test: add NumberUtil test case

packages/common/tests/NumberUtil.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import { NumberUtil } from '../src/utils/NumberUtil.js'
+import BigNumber from 'bignumber.js'
 
 // -- Tests --------------------------------------------------------------------
 describe('NumberUtil', () => {
@@ -8,3 +9,39 @@ describe('NumberUtil', () => {
     expect(isGreaterThan).toBe(true)
   })
 })
+
+describe('multiply', () => {
+  it('should return 0 if either value is undefined', () => {
+    expect(NumberUtil.multiply(undefined, '10')).toEqual(new BigNumber(0))
+    expect(NumberUtil.multiply('10', undefined)).toEqual(new BigNumber(0))
+  })
+
+  it('should multiply two numbers represented as strings', () => {
+    const result = NumberUtil.multiply('2', '3')
+    expect(result).toEqual(new BigNumber(6))
+  })
+
+  it('should handle decimals correctly', () => {
+    const result = NumberUtil.multiply('1.5', '2.5')
+    expect(result).toEqual(new BigNumber(3.75))
+  })
+})
+
+describe('formatNumberToLocalString', () => {
+  it('should return "0.00" if value is undefined', () => {
+    expect(NumberUtil.formatNumberToLocalString(undefined)).toBe('0.00')
+  })
+
+  it('should format a number to a local string with specified decimals', () => {
+    expect(NumberUtil.formatNumberToLocalString(1234.5678, 2)).toBe('1,234.57')
+    expect(NumberUtil.formatNumberToLocalString(1234.5, 2)).toBe('1,234.50')
+  })
+
+  it('should format a string representation of a number to a local string', () => {
+    expect(NumberUtil.formatNumberToLocalString('1234.5678', 2)).toBe('1,234.57')
+  })
+
+  it('should handle invalid string input gracefully', () => {
+    expect(NumberUtil.formatNumberToLocalString('invalid', 2)).toBe('NaN')
+  })
+})