Add date unit tests

src/client/utils/__test__/date.test.js

@@ -1,6 +1,14 @@
 import {
+  addDays,
+  areDatesEqual,
+  subtractYears,
+  subtractMonths,
+  getStartOfMonth,
+  getRandomDateInRange,
+  isWithinLastTwelveMonths,
   convertDateToFieldDateObject,
   convertDateToFieldShortDateObject,
+  getStartDateOfTwelveMonthsAgo,
 } from '../date'
 
 describe('convertDateToFieldShortDateObject', () => {
@@ -48,3 +56,76 @@ describe('convertDateToFieldDateObject', () => {
     })
   })
 })
+
+describe('getStartDateOfTwelveMonthsAgo', () => {
+  it(
+    'should return a date that is 12 months ago from the current ' +
+      'date and includes the 1st of the month',
+    () => {
+      const today = new Date()
+      const expectedDate = subtractMonths(getStartOfMonth(today), 12)
+      const actualDate = getStartDateOfTwelveMonthsAgo()
+      expect(areDatesEqual(actualDate, expectedDate)).to.equal(true)
+    }
+  )
+})
+
+describe('isWithinLastTwelveMonths', () => {
+  const twelveMonthsAgo = getStartDateOfTwelveMonthsAgo()
+  const twelveMonthsAgoAddOneDay = addDays(new Date(twelveMonthsAgo), 1)
+  const twelveMonthsAgoSubOneDay = subtractYears(new Date(twelveMonthsAgo), 1)
+  const today = new Date()
+  const tomorrow = addDays(today, 1)
+  const yesterday = subtractYears(today, 1)
+
+  it('should be valid for the 1st of the month twelve months ago', () => {
+    expect(isWithinLastTwelveMonths(twelveMonthsAgo)).to.equal(true)
+  })
+
+  it('should be valid for the 2nd of the month twelve months ago', () => {
+    expect(isWithinLastTwelveMonths(twelveMonthsAgoAddOneDay)).to.equal(true)
+  })
+
+  it('should be invalid one day before the 1st of the month, thirteen months ago', () => {
+    expect(isWithinLastTwelveMonths(twelveMonthsAgoSubOneDay)).to.equal(false)
+  })
+
+  it('should be valid for today', () => {
+    expect(isWithinLastTwelveMonths(today)).to.equal(true)
+  })
+
+  it('should be invalid for tomorrow', () => {
+    expect(isWithinLastTwelveMonths(tomorrow)).to.equal(false)
+  })
+
+  it('should be valid for yesterday', () => {
+    expect(isWithinLastTwelveMonths(yesterday)).to.equal(true)
+  })
+})
+
+describe('getRandomDateInRange', () => {
+  it('should return a random date within the specified range', () => {
+    const startDate = new Date(2024, 0, 1) // January 1, 2024
+    const endDate = new Date(2024, 0, 10) // January 10, 2024
+    const randomDate = getRandomDateInRange(startDate, endDate)
+    expect(randomDate).to.be.instanceOf(Date)
+    expect(randomDate.getTime()).to.be.at.least(startDate.getTime())
+    expect(randomDate.getTime()).to.be.at.most(endDate.getTime())
+  })
+
+  it('should throw an error if the start date and the end date are the same', () => {
+    const startDate = new Date(2024, 0, 1)
+    const endDate = new Date(2024, 0, 1)
+    expect(() => getRandomDateInRange(startDate, endDate)).to.throw(
+      'Start date and end date cannot be the same.'
+    )
+  })
+
+  it('should throw error if the start date is greater than the end date', () => {
+    const startDate = new Date(2024, 0, 10)
+    const endDate = new Date(2024, 0, 1)
+    expect(() => getRandomDateInRange(startDate, endDate)).to.throw(
+      'Start date cannot be greater than end date.'
+    )
+  })
+})