Honor configured epoch depth in fee history

crates/anvil/src/eth/api.rs

@@ -1702,16 +1702,7 @@ impl EthApi {
         node_info!("eth_feeHistory");
         // max number of blocks in the requested range
 
-        let current = self.backend.best_number();
-        let slots_in_an_epoch = 32u64;
-
-        let number = match newest_block {
-            BlockNumber::Latest | BlockNumber::Pending => current,
-            BlockNumber::Earliest => 0,
-            BlockNumber::Number(n) => n,
-            BlockNumber::Safe => current.saturating_sub(slots_in_an_epoch),
-            BlockNumber::Finalized => current.saturating_sub(slots_in_an_epoch * 2),
-        };
+        let number = self.backend.convert_block_number(Some(newest_block));
 
         // check if the number predates the fork, if in fork mode
         if let Some(fork) = self.get_fork() {

crates/anvil/tests/it/gas.rs

@@ -4,7 +4,7 @@ use crate::utils::http_provider_with_signer;
 use alloy_network::{EthereumWallet, TransactionBuilder};
 use alloy_primitives::{Address, U64, U256, uint};
 use alloy_provider::Provider;
-use alloy_rpc_types::{BlockId, TransactionRequest};
+use alloy_rpc_types::{BlockId, BlockNumberOrTag, TransactionRequest};
 use alloy_serde::WithOtherFields;
 use anvil::{NodeConfig, eth::fees::INITIAL_BASE_FEE, spawn};
 
@@ -233,6 +233,25 @@ async fn test_can_use_fee_history() {
     }
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn test_fee_history_safe_finalized_use_slots_in_an_epoch() {
+    let (api, handle) = spawn(NodeConfig::test().with_slots_in_an_epoch(3)).await;
+    let provider = handle.http_provider();
+
+    // (blocks mined, expected safe, expected finalized); finalized saturates at genesis first
+    for (mined, safe, finalized) in [(4, 1, 0), (10, 7, 4)] {
+        while api.block_number().unwrap() < U256::from(mined) {
+            api.mine_one().await;
+        }
+        for (tag, expected) in
+            [(BlockNumberOrTag::Safe, safe), (BlockNumberOrTag::Finalized, finalized)]
+        {
+            let history = provider.get_fee_history(1, tag, &[]).await.unwrap();
+            assert_eq!(history.oldest_block, expected, "{tag} at block {mined}");
+        }
+    }
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn test_estimate_gas_empty_data() {
     let (api, handle) = spawn(NodeConfig::test()).await;