improve(validateRunningBalances): Add expected excesses map (#1500)

Useful to keep this script scalable is to keep track of known excesses produced by anyone sending tokens directly to the Spokes. These excesses can't be easily removed without admin intervention so we shouldn't have the script error out because of them.

src/scripts/validateRunningBalances.ts

@@ -51,6 +51,10 @@ let logger: winston.Logger;
 
 const slowRootCache = {};
 
+const expectedExcesses: { [chainId: number]: { [token: string]: number } } = {
+  [10]: { ["USDC"]: 15.336508 }, // On May 4th, USDC was sent to the SpokePool here: https://optimistic.etherscan.io/tx/0x5f53293fe6a27ff9897d4dde445fd6aab46f841ca641befea48beef62014a549
+};
+
 export async function runScript(_logger: winston.Logger, baseSigner: Signer): Promise<void> {
   logger = _logger;
 
@@ -367,14 +371,17 @@ export async function runScript(_logger: winston.Logger, baseSigner: Signer): Pr
   logger.debug({
     at: "validateRunningBalances#index",
     message: "Historical excesses",
+    expectedExcesses,
     excesses,
   });
-  const unexpectedExcess = Object.entries(excesses).some(([, tokenExcesses]) => {
-    return Object.entries(tokenExcesses).some(([, excesses]) => {
+  const unexpectedExcess = Object.entries(excesses).some(([chainId, tokenExcesses]) => {
+    return Object.entries(tokenExcesses).some(([l1Token, excesses]) => {
       // We only care about the latest excess, because sometimes excesses can appear in historical bundles
       // due to ordering of executing leaves. As long as the excess resets back to 0 eventually it is fine.
       const excess = Number(excesses[0]);
-      return excess > 0.05 || excess < -0.05;
+      // Subtract any expected excesses
+      const excessForChain = excess - (expectedExcesses[chainId]?.[l1Token] ?? 0);
+      return excessForChain > 0.05 || excessForChain < -0.05;
     });
   });
   if (unexpectedExcess) {