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Validating Russian Locale Implementation in dayjs

This test suite validates Russian (ru) locale functionality in the dayjs library, focusing on date formatting, relative time calculations, and meridiem handling. The tests ensure proper Russian language support and compatibility with moment.js implementations.

Test Coverage Overview

The test suite provides comprehensive coverage of Russian locale-specific date formatting and time calculations.

Month formatting in Russian language
Relative time expressions in Russian
Russian-specific meridiem (time of day) handling
Comparison with moment.js output for validation

Implementation Analysis

The testing approach utilizes Jest’s assertion framework to validate Russian locale implementations against moment.js reference outputs.

Key patterns include:

Iterative testing of date formats over multiple days
Parameterized relative time testing
Direct string comparison for meridiem values
Mock date manipulation for consistent testing

Technical Details

Testing infrastructure includes:

Jest testing framework
MockDate for date manipulation
dayjs with relativeTime plugin
moment.js for reference comparisons
Russian locale imports for both libraries

Best Practices Demonstrated

The test suite exemplifies robust testing practices for internationalization features.

Consistent test setup and teardown using beforeEach/afterEach
Comprehensive format testing with multiple patterns
Edge case coverage in relative time calculations
Systematic time-of-day testing for meridiem

iamkun/dayjs

test/locale/ru.test.js

            
import moment from 'moment'
import MockDate from 'mockdate'
import dayjs from '../../src'
import relativeTime from '../../src/plugin/relativeTime'
import '../../src/locale/ru'

dayjs.extend(relativeTime)

beforeEach(() => {
  MockDate.set(new Date())
})

afterEach(() => {
  MockDate.reset()
})

it('Format Month with locale function', () => {
  for (let i = 0; i <= 7; i += 1) {
    const dayjsRU = dayjs().locale('ru').add(i, 'day')
    const momentRU = moment().locale('ru').add(i, 'day')
    const testFormat1 = 'DD MMMM YYYY MMM'
    const testFormat2 = 'MMMM'
    const testFormat3 = 'MMM'
    expect(dayjsRU.format(testFormat1)).toEqual(momentRU.format(testFormat1))
    expect(dayjsRU.format(testFormat2)).toEqual(momentRU.format(testFormat2))
    expect(dayjsRU.format(testFormat3)).toEqual(momentRU.format(testFormat3))
  }
})

it('RelativeTime: Time from X', () => {
  const T = [
    [44.4, 'second'], // a few seconds
    [89.5, 'second'], // a minute
    [43, 'minute'], // 44 minutes
    [21, 'hour'], // 21 hours
    [25, 'day'], // 25 days
    [10, 'month'], // 2 month
    [18, 'month'] // 2 years
  ]

  T.forEach((t) => {
    dayjs.locale('ru')
    moment.locale('ru')
    expect(dayjs().from(dayjs().add(t[0], t[1])))
      .toBe(moment().from(moment().add(t[0], t[1])))
    expect(dayjs().from(dayjs().add(t[0], t[1]), true))
      .toBe(moment().from(moment().add(t[0], t[1]), true))
  })
})

it('Meridiem', () => {
  expect(dayjs('2020-01-01 03:00:00').locale('ru').format('A')).toEqual('ночи')
  expect(dayjs('2020-01-01 11:00:00').locale('ru').format('A')).toEqual('утра')
  expect(dayjs('2020-01-01 16:00:00').locale('ru').format('A')).toEqual('дня')
  expect(dayjs('2020-01-01 20:00:00').locale('ru').format('A')).toEqual('вечера')
})