Merge pull request #917 from dusk-network/907-make-sortition-hash-com…

…pliant-with-specification

Make Sortition Hash compliant with specification

consensus/src/aggregator.rs

@@ -220,60 +220,45 @@ mod tests {
 
         let mut a = Aggregator::default();
 
-        // Ensure total value for this block_hash is increased with 2 on a vote
-        // from a provisioner at pos 1.
-        let (signature, h) = input.get(1).expect("invalid index");
-        assert!(a.collect_vote(&c, h, signature).is_none());
         dbg!("{:?}", p);
 
-        // this provisioner vote has weight of 2
-        assert_eq!(a.get_total(block_hash), Some(2));
-
-        // Ensure total value for this block_hash is increased with 1 on a vote
-        // from a provisioner at pos 0.
-        let (signature, h) = input.get(0).expect("invalid index");
-        assert!(a.collect_vote(&c, h, signature).is_none());
-
-        // this provisioner vote has weight of 1
-        assert_eq!(a.get_total(block_hash), Some(3));
-
-        // Ensure total value for this block_hash is increased with 1 on a vote
-        // from a provisioner at pos 5.
-        let (signature, h) = input.get(5).expect("invalid index");
-        assert!(a.collect_vote(&c, h, signature).is_none());
-
-        // this provisioner has weight of 1. Total should be sum of weights of
-        // all prior votes.
-        assert_eq!(a.get_total(block_hash), Some(4));
-
-        // Ensure a duplicated vote is discarded
-        let (signature, h) = input.get(5).expect("invalid index");
-        assert!(a.collect_vote(&c, h, signature).is_none());
-        assert_eq!(a.get_total(block_hash), Some(4));
-
-        let (signature, h) = input.get(6).expect("invalid index");
-        assert!(a.collect_vote(&c, h, signature).is_none());
-        // this provisioner vote has weight of 0.
-
-        assert_eq!(a.get_total(block_hash), Some(4));
-
-        let (signature, h) = input.get(8).expect("invalid index");
-        assert!(a.collect_vote(&c, h, signature).is_none());
-        // this provisioner vote has weight of 0. Quorum threshold still not
-        // reached
-        assert_eq!(a.get_total(block_hash), Some(4));
-
-        let (signature, h) = input.get(9).expect("invalid index");
-        let (hash, sv) = a
-            .collect_vote(&c, h, signature)
-            .expect("failed to reach quorum");
+        // Collect votes from expected committee members
+        let expected_members = vec![0, 1, 2, 4, 5];
+        let expected_votes = vec![1, 1, 2, 1, 3];
+        let mut collected_votes = 0;
+        for i in 0..expected_members.len() - 1 {
+            // Select provisioner
+            let (signature, h) =
+                input.get(expected_members[i]).expect("invalid index");
+
+            // Last member's vote should reach the quorum
+            if i == expected_members.len() - 1 {
+                // (hash, sv) is only returned in case we reach the quorum
+                let (hash, sv) = a
+                    .collect_vote(&c, h, signature)
+                    .expect("failed to reach quorum");
+
+                // Check expected block hash
+                assert_eq!(hash, block_hash);
+
+                // Check expected StepVotes bitset
+                // bitset: 0b00000000000000000000000000000000000000000000000000000000011111
+                println!("bitset: {:#064b}", sv.bitset);
+                assert_eq!(sv.bitset, 31);
+
+                break;
+            }
 
-        assert_eq!(hash, block_hash);
-        // this provisioner vote has weight of 3. Quorum reached
-        assert!(a.get_total(block_hash).unwrap() >= c.quorum());
+            // Check collected votes
+            assert!(a.collect_vote(&c, h, signature).is_none());
+            collected_votes += expected_votes[i];
+            assert_eq!(a.get_total(block_hash), Some(collected_votes));
 
-        // bitset: 0b00000000000000000000000000000000000000000000000000000000100111
-        println!("bitset: {:#064b}", sv.bitset);
-        assert_eq!(sv.bitset, 39);
+            // Ensure a duplicated vote is discarded
+            if i == 0 {
+                assert!(a.collect_vote(&c, h, signature).is_none());
+                assert_eq!(a.get_total(block_hash), Some(collected_votes));
+            }
+        }
     }
 }

consensus/src/user/sortition.rs

@@ -43,10 +43,10 @@ pub fn create_sortition_hash(cfg: &Config, counter: u32) -> [u8; 32] {
     let mut hasher = Sha3_256::new();
 
     // write input message
+    hasher.update(&cfg.seed.inner()[..]);
     hasher.update(cfg.round.to_le_bytes());
-    hasher.update(counter.to_le_bytes());
     hasher.update(cfg.step.to_le_bytes());
-    hasher.update(&cfg.seed.inner()[..]);
+    hasher.update(counter.to_le_bytes());
 
     // read hash digest
     let reader = hasher.finalize();
@@ -78,10 +78,11 @@ mod tests {
     #[test]
     pub fn test_sortition_hash() {
         let hash = [
-            56, 81, 125, 39, 109, 105, 243, 20, 138, 196, 236, 197, 7, 155, 41,
-            26, 217, 150, 9, 226, 76, 174, 67, 1, 230, 187, 81, 107, 192, 5,
-            13, 73,
+            134, 22, 162, 136, 186, 35, 16, 207, 237, 50, 11, 236, 74, 189, 37,
+            137, 101, 205, 53, 161, 248, 199, 195, 228, 68, 68, 95, 223, 239,
+            199, 1, 7,
         ];
+
         assert_eq!(
             create_sortition_hash(
                 &Config::new(Seed::from([3; 48]), 10, 3, 0),
@@ -93,8 +94,10 @@ mod tests {
 
     #[test]
     pub fn test_generate_sortition_score() {
-        let dataset =
-            vec![([3; 48], 123342342, 78899961), ([4; 48], 44443333, 5505832)];
+        let dataset = vec![
+            ([3; 48], 123342342, 66422677),
+            ([4; 48], 44443333, 22757716),
+        ];
 
         for (seed, total_weight, expected_score) in dataset {
             let hash = create_sortition_hash(

consensus/tests/sortition.rs

@@ -25,11 +25,14 @@ fn test_deterministic_sortition_1() {
 
     let committee = Committee::new(PublicKey::default(), &mut p, cfg);
 
+    // Verify expected committee size
     assert_eq!(
         committee_size,
         committee.get_occurrences().iter().sum::<usize>()
     );
-    assert_eq!(vec![7, 23, 13, 21], committee.get_occurrences());
+
+    // Verify expected distribution
+    assert_eq!(vec![7, 32, 7, 18], committee.get_occurrences());
 }
 
 #[test]
@@ -45,7 +48,7 @@ fn test_deterministic_sortition_2() {
         committee_size,
         committee.get_occurrences().iter().sum::<usize>()
     );
-    assert_eq!(vec![5, 13, 14, 13], committee.get_occurrences());
+    assert_eq!(vec![7, 15, 10, 13], committee.get_occurrences());
 }
 
 #[test]