test(trie): witness empty root node

crates/trie/db/tests/witness.rs

@@ -0,0 +1,47 @@
+use alloy_rlp::EMPTY_STRING_CODE;
+use reth_primitives::{constants::EMPTY_ROOT_HASH, keccak256, Account, Address, Bytes, B256, U256};
+use reth_provider::{test_utils::create_test_provider_factory, HashingWriter};
+use reth_trie::{proof::Proof, witness::TrieWitness, HashedPostState, HashedStorage, StateRoot};
+use reth_trie_db::{DatabaseProof, DatabaseStateRoot, DatabaseTrieWitness};
+use std::collections::{HashMap, HashSet};
+
+#[test]
+fn includes_empty_node_preimage() {
+    let factory = create_test_provider_factory();
+    let provider = factory.provider_rw().unwrap();
+
+    // witness includes empty state trie root node
+    assert_eq!(
+        TrieWitness::from_tx(provider.tx_ref()).compute(HashedPostState::default()).unwrap(),
+        HashMap::from([(EMPTY_ROOT_HASH, Bytes::from([EMPTY_STRING_CODE]))])
+    );
+
+    let address = Address::random();
+    let hashed_address = keccak256(address);
+    let hashed_slot = B256::random();
+
+    // Insert account into database
+    provider.insert_account_for_hashing([(address, Some(Account::default()))]).unwrap();
+
+    let state_root = StateRoot::from_tx(provider.tx_ref()).root().unwrap();
+    let multiproof = Proof::from_tx(provider.tx_ref())
+        .with_target((hashed_address, HashSet::from([hashed_slot])))
+        .multiproof()
+        .unwrap();
+
+    let witness = TrieWitness::from_tx(provider.tx_ref())
+        .compute(HashedPostState {
+            accounts: HashMap::from([(hashed_address, Some(Account::default()))]),
+            storages: HashMap::from([(
+                hashed_address,
+                HashedStorage::from_iter(false, [(hashed_slot, U256::ZERO)]),
+            )]),
+        })
+        .unwrap();
+    assert!(witness.contains_key(&state_root));
+    for node in multiproof.account_subtree.values() {
+        assert_eq!(witness.get(&keccak256(&node)), Some(node));
+    }
+    // witness includes empty state trie root node
+    assert_eq!(witness.get(&EMPTY_ROOT_HASH), Some(&Bytes::from([EMPTY_STRING_CODE])));
+}