f - Add builds_offer_with_paths test

Author: jkczyz

lightning/src/offers/offer.rs

@@ -44,8 +44,7 @@ pub enum Destination {
 impl OfferBuilder {
 	///
 	pub fn new(description: String, destination: Destination) -> Self {
-		// TODO: Replace with sha256::Hash::all_zeros()
-		let id = sha256::Hash::from_engine(sha256::HashEngine::default());
+		let id = sha256::Hash::all_zeros();
 		let (node_id, paths) = match destination {
 			Destination::NodeId(node_id) => (Some(node_id), None),
 			Destination::Path(path) => (None, Some(vec![path])),
@@ -93,6 +92,12 @@ impl OfferBuilder {
 		self
 	}
 
+	///
+	pub fn path(mut self, path: BlindedPath) -> Self {
+		self.offer.paths.get_or_insert_with(Vec::new).push(path);
+		self
+	}
+
 	///
 	pub fn quantity_fixed(mut self, quantity: NonZeroU64) -> Self {
 		let quantity = Some(quantity.get()).filter(|quantity| *quantity != 1);
@@ -372,7 +377,7 @@ type Empty = ();
 
 #[cfg(test)]
 mod tests {
-	use super::{Amount, Destination, OfferBuilder, SendInvoice, merkle};
+	use super::{Amount, BlindedPath, Destination, OfferBuilder, OnionMessagePath, SendInvoice, merkle};
 
 	use bitcoin::blockdata::constants::genesis_block;
 	use bitcoin::network::constants::Network;
@@ -391,6 +396,15 @@ mod tests {
 		SecretKey::from_slice(&[45; 32]).unwrap()
 	}
 
+	fn blinded_pubkey(byte: u8) -> PublicKey {
+		let secp_ctx = Secp256k1::new();
+		PublicKey::from_secret_key(&secp_ctx, &blinded_privkey(byte))
+	}
+
+	fn blinded_privkey(byte: u8) -> SecretKey {
+		SecretKey::from_slice(&[byte; 32]).unwrap()
+	}
+
 	#[test]
 	fn builds_offer_with_defaults() {
 		let offer = OfferBuilder::new("foo".into(), Destination::NodeId(pubkey())).build();
@@ -403,6 +417,7 @@ mod tests {
 		assert_eq!(offer.features(), None);
 		assert_eq!(offer.absolute_expiry(), None);
 		assert!(!offer.is_expired());
+		assert_eq!(offer.paths(), None);
 		assert_eq!(offer.issuer(), None);
 		assert_eq!(offer.quantity_min(), 1);
 		assert_eq!(offer.quantity_max(), 1);
@@ -538,6 +553,55 @@ mod tests {
 		assert_eq!(offer.as_tlv_stream().absolute_expiry, Some(past_expiry.as_secs().into()));
 	}
 
+	#[test]
+	fn builds_offer_with_paths() {
+		// TODO: Use more realistic data
+		let paths = vec![
+			BlindedPath {
+				blinding: pubkey(),
+				path: vec![
+					OnionMessagePath {
+						node_id: blinded_pubkey(43), encrypted_recipient_data: vec![0; 43],
+					},
+					OnionMessagePath {
+						node_id: blinded_pubkey(44), encrypted_recipient_data: vec![0; 44],
+					},
+				].into(),
+			},
+			BlindedPath {
+				blinding: pubkey(),
+				path: vec![
+					OnionMessagePath {
+						node_id: blinded_pubkey(45), encrypted_recipient_data: vec![0; 45],
+					},
+					OnionMessagePath {
+						node_id: blinded_pubkey(46), encrypted_recipient_data: vec![0; 46],
+					},
+				].into(),
+			},
+		];
+
+		let offer = OfferBuilder::new("foo".into(), Destination::NodeId(pubkey()))
+			.path(paths[0].clone())
+			.path(paths[1].clone())
+			.build();
+		let tlv_stream = offer.as_tlv_stream();
+		assert_eq!(offer.paths(), Some(&paths));
+		assert_eq!(offer.node_id(), pubkey());
+		assert_ne!(pubkey(), blinded_pubkey(44));
+		assert_eq!(tlv_stream.paths, Some((&paths).into()));
+		assert_eq!(tlv_stream.node_id, Some(&pubkey()));
+
+		let offer = OfferBuilder::new("foo".into(), Destination::Path(paths[0].clone()))
+			.path(paths[1].clone())
+			.build();
+		let tlv_stream = offer.as_tlv_stream();
+		assert_eq!(offer.paths(), Some(&paths));
+		assert_eq!(offer.node_id(), blinded_pubkey(44));
+		assert_eq!(tlv_stream.paths, Some((&paths).into()));
+		assert_eq!(tlv_stream.node_id, None);
+	}
+
 	#[test]
 	fn builds_offer_with_issuer() {
 		let offer = OfferBuilder::new("foo".into(), Destination::NodeId(pubkey()))

lightning/src/util/ser.rs

@@ -562,6 +562,9 @@ impl<T: Readable> Readable for WithLength<Vec<T>, u8> {
 		Ok(Self(result, core::marker::PhantomData))
 	}
 }
+impl<T, U> From<Vec<T>> for WithLength<Vec<T>, U> {
+	fn from(v: Vec<T>) -> Self { Self(v, core::marker::PhantomData) }
+}
 
 /// For variable-length values within TLV record where the length is encoded as part of the record.
 /// Used to prevent encoding the length twice.