f constant-ify the err string

Author: TheBlueMatt

lightning/src/routing/network_graph.rs

@@ -2434,8 +2434,7 @@ mod benches {
 
 	#[bench]
 	fn read_network_graph(bench: &mut Bencher) {
-		let mut d = ::routing::router::test_utils::get_route_file()
-			.expect("Please fetch https://bitcoin.ninja/ldk-net_graph-45d86ead641d-2021-05-27.bin and place it at lightning/net_graph-2021-05-27.bin");
+		let mut d = ::routing::router::test_utils::get_route_file().unwrap();
 		let mut v = Vec::new();
 		d.read_to_end(&mut v).unwrap();
 		bench.iter(|| {
@@ -2445,8 +2444,7 @@ mod benches {
 
 	#[bench]
 	fn write_network_graph(bench: &mut Bencher) {
-		let mut d = ::routing::router::test_utils::get_route_file()
-			.expect("Please fetch https://bitcoin.ninja/ldk-net_graph-45d86ead641d-2021-05-27.bin and place it at lightning/net_graph-2021-05-27.bin");
+		let mut d = ::routing::router::test_utils::get_route_file().unwrap();
 		let net_graph = NetworkGraph::read(&mut d).unwrap();
 		bench.iter(|| {
 			let _ = net_graph.encode();

lightning/src/routing/router.rs

@@ -3869,8 +3869,8 @@ mod tests {
 	fn generate_routes() {
 		let mut d = match super::test_utils::get_route_file() {
 			Ok(f) => f,
-			Err(_) => {
-				eprintln!("Please fetch https://bitcoin.ninja/ldk-net_graph-45d86ead641d-2021-05-27.bin and place it at lightning/net_graph-2021-05-27.bin");
+			Err(e) => {
+				eprintln!("{}", e);
 				return;
 			},
 		};
@@ -3896,8 +3896,8 @@ mod tests {
 	fn generate_routes_mpp() {
 		let mut d = match super::test_utils::get_route_file() {
 			Ok(f) => f,
-			Err(_) => {
-				eprintln!("Please fetch https://bitcoin.ninja/ldk-net_graph-45d86ead641d-2021-05-27.bin and place it at lightning/net_graph-2021-05-27.bin");
+			Err(e) => {
+				eprintln!("{}", e);
 				return;
 			},
 		};
@@ -3924,7 +3924,7 @@ mod tests {
 pub(crate) mod test_utils {
 	use std::fs::File;
 	/// Tries to open a network graph file, or panics with a URL to fetch it.
-	pub(crate) fn get_route_file() -> Result<std::fs::File, std::io::Error> {
+	pub(crate) fn get_route_file() -> Result<std::fs::File, &'static str> {
 		let res = File::open("net_graph-2021-05-27.bin") // By default we're run in RL/lightning
 			.or_else(|_| File::open("lightning/net_graph-2021-05-27.bin")) // We may be run manually in RL/
 			.or_else(|_| { // Fall back to guessing based on the binary location
@@ -3938,9 +3938,10 @@ pub(crate) mod test_utils {
 				path.push("net_graph-2021-05-27.bin");
 				eprintln!("{}", path.to_str().unwrap());
 				File::open(path)
-			});
+			})
+		.map_err(|_| "Please fetch https://bitcoin.ninja/ldk-net_graph-45d86ead641d-2021-05-27.bin and place it at lightning/net_graph-2021-05-27.bin");
 		#[cfg(require_route_graph_test)]
-		return Ok(res.expect("Didn't have route graph and was configured to require it"));
+		return Ok(res.unwrap())
 		#[cfg(not(require_route_graph_test))]
 		return res;
 	}
@@ -3961,8 +3962,7 @@ mod benches {
 
 	#[bench]
 	fn generate_routes(bench: &mut Bencher) {
-		let mut d = test_utils::get_route_file()
-			.expect("Please fetch https://bitcoin.ninja/ldk-net_graph-45d86ead641d-2021-05-27.bin and place it at lightning/net_graph-2021-05-27.bin");
+		let mut d = test_utils::get_route_file().unwrap();
 		let graph = NetworkGraph::read(&mut d).unwrap();
 
 		// First, get 100 (source, destination) pairs for which route-getting actually succeeds...
@@ -3993,8 +3993,7 @@ mod benches {
 
 	#[bench]
 	fn generate_mpp_routes(bench: &mut Bencher) {
-		let mut d = test_utils::get_route_file()
-			.expect("Please fetch https://bitcoin.ninja/ldk-net_graph-45d86ead641d-2021-05-27.bin and place it at lightning/net_graph-2021-05-27.bin");
+		let mut d = test_utils::get_route_file().unwrap();
 		let graph = NetworkGraph::read(&mut d).unwrap();
 
 		// First, get 100 (source, destination) pairs for which route-getting actually succeeds...