Fix the light client protocol protobuf schema (#12732)

* Fix the light client protocol protobuf schema

* Add another test

* Remove unused protobuf struct

* Ok you have to use the nightly rustfmt apparently

substrate/client/network/light/src/schema.rs

@@ -23,3 +23,47 @@ pub(crate) mod v1 {
 		include!(concat!(env!("OUT_DIR"), "/api.v1.light.rs"));
 	}
 }
+
+#[cfg(test)]
+mod tests {
+	use prost::Message as _;
+
+	#[test]
+	fn empty_proof_encodes_correctly() {
+		let encoded = super::v1::light::Response {
+			response: Some(super::v1::light::response::Response::RemoteReadResponse(
+				super::v1::light::RemoteReadResponse { proof: Some(Vec::new()) },
+			)),
+		}
+		.encode_to_vec();
+
+		// Make sure that the response contains one field of number 2 and wire type 2 (message),
+		// then another field of number 2 and wire type 2 (bytes), then a length of 0.
+		assert_eq!(encoded, vec![(2 << 3) | 2, 2, (2 << 3) | 2, 0]);
+	}
+
+	#[test]
+	fn no_proof_encodes_correctly() {
+		let encoded = super::v1::light::Response {
+			response: Some(super::v1::light::response::Response::RemoteReadResponse(
+				super::v1::light::RemoteReadResponse { proof: None },
+			)),
+		}
+		.encode_to_vec();
+
+		// Make sure that the response contains one field of number 2 and wire type 2 (message).
+		assert_eq!(encoded, vec![(2 << 3) | 2, 0]);
+	}
+
+	#[test]
+	fn proof_encodes_correctly() {
+		let encoded = super::v1::light::Response {
+			response: Some(super::v1::light::response::Response::RemoteReadResponse(
+				super::v1::light::RemoteReadResponse { proof: Some(vec![1, 2, 3, 4]) },
+			)),
+		}
+		.encode_to_vec();
+
+		assert_eq!(encoded, vec![(2 << 3) | 2, 6, (2 << 3) | 2, 4, 1, 2, 3, 4]);
+	}
+}