Add :height param to balance endpoint and use in test

client/src/lib.rs

@@ -79,6 +79,40 @@ impl SequencerClient {
             Some(block) => block,
             None => self.get_height().await?,
         };
+
+        // As of block zero the state is empty, and the balance will be zero.
+        if block == 0 {
+            return Ok(0.into());
+        }
+
+        // Block is non-zero, we can safely decrement to query the state as of the previous block.
+        block -= 1;
+
+        tracing::debug!(%address, block, "fetching Espresso balance");
+        dbg!(&address, &block);
+
+        let balance = self
+            .0
+            .get::<Option<FeeAmount>>(&format!("fee-state/fee-balance/{block}/{address:#x}"))
+            .send()
+            .await
+            .unwrap()
+            .unwrap();
+
+        Ok(balance)
+    }
+
+    /// Get the balance for a given account at a given block height, defaulting to current balance.
+    pub async fn get_espresso_balance_legacy(
+        &self,
+        address: Address,
+        block: Option<u64>,
+    ) -> anyhow::Result<FeeAmount> {
+        // Get the block height to query at, defaulting to the latest block.
+        let mut block = match block {
+            Some(block) => block,
+            None => self.get_height().await?,
+        };
         // As of block zero the state is empty, and the balance will be zero.
         if block == 0 {
             return Ok(0.into());

sequencer/api/merklized_state.toml

@@ -1,4 +1,5 @@
 [route.getfeebalance]
-PATH = ["fee-balance/latest/:address"]
+PATH = ["fee-balance/:height/:address"]
+":height" = "Integer"
 ":address" = "Literal"
 DOC = "Get current balance in fee state. Expected parameter is an Ethereum address in hex format."

sequencer/src/api/endpoints.rs

@@ -60,18 +60,28 @@ where
     let extension = toml::from_str(include_str!("../../api/merklized_state.toml"))?;
     options.extensions.push(extension);
 
-    let mut api =
-        merklized_state::define_api::<State, SeqTypes, FeeMerkleTree, Ver, 256>(&options)?;
+    let mut api = merklized_state::define_api::<
+        State,
+        SeqTypes,
+        FeeMerkleTree,
+        Ver,
+        { FeeMerkleTree::ARITY },
+    >(&options)?;
 
     api.get("getfeebalance", move |req, state| {
         async move {
             let address = req.string_param("address")?;
-            let height = state.get_last_state_height().await?;
-            let snapshot = Snapshot::Index(height as u64);
+            let height = req.string_param("height")?.parse::<u64>().map_err(|e| {
+                merklized_state::Error::Custom {
+                    message: format!("failed to parse block height: {e}"),
+                    status: StatusCode::BAD_REQUEST,
+                }
+            })?;
+            let snapshot = Snapshot::Index(height);
             let key = address
                 .parse()
-                .map_err(|_| merklized_state::Error::Custom {
-                    message: "failed to parse address".to_string(),
+                .map_err(|e| merklized_state::Error::Custom {
+                    message: format!("failed to parse address: {e}"),
                     status: StatusCode::BAD_REQUEST,
                 })?;
             let path = state.get_path(snapshot, key).await?;