") {
 				let mut file = File::open(f).expect("Unable to open transaction file.");
 				let mut contents = String::new();
 				file.read_to_string(&mut contents).expect("Unable to read transaction file.");
-				wallet::receive_json_tx(&key, contents.as_str()).unwrap();
+				wallet::receive_json_tx(&wallet_config, &key, contents.as_str()).unwrap();
 			} else {
-				info!("Starting the Grin wallet receiving daemon...");
+				info!("Starting the Grin wallet receiving daemon at {}...", wallet_config.api_http_addr);
 				let mut apis = api::ApiServer::new("/v1".to_string());
-				apis.register_endpoint("/receive".to_string(), wallet::WalletReceiver { key: key });
-				apis.start("127.0.0.1:13416").unwrap_or_else(|e| {
+				apis.register_endpoint("/receive".to_string(), wallet::WalletReceiver { 
+					key: key,
+					config: wallet_config
+				});
+				apis.start(addr).unwrap_or_else(|e| {
 					error!("Failed to start Grin wallet receiver: {}.", e);
 				});
 			}
@@ -224,7 +262,7 @@ fn wallet_command(wallet_args: &ArgMatches) {
 			if let Some(d) = send_args.value_of("dest") {
 				dest = d;
 			}
-			wallet::issue_send_tx(&key, amount, dest.to_string()).unwrap();
+			wallet::issue_send_tx(&wallet_config, &key, amount, dest.to_string()).unwrap();
 		}
 		_ => panic!("Unknown wallet command, use 'grin help wallet' for details"),
 	}

wallet/src/checker.rs

@@ -29,7 +29,7 @@ pub fn refresh_outputs(config: &WalletConfig, ext_key: &ExtendedKey) {
 	let secp = secp::Secp256k1::with_caps(secp::ContextFlag::Commit);
 
 	// operate within a lock on wallet data
-	WalletData::with_wallet(|wallet_data| {
+	WalletData::with_wallet(&config.data_file_dir, |wallet_data| {
 
 		// check each output that's not spent
 		for out in &mut wallet_data.outputs {

wallet/src/lib.rs

@@ -38,3 +38,4 @@ mod types;
 pub use extkey::ExtendedKey;
 pub use receiver::{WalletReceiver, receive_json_tx};
 pub use sender::issue_send_tx;
+pub use types::WalletConfig;

wallet/src/receiver.rs

@@ -69,12 +69,13 @@ struct TxWrapper {
 /// Receive an already well formed JSON transaction issuance and finalize the
 /// transaction, adding our receiving output, to broadcast to the rest of the
 /// network.
-pub fn receive_json_tx(ext_key: &ExtendedKey, partial_tx_str: &str) -> Result<(), Error> {
+pub fn receive_json_tx(config: &WalletConfig, ext_key: &ExtendedKey, partial_tx_str: &str) -> Result<(), Error> {
+	
 	let (amount, blinding, partial_tx) = partial_tx_from_json(partial_tx_str)?;
-	let final_tx = receive_transaction(ext_key, amount, blinding, partial_tx)?;
+	let final_tx = receive_transaction(&config, ext_key, amount, blinding, partial_tx)?;
 	let tx_hex = util::to_hex(ser::ser_vec(&final_tx).unwrap());
 
-	let config = WalletConfig::default();
+	
 	let url = format!("{}/v1/pool/push", config.api_http_addr.as_str());
 	api::client::post(url.as_str(), &TxWrapper { tx_hex: tx_hex })?;
 	Ok(())
@@ -98,6 +99,7 @@ pub struct CbData {
 #[derive(Clone)]
 pub struct WalletReceiver {
 	pub key: ExtendedKey,
+	pub config: WalletConfig,
 }
 
 impl ApiEndpoint for WalletReceiver {
@@ -118,7 +120,7 @@ impl ApiEndpoint for WalletReceiver {
 		match op.as_str() {
 			"coinbase" => {
 				let (out, kern) =
-					receive_coinbase(&self.key, input.amount).map_err(|e| {
+					receive_coinbase(&self.config, &self.key, input.amount).map_err(|e| {
 							api::Error::Internal(format!("Error building coinbase: {:?}", e))
 						})?;
 				let out_bin =
@@ -140,11 +142,11 @@ impl ApiEndpoint for WalletReceiver {
 }
 
