From 0d466fa8d00da2c9686961282a0e4813ec77b6f2 Mon Sep 17 00:00:00 2001
From: Robert Habermeier <rphmeier@gmail.com>
Date: Wed, 14 Dec 2016 20:27:03 +0100
Subject: [PATCH] light: tests for response module

---
 sync/src/light_sync/response.rs | 116 ++++++++++++++++++++++++++++++--
 1 file changed, 111 insertions(+), 5 deletions(-)

diff --git a/sync/src/light_sync/response.rs b/sync/src/light_sync/response.rs
index 2d64bb36b..131f7e4e2 100644
--- a/sync/src/light_sync/response.rs
+++ b/sync/src/light_sync/response.rs
@@ -21,10 +21,10 @@ use std::fmt;
 use ethcore::header::Header;
 use light::request::{HashOrNumber, Headers as HeadersRequest};
 use rlp::{DecoderError, UntrustedRlp, View};
-use util::H256;
+use util::{Bytes, H256};
 
 /// Errors found when decoding headers and verifying with basic constraints.
-#[derive(Debug, Clone)]
+#[derive(Debug, PartialEq)]
 pub enum BasicError {
 	/// Wrong skip value: expected, found (if any).
 	WrongSkip(u64, Option<u64>),
@@ -46,7 +46,7 @@ impl From<DecoderError> for BasicError {
 
 impl fmt::Display for BasicError {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-		write!(f, "Header response verification error: ");
+		try!(write!(f, "Header response verification error: "));
 
 		match *self {
 			BasicError::WrongSkip(ref exp, ref got)
@@ -58,7 +58,7 @@ impl fmt::Display for BasicError {
 			BasicError::TooManyHeaders(ref max, ref got)
 				=> write!(f, "too many headers (max {}, got {})", max, got),
 			BasicError::Decoder(ref err)
-				=> write!(f, "invalid encoding ({})", err),
+				=> write!(f, "{}", err),
 		}
 	}
 }
@@ -73,7 +73,7 @@ pub trait Constraint {
 
 /// Decode a response and do basic verification against a request.
 pub fn decode_and_verify(headers: &[Bytes], request: &HeadersRequest) -> Result<Vec<Header>, BasicError> {
-	let headers: Vec<_> = try!!(headers.iter().map(|x| UntrustedRlp::new(&x).as_val()).collect());
+	let headers: Vec<_> = try!(headers.iter().map(|x| UntrustedRlp::new(&x).as_val()).collect());
 
 	let reverse = request.reverse;
 
@@ -84,6 +84,8 @@ pub fn decode_and_verify(headers: &[Bytes], request: &HeadersRequest) -> Result<
 	}
 
 	try!(SkipsBetween(request.skip).verify(&headers, reverse));
+
+	Ok(headers)
 }
 
 struct StartsAtNumber(u64);
@@ -150,3 +152,107 @@ impl Constraint for Max {
 	}
 }
 
+#[cfg(test)]
+mod tests {
+	use ethcore::header::Header;
+	use light::request::Headers as HeadersRequest;
+
+	use super::*;
+
+	#[test]
+	fn sequential_forward() {
+		let request = HeadersRequest {
+			start: 10.into(),
+			max: 30,
+			skip: 0,
+			reverse: false,
+		};
+
+		let mut parent_hash = None;
+		let headers: Vec<_> = (0..25).map(|x| x + 10).map(|x| {
+			let mut header = Header::default();
+			header.set_number(x);
+
+			if let Some(parent_hash) = parent_hash {
+				header.set_parent_hash(parent_hash);
+			}
+
+			parent_hash = Some(header.hash());
+
+			::rlp::encode(&header).to_vec()
+		}).collect();
+
+		assert!(decode_and_verify(&headers, &request).is_ok());
+	}
+
+	#[test]
+	fn sequential_backward() {
+		let request = HeadersRequest {
+			start: 10.into(),
+			max: 30,
+			skip: 0,
+			reverse: true,
+		};
+
+		let mut parent_hash = None;
+		let headers: Vec<_> = (0..25).map(|x| x + 10).rev().map(|x| {
+			let mut header = Header::default();
+			header.set_number(x);
+
+			if let Some(parent_hash) = parent_hash {
+				header.set_parent_hash(parent_hash);
+			}
+
+			parent_hash = Some(header.hash());
+
+			::rlp::encode(&header).to_vec()
+		}).collect();
+
+		assert!(decode_and_verify(&headers, &request).is_ok());
+	}
+
+	#[test]
+	fn too_many() {
+		let request = HeadersRequest {
+			start: 10.into(),
+			max: 20,
+			skip: 0,
+			reverse: false,
+		};
+
+		let mut parent_hash = None;
+		let headers: Vec<_> = (0..25).map(|x| x + 10).map(|x| {
+			let mut header = Header::default();
+			header.set_number(x);
+
+			if let Some(parent_hash) = parent_hash {
+				header.set_parent_hash(parent_hash);
+			}
+
+			parent_hash = Some(header.hash());
+
+			::rlp::encode(&header).to_vec()
+		}).collect();
+
+		assert_eq!(decode_and_verify(&headers, &request), Err(BasicError::TooManyHeaders(20, 25)));
+	}
+
+	#[test]
+	fn wrong_skip() {
+		let request = HeadersRequest {
+			start: 10.into(),
+			max: 30,
+			skip: 5,
+			reverse: false,
+		};
+
+		let headers: Vec<_> = (0..25).map(|x| x * 3).map(|x| x + 10).map(|x| {
+			let mut header = Header::default();
+			header.set_number(x);
+
+			::rlp::encode(&header).to_vec()
+		}).collect();
+
+		assert_eq!(decode_and_verify(&headers, &request), Err(BasicError::WrongSkip(5, Some(2))));
+	}
+}