test(core): Test insert displaces conflicting blocks

Author: ValuedMammal

crates/core/src/checkpoint.rs

@@ -364,6 +364,10 @@ impl<D> IntoIterator for CheckPoint<D> {
 mod tests {
     use super::*;
 
+    use alloc::vec::Vec;
+    use bitcoin::consensus::encode::deserialize_hex;
+    use bitcoin::hashes::Hash;
+
     /// Make sure that dropping checkpoints does not result in recursion and stack overflow.
     #[test]
     fn checkpoint_drop_is_not_recursive() {
@@ -422,4 +426,100 @@ mod tests {
             "the checkpoint node should be freed when all strong references are dropped",
         );
     }
+
+    #[test]
+    fn insert_displaces_conflicting_block() {
+        let headers: Vec<Header> = [
+            "0100000000000000000000000000000000000000000000000000000000000000000000003ba3edfd7a7b12b27ac72c3e67768f617fc81bc3888a51323a9fb8aa4b1e5e4adae5494dffff7f2002000000",
+            "0000002006226e46111a0b59caaf126043eb5bbf28c34f3a5e332a1fc7b2b73cf188910f1c96cc459dbb0c7bbc722af14f913da868779290ad48ff87ee314ebb8ae08f384b166069ffff7f2001000000",
+            "0000002078ce518c7dcfd99ad5859c35bd2be15794c0e5dc8e60c1fea3b0461c45da181ca80f828504f88c645ea46cfcf93156269807e3bd409e1317271a1546d238e9b24c166069ffff7f2001000000",
+            "000000200dfd6c5af6ea3cb341a08db344f93743d94b630d122867faff855f6310e58864e6e0c859fda703d66d051b86f16f09b0cead182f3cbe13767cd91b6371ec252c4c166069ffff7f2000000000",
+        ]
+        .into_iter()
+        .map(|s| deserialize_hex::<Header>(s).expect("failed to deserialize header"))
+        .collect();
+
+        let header_0 = headers[0];
+        let header_1 = headers[1];
+        let header_2 = headers[2];
+        let header_3 = headers[3];
+
+        // Test: Insert 2' that conflicts at heights 1, 2.
+        // tip    [0, 1, 2, 3]
+        // insert [1', 2']
+        // new    [0, 2'] (1 is displaced, 3 is evicted)
+        let mut cp = CheckPoint::new(0, header_0);
+        cp = cp.push(1, header_1).unwrap();
+        cp = cp.push(2, header_2).unwrap();
+        cp = cp.push(3, header_3).unwrap();
+
+        let mut header_2_alt = header_2;
+        header_2_alt.prev_blockhash = BlockHash::all_zeros();
+        cp = cp.insert(2, header_2_alt);
+
+        assert_eq!(cp.iter().count(), 2);
+        assert_eq!(cp.height(), 2);
+        assert_eq!(cp.hash(), header_2_alt.block_hash());
+
+        // Test: Insert 3' that conflicts at height 2
+        // tip    [0, 1, 2]
+        // insert [2', 3']
+        // new    [0, 1, 3'] (2 is displaced)
+        let mut cp = CheckPoint::new(0, header_0);
+        cp = cp.push(1, header_1).unwrap();
+        cp = cp.push(2, header_2).unwrap();
+
+        let mut header_3_alt = header_3;
+        header_3_alt.prev_blockhash = BlockHash::all_zeros();
+        cp = cp.insert(3, header_3_alt);
+
+        assert_eq!(cp.iter().count(), 3);
+        assert_eq!(cp.height(), 3);
+        assert_eq!(cp.hash(), header_3_alt.block_hash());
+
+        // Test: Insert 1' that conflicts at height 1
+        // tip    [0, 1, 2, 3]
+        // insert [1']
+        // new    [0, 1'] (2 and 3 are evicted)
+        let mut cp = CheckPoint::new(0, header_0);
+        cp = cp.push(1, header_1).unwrap();
+        cp = cp.push(2, header_2).unwrap();
+        cp = cp.push(3, header_3).unwrap();
+
+        // Create a conflicting block at height 1 with different hash
+        // header_2 expects header_1.block_hash() as its prev_blockhash, but we'll insert a
+        // different block
+        let mut header_1_alt = header_1;
+        header_1_alt.nonce = 13;
+        cp = cp.insert(1, header_1_alt);
+
+        // Verify only genesis and the new block at height 1 remain
+        assert_eq!(cp.iter().count(), 2);
+        assert_eq!(cp.height(), 1);
+        assert_eq!(cp.hash(), header_1_alt.block_hash());
+    }
+
+    #[should_panic(expected = "cannot replace the genesis block")]
+    #[test]
+    fn insert_should_not_displace_genesis() {
+        let headers: Vec<Header> = [
+            "0100000000000000000000000000000000000000000000000000000000000000000000003ba3edfd7a7b12b27ac72c3e67768f617fc81bc3888a51323a9fb8aa4b1e5e4adae5494dffff7f2002000000",
+            "0000002006226e46111a0b59caaf126043eb5bbf28c34f3a5e332a1fc7b2b73cf188910f1c96cc459dbb0c7bbc722af14f913da868779290ad48ff87ee314ebb8ae08f384b166069ffff7f2001000000",
+            "0000002078ce518c7dcfd99ad5859c35bd2be15794c0e5dc8e60c1fea3b0461c45da181ca80f828504f88c645ea46cfcf93156269807e3bd409e1317271a1546d238e9b24c166069ffff7f2001000000",
+        ]
+        .into_iter()
+        .map(|s| deserialize_hex::<Header>(s).expect("failed to deserialize header"))
+        .collect();
+
+        let header_0 = headers[0];
+        let header_1 = headers[1];
+        let header_2 = headers[2];
+
+        // Test: Insert 1' that conflicts at heights 0, 1.
+        // tip    [0, 1]
+        // insert [0', 1']
+        let mut cp = CheckPoint::new(0, header_0);
+        cp = cp.push(1, header_1).unwrap();
+        let _cp = cp.insert(1, header_2);
+    }
 }