 /// Build a coinbase output and the corresponding kernel
-fn receive_coinbase(ext_key: &ExtendedKey, amount: u64) -> Result<(Output, TxKernel), Error> {
+fn receive_coinbase(config: &WalletConfig, ext_key: &ExtendedKey, amount: u64) -> Result<(Output, TxKernel), Error> {
 	let secp = secp::Secp256k1::with_caps(secp::ContextFlag::Commit);
 
 	// operate within a lock on wallet data
-	WalletData::with_wallet(|wallet_data| {
+	WalletData::with_wallet(&config.data_file_dir, |wallet_data| {
 
 		// derive a new private for the reward
 		let next_child = wallet_data.next_child(ext_key.fingerprint);
@@ -165,7 +167,8 @@ fn receive_coinbase(ext_key: &ExtendedKey, amount: u64) -> Result<(Output, TxKer
 }
 
 /// Builds a full transaction from the partial one sent to us for transfer
-fn receive_transaction(ext_key: &ExtendedKey,
+fn receive_transaction(config: &WalletConfig,
+					   ext_key: &ExtendedKey,
                        amount: u64,
                        blinding: SecretKey,
                        partial: Transaction)
@@ -174,7 +177,7 @@ fn receive_transaction(ext_key: &ExtendedKey,
 	let secp = secp::Secp256k1::with_caps(secp::ContextFlag::Commit);
 
 	// operate within a lock on wallet data
-	WalletData::with_wallet(|wallet_data| {
+	WalletData::with_wallet(&config.data_file_dir, |wallet_data| {
 
 		let next_child = wallet_data.next_child(ext_key.fingerprint);
 		let out_key = ext_key.derive(&secp, next_child).map_err(|e| Error::Key(e))?;

wallet/src/sender.rs

@@ -25,10 +25,10 @@ use types::*;
 /// wallet
 /// UTXOs. The destination can be "stdout" (for command line) or a URL to the
 /// recipients wallet receiver (to be implemented).
-pub fn issue_send_tx(ext_key: &ExtendedKey, amount: u64, dest: String) -> Result<(), Error> {
+pub fn issue_send_tx(config: &WalletConfig, ext_key: &ExtendedKey, amount: u64, dest: String) -> Result<(), Error> {
 	checker::refresh_outputs(&WalletConfig::default(), ext_key);
 
-	let (tx, blind_sum) = build_send_tx(ext_key, amount)?;
+	let (tx, blind_sum) = build_send_tx(config, ext_key, amount)?;
 	let json_tx = partial_tx_to_json(amount, blind_sum, tx);
 	if dest == "stdout" {
 		println!("{}", json_tx);
@@ -42,12 +42,12 @@ pub fn issue_send_tx(ext_key: &ExtendedKey, amount: u64, dest: String) -> Result
 /// Builds a transaction to send to someone from the HD seed associated with the
 /// wallet and the amount to send. Handles reading through the wallet data file,
 /// selecting outputs to spend and building the change.
-fn build_send_tx(ext_key: &ExtendedKey, amount: u64) -> Result<(Transaction, SecretKey), Error> {
+fn build_send_tx(config: &WalletConfig, ext_key: &ExtendedKey, amount: u64) -> Result<(Transaction, SecretKey), Error> {
 	// first, rebuild the private key from the seed
 	let secp = secp::Secp256k1::with_caps(secp::ContextFlag::Commit);
 
 	// operate within a lock on wallet data
-	WalletData::with_wallet(|wallet_data| {
+	WalletData::with_wallet(&config.data_file_dir, |wallet_data| {
 
 		// second, check from our local wallet data for outputs to spend
 		let (coins, change) = wallet_data.select(ext_key.fingerprint, amount);

wallet/src/types.rs

@@ -17,6 +17,7 @@ use std::fs::{self, File, OpenOptions};
 use std::io::Write;
 use std::num;
 use std::path::Path;
+use std::path::MAIN_SEPARATOR;
 
 use serde_json;
 
@@ -78,11 +79,15 @@ impl From<api::Error> for Error {
 #[derive(Debug, Clone)]
 pub struct WalletConfig {
 	pub api_http_addr: String,
+	pub data_file_dir: String,
 }
 
 impl Default for WalletConfig {
 	fn default() -> WalletConfig {
-		WalletConfig { api_http_addr: "http://127.0.0.1:13415".to_string() }
+		WalletConfig { 
+			api_http_addr: "http://127.0.0.1:13415".to_string(),
+			data_file_dir: ".".to_string(),
+		}
 	}
 }
 
