add amount tests

packages/types/src/amount.test.ts

@@ -3,10 +3,12 @@ import {
   addAmounts,
   displayAmount,
   displayUsd,
+  divideAmounts,
   fromBaseUnitAmount,
   fromValueView,
   isZero,
   joinLoHiAmount,
+  subtractAmounts,
 } from './amount';
 import { Amount } from '@buf/penumbra-zone_penumbra.bufbuild_es/penumbra/core/num/v1/num_pb';
 import {
@@ -114,6 +116,68 @@ describe('addAmounts', () => {
   });
 });
 
+describe('subtractAmounts', () => {
+  it('should return an Amount with lo and hi equal to 0 when both inputs are 0', () => {
+    const a = new Amount({ lo: 0n, hi: 0n });
+    const b = new Amount({ lo: 0n, hi: 0n });
+
+    const result = subtractAmounts(a, b);
+
+    expect(result.lo).toBe(0n);
+    expect(result.hi).toBe(0n);
+  });
+
+  it('should correctly subtract two Amounts', () => {
+    const a = new Amount({ lo: 2n, hi: 2n });
+    const b = new Amount({ lo: 1n, hi: 1n });
+
+    const result = subtractAmounts(a, b);
+
+    expect(result.lo).toBe(1n);
+    expect(result.hi).toBe(1n);
+  });
+
+  it('should throw an error if minuend is less than subtrahend', () => {
+    const a = new Amount({ lo: 1n, hi: 1n });
+    const b = new Amount({ lo: 2n, hi: 2n });
+
+    expect(() => subtractAmounts(a, b)).toThrow('Amount cannot be negative');
+  });
+});
+
+describe('divideAmounts', () => {
+  it('should throw an error when dividing by zero', () => {
+    const a = new Amount({ lo: 1n, hi: 1n });
+    const b = new Amount({ lo: 0n, hi: 0n });
+
+    expect(() => divideAmounts(a, b)).toThrow('Division by zero');
+  });
+
+  it('should return 0n if dividend is zero', () => {
+    const a = new Amount({ lo: 0n, hi: 0n });
+    const b = new Amount({ lo: 18446744073709551615n, hi: 1n });
+    const result = divideAmounts(a, b);
+
+    expect(result.isZero()).toBeTruthy();
+  });
+
+  it('should return a number without fractions when dividing without remainder', () => {
+    const a = new Amount({ lo: 6n, hi: 0n });
+    const b = new Amount({ lo: 2n, hi: 0n });
+    const result = divideAmounts(a, b);
+
+    expect(result.toNumber()).toBe(3);
+  });
+
+  it('should return a number with specified precision', () => {
+    const a = new Amount({ lo: 10n, hi: 0n });
+    const b = new Amount({ lo: 3n, hi: 0n });
+    const result = divideAmounts(a, b);
+
+    expect(result.toFixed(3)).toEqual('3.333');
+  });
+});
+
 describe('Formatting', () => {
   describe('displayAmount()', () => {
     it('no decimals', () => {

packages/types/src/amount.ts

@@ -33,7 +33,7 @@ export const subtractAmounts = (minuend: Amount, subtrahend: Amount): Amount =>
   const joinedMinuend = joinLoHiAmount(minuend);
   const joinedSubtrahend = joinLoHiAmount(subtrahend);
 
-  if (joinedSubtrahend > joinedMinuend) throw new Error('Amount cannot be negative ');
+  if (joinedSubtrahend > joinedMinuend) throw new Error('Amount cannot be negative');
 
   const joined = joinedMinuend - joinedSubtrahend;
   const { lo, hi } = splitLoHi(joined);
@@ -46,9 +46,7 @@ export const divideAmounts = (dividend: Amount, divider: Amount): BigNumber => {
   const joinedDividend = new BigNumber(joinLoHiAmount(dividend).toString());
   const joinedDivider = new BigNumber(joinLoHiAmount(divider).toString());
 
-  const bigNumber = joinedDividend.dividedBy(joinedDivider);
-  console.log(bigNumber);
-  return bigNumber;
+  return joinedDividend.dividedBy(joinedDivider);
 };
 
 // This function takes a number and formats it in a display-friendly way (en-US locale)