Merge pull request #975 from ava-labs/fix/fee-tolerance

fix: fee tolerance range

Author: rictorlome

src/utils/validateBurnedAmount/validateDynamicBurnedAmount.test.ts

@@ -2,23 +2,14 @@ import { validateDynamicBurnedAmount } from './validateDynamicBurnedAmount';
 import { describe, it, expect } from 'vitest';
 
 describe('validateDynamicBurnedAmount', () => {
-  it('throws an expected error if feeTolerance is less than 1', () => {
+  it('throws an expected error if feeTolerance is less than 0', () => {
     expect(() =>
       validateDynamicBurnedAmount({
         burnedAmount: (280750n * 75n) / 100n, // 25% lower,
         feeAmount: 280750n,
-        feeTolerance: 0.5,
+        feeTolerance: -1,
       }),
-    ).toThrowError('feeTolerance must be [1,100]');
-  });
-  it('throws an expected error if feeTolerance is greater than 100', () => {
-    expect(() =>
-      validateDynamicBurnedAmount({
-        burnedAmount: (280750n * 75n) / 100n, // 25% lower,
-        feeAmount: 280750n,
-        feeTolerance: 101,
-      }),
-    ).toThrowError('feeTolerance must be [1,100]');
+    ).toThrowError('feeTolerance must be be non-negative.');
   });
 
   it('returns false if burned amount is over the tolerance range', () => {
@@ -59,7 +50,7 @@ describe('validateDynamicBurnedAmount', () => {
     const resultHigher = validateDynamicBurnedAmount({
       burnedAmount: (280750n * 125n) / 100n, // 25% higher
       feeAmount: 280750n,
-      feeTolerance: 50.9,
+      feeTolerance: 500.9,
     });
     expect(resultHigher).toStrictEqual({
       isValid: true,

src/utils/validateBurnedAmount/validateDynamicBurnedAmount.ts

@@ -18,12 +18,13 @@ export const validateDynamicBurnedAmount = ({
 }): { isValid: boolean; txFee: bigint } => {
   const feeToleranceInt = Math.floor(feeTolerance);
 
-  if (feeToleranceInt < 1 || feeToleranceInt > 100) {
-    throw new Error('feeTolerance must be [1,100]');
+  if (feeToleranceInt < 0) {
+    throw new Error('feeTolerance must be be non-negative.');
   }
 
-  const min = (feeAmount * (100n - BigInt(feeToleranceInt))) / 100n;
-  const max = (feeAmount * (100n + BigInt(feeToleranceInt))) / 100n;
+  const delta = (feeAmount * BigInt(feeToleranceInt)) / 100n;
+  const min = delta > feeAmount ? 0n : feeAmount - delta;
+  const max = feeAmount + delta;
 
   return {
     isValid: burnedAmount >= min && burnedAmount <= max,