@@ -140,23 +145,31 @@ impl WalletData {
 	/// Note that due to the impossibility to do an actual file lock easily
 	/// across operating systems, this just creates a lock file with a "should
   /// not exist" option.
-	pub fn with_wallet<T, F>(f: F) -> Result<T, Error>
+	pub fn with_wallet<T, F>(data_file_dir:&str, f: F) -> Result<T, Error>
 		where F: FnOnce(&mut WalletData) -> T
 	{
+		//create directory if it doesn't exist
+		fs::create_dir_all(data_file_dir).unwrap_or_else(|why| {
+        	info!("! {:?}", why.kind());
+    	});
+		
+		let data_file_path = &format!("{}{}{}", data_file_dir, MAIN_SEPARATOR, DAT_FILE);
+		let lock_file_path = &format!("{}{}{}", data_file_dir, MAIN_SEPARATOR, LOCK_FILE);
+
 		// create the lock files, if it already exists, will produce an error
-    OpenOptions::new().write(true).create_new(true).open(LOCK_FILE).map_err(|e| {
+    	OpenOptions::new().write(true).create_new(true).open(lock_file_path).map_err(|e| {
 				Error::WalletData(format!("Could not create wallet lock file. Either \
             some other process is using the wallet or there's a write access \
             issue."))
-    })?;
+    	})?;
 
 		// do what needs to be done
-		let mut wdat = WalletData::read_or_create()?;
+		let mut wdat = WalletData::read_or_create(data_file_path)?;
 		let res = f(&mut wdat);
-		wdat.write()?;
+		wdat.write(data_file_path)?;
 
 		// delete the lock file
-		fs::remove_file(LOCK_FILE).map_err(|e| {
+		fs::remove_file(lock_file_path).map_err(|e| {
 				Error::WalletData(format!("Could not remove wallet lock file. Maybe insufficient \
 				                           rights?"))
 			})?;
@@ -165,9 +178,9 @@ impl WalletData {
 	}
 
 	/// Read the wallet data or created a brand new one if it doesn't exist yet
-	fn read_or_create() -> Result<WalletData, Error> {
-		if Path::new(DAT_FILE).exists() {
-			WalletData::read()
+	fn read_or_create(data_file_path:&str) -> Result<WalletData, Error> {
+		if Path::new(data_file_path).exists() {
+			WalletData::read(data_file_path)
 		} else {
 			// just create a new instance, it will get written afterward
 			Ok(WalletData { outputs: vec![] })
@@ -175,21 +188,21 @@ impl WalletData {
 	}
 
 	/// Read the wallet data from disk.
-	fn read() -> Result<WalletData, Error> {
-		let data_file = File::open(DAT_FILE)
-      .map_err(|e| Error::WalletData(format!("Could not open {}: {}", DAT_FILE, e)))?;
+	fn read(data_file_path:&str) -> Result<WalletData, Error> {
+		let data_file = File::open(data_file_path)
+      .map_err(|e| Error::WalletData(format!("Could not open {}: {}", data_file_path, e)))?;
 		serde_json::from_reader(data_file)
-			.map_err(|e| Error::WalletData(format!("Error reading {}: {}", DAT_FILE, e)))
+			.map_err(|e| Error::WalletData(format!("Error reading {}: {}", data_file_path, e)))
 	}
 
 	/// Write the wallet data to disk.
-	fn write(&self) -> Result<(), Error> {
-		let mut data_file = File::create(DAT_FILE)
-      .map_err(|e| Error::WalletData(format!("Could not create {}: {}", DAT_FILE, e)))?;
+	fn write(&self, data_file_path:&str) -> Result<(), Error> {
+		let mut data_file = File::create(data_file_path)
+      .map_err(|e| Error::WalletData(format!("Could not create {}: {}", data_file_path, e)))?;
 		let res_json = serde_json::to_vec_pretty(self)
       .map_err(|_| Error::WalletData(format!("Error serializing wallet data.")))?;
 		data_file.write_all(res_json.as_slice())
-			.map_err(|e| Error::WalletData(format!("Error writing {}: {}", DAT_FILE, e)))
+			.map_err(|e| Error::WalletData(format!("Error writing {}: {}", data_file_path, e)))
 	}
 
 	/// Append a new output information to the wallet data.