feat: Sort descending in FindTransactions query

Signed-off-by: Dmitry Murzin <diralik@yandex.ru>

crates/iroha/tests/queries/mod.rs

@@ -31,3 +31,44 @@ fn too_big_fetch_size_is_not_allowed() {
         ))
     ));
 }
+
+#[test]
+fn find_blocks_reversed() -> eyre::Result<()> {
+    let (network, _rt) = NetworkBuilder::new().start_blocking()?;
+    let client = network.client();
+
+    client.submit_blocking(Register::domain(Domain::new("domain1".parse()?)))?;
+
+    let blocks = client.query(FindBlocks).execute_all()?;
+    assert_eq!(blocks.len(), 2);
+    assert_eq!(blocks[1].header().prev_block_hash, None);
+    assert_eq!(
+        blocks[0].header().prev_block_hash,
+        Some(blocks[1].header().hash())
+    );
+
+    Ok(())
+}
+
+#[test]
+fn find_transactions_reversed() -> eyre::Result<()> {
+    let (network, _rt) = NetworkBuilder::new().start_blocking()?;
+    let client = network.client();
+
+    let register_domain = Register::domain(Domain::new("domain1".parse()?));
+    client.submit_blocking(register_domain.clone())?;
+
+    let txs = client.query(FindTransactions).execute_all()?;
+
+    // check that latest transaction is register domain
+    let Executable::Instructions(instructions) = txs[0].transaction.value.instructions() else {
+        panic!("Expected instructions");
+    };
+    assert_eq!(instructions.len(), 1);
+    assert_eq!(
+        instructions[0],
+        InstructionBox::Register(register_domain.into())
+    );
+
+    Ok(())
+}

crates/iroha/tests/tx_history.rs

@@ -48,16 +48,18 @@ fn client_has_rejected_and_accepted_txs_should_return_tx_history() -> Result<()>
         .execute_all()?;
     assert_eq!(transactions.len(), 50);
 
-    let mut prev_creation_time = core::time::Duration::from_millis(0);
+    let mut prev_creation_time = None;
     transactions
         .iter()
         .map(AsRef::as_ref)
         .map(AsRef::as_ref)
         .for_each(|tx| {
             assert_eq!(tx.authority(), &account_id);
-            //check sorted
-            assert!(tx.creation_time() >= prev_creation_time);
-            prev_creation_time = tx.creation_time();
+            //check sorted descending
+            if let Some(prev_creation_time) = prev_creation_time {
+                assert!(tx.creation_time() <= prev_creation_time);
+            }
+            prev_creation_time = Some(tx.creation_time());
         });
     Ok(())
 }

crates/iroha_core/src/smartcontracts/isi/tx.rs

@@ -22,24 +22,24 @@ use nonzero_ext::nonzero;
 use super::*;
 use crate::smartcontracts::ValidQuery;
 
+/// Iterates transactions of a block in reverse order
 pub(crate) struct BlockTransactionIter(Arc<SignedBlock>, usize);
 pub(crate) struct BlockTransactionRef(Arc<SignedBlock>, usize);
 
 impl BlockTransactionIter {
     fn new(block: Arc<SignedBlock>) -> Self {
-        Self(block, 0)
+        let n_transactions = block.transactions().len();
+        Self(block, n_transactions)
     }
 }
 
 impl Iterator for BlockTransactionIter {
     type Item = BlockTransactionRef;
 
     fn next(&mut self) -> Option<Self::Item> {
-        if self.1 < self.0.transactions().len() {
-            let res = Some(BlockTransactionRef(Arc::clone(&self.0), self.1));
-
-            self.1 += 1;
-            return res;
+        if self.1 != 0 {
+            self.1 -= 1;
+            return Some(BlockTransactionRef(Arc::clone(&self.0), self.1));
         }
 
         None
@@ -69,6 +69,7 @@ impl ValidQuery for FindTransactions {
     ) -> Result<impl Iterator<Item = Self::Item>, QueryExecutionFail> {
         Ok(state_ro
             .all_blocks(nonzero!(1_usize))
+            .rev()
             .flat_map(BlockTransactionIter::new)
             .map(|tx| TransactionQueryOutput {
                 block_hash: tx.block_hash(),