From 14667bfad6e2dc9ab5152e1356a63e5beb404b86 Mon Sep 17 00:00:00 2001
From: Antioch Peverell <30642645+antiochp@users.noreply.github.com>
Date: Tue, 26 Jun 2018 09:42:12 -0400
Subject: [PATCH] cleanup path fn and add test coverage (#1201)

---
 core/src/core/pmmr.rs | 9 +++------
 core/tests/pmmr.rs    | 8 ++++++++
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/core/src/core/pmmr.rs b/core/src/core/pmmr.rs
index eb96c2c6..b4b77518 100644
--- a/core/src/core/pmmr.rs
+++ b/core/src/core/pmmr.rs
@@ -712,14 +712,11 @@ pub fn is_left_sibling(pos: u64) -> bool {
 /// The size (and therefore the set of peaks) of the MMR
 /// is defined by last_pos.
 pub fn path(pos: u64, last_pos: u64) -> Vec<u64> {
-	let mut path = vec![pos];
+	let mut path = vec![];
 	let mut current = pos;
-	while current + 1 <= last_pos {
+	while current <= last_pos {
+		path.push(current);
 		let (parent, _) = family(current);
-		if parent > last_pos {
-			break;
-		}
-		path.push(parent);
 		current = parent;
 	}
 	path
diff --git a/core/tests/pmmr.rs b/core/tests/pmmr.rs
index 7538cd6e..da6ef633 100644
--- a/core/tests/pmmr.rs
+++ b/core/tests/pmmr.rs
@@ -97,6 +97,14 @@ fn various_families() {
 	assert_eq!(pmmr::family(1_000), (1_001, 997));
 }
 
+#[test]
+fn test_paths() {
+	assert_eq!(pmmr::path(1, 1), [1]);
+	assert_eq!(pmmr::path(1, 3), [1, 3]);
+	assert_eq!(pmmr::path(2, 3), [2, 3]);
+	assert_eq!(pmmr::path(4, 16), [4, 6, 7, 15]);
+}
+
 #[test]
 fn test_is_left_sibling() {
 	assert_eq!(pmmr::is_left_sibling(1), true);