f - special case Quantity::Max(1) in builder

Author: jkczyz

lightning/src/offers/offer.rs

@@ -163,7 +163,10 @@ impl OfferBuilder {
 	///
 	/// Successive calls to this method will override the previous setting.
 	pub fn supported_quantity(mut self, quantity: Quantity) -> Self {
-		self.offer.supported_quantity = quantity;
+		self.offer.supported_quantity = match quantity {
+			Quantity::Max(n) if n.get() == 1 => Quantity::One,
+			_ => quantity,
+		};
 		self
 	}
 
@@ -658,6 +661,7 @@ mod tests {
 
 	#[test]
 	fn builds_offer_with_supported_quantity() {
+		let one = NonZeroU64::new(1).unwrap();
 		let ten = NonZeroU64::new(10).unwrap();
 
 		let offer = OfferBuilder::new("foo".into(), pubkey(42))
@@ -692,5 +696,14 @@ mod tests {
 		let tlv_stream = offer.as_tlv_stream();
 		assert_eq!(offer.supported_quantity(), Quantity::One);
 		assert_eq!(tlv_stream.quantity_max, None);
+
+		let offer = OfferBuilder::new("foo".into(), pubkey(42))
+			.supported_quantity(Quantity::Max(one))
+			.build()
+			.unwrap();
+		let tlv_stream = offer.as_tlv_stream();
+		assert_eq!(offer.supported_quantity(), Quantity::One);
+		assert_eq!(tlv_stream.quantity_max, None);
+
 	}
 }