wrongmove/frontend/src/utils/__tests__/format.test.ts

import { describe, it, expect } from 'vitest';
import {
  EM_DASH,
  formatCurrency,
  formatDate,
  formatDuration,
  formatInteger,
  formatPrice,
  formatPricePerSqm,
  formatPricePerSqmShort,
  isFiniteNumber,
} from '@/utils/format';

describe('formatCurrency', () => {
  it('formats values >= 1000 in compact k notation', () => {
    expect(formatCurrency(1500)).toBe('£1.5k');
    expect(formatCurrency(2500)).toBe('£2.5k');
    expect(formatCurrency(1000000)).toBe('£1000.0k');
  });

  it('formats sub-thousand values as rounded integers', () => {
    expect(formatCurrency(950)).toBe('£950');
    expect(formatCurrency(123.4)).toBe('£123');
  });
});

describe('formatDuration', () => {
  it('renders minutes for sub-hour durations', () => {
    expect(formatDuration(0)).toBe('0m');
    expect(formatDuration(120)).toBe('2m');
    expect(formatDuration(3540)).toBe('59m');
  });

  it('renders hours-and-minutes for multi-hour durations', () => {
    expect(formatDuration(3600)).toBe('1h');
    expect(formatDuration(5400)).toBe('1h30m');
    expect(formatDuration(86400)).toBe('24h');
  });

  // B9 regression cases
  it('returns em-dash for negative seconds (was "-2m")', () => {
    expect(formatDuration(-120)).toBe(EM_DASH);
    expect(formatDuration(-1)).toBe(EM_DASH);
  });

  it('returns em-dash for null and undefined (was "0m")', () => {
    expect(formatDuration(null)).toBe(EM_DASH);
    expect(formatDuration(undefined)).toBe(EM_DASH);
  });

  it('returns em-dash for NaN (was "NaNh")', () => {
    expect(formatDuration(NaN)).toBe(EM_DASH);
  });

  it('returns em-dash for non-finite values (Infinity)', () => {
    expect(formatDuration(Infinity)).toBe(EM_DASH);
    expect(formatDuration(-Infinity)).toBe(EM_DASH);
  });

  it('caps absurdly large values at >24h', () => {
    expect(formatDuration(86401)).toBe('>24h');
    expect(formatDuration(90000)).toBe('>24h');
    expect(formatDuration(31536000)).toBe('>24h'); // 1 year
  });
});

describe('formatDate', () => {
  it('formats valid ISO dates', () => {
    expect(formatDate('2025-01-03T00:00:00Z')).toContain('2025');
  });

  it('returns the input string for invalid dates', () => {
    expect(formatDate('not-a-date')).toBe('not-a-date');
  });
});

describe('formatPricePerSqm', () => {
  it('returns the formatted string when both values are valid', () => {
    expect(formatPricePerSqm(500000, 100)).toBe('£5,000/m²');
  });

  it('returns null when sqm is missing', () => {
    expect(formatPricePerSqm(500000, null)).toBe(null);
    expect(formatPricePerSqm(500000, undefined)).toBe(null);
    expect(formatPricePerSqm(500000, 0)).toBe(null);
  });
});

describe('isFiniteNumber', () => {
  it('returns true for finite numbers', () => {
    expect(isFiniteNumber(0)).toBe(true);
    expect(isFiniteNumber(-1)).toBe(true);
    expect(isFiniteNumber(1.5)).toBe(true);
  });

  it('returns false for non-finite, null, undefined, and other types', () => {
    expect(isFiniteNumber(null)).toBe(false);
    expect(isFiniteNumber(undefined)).toBe(false);
    expect(isFiniteNumber(NaN)).toBe(false);
    expect(isFiniteNumber(Infinity)).toBe(false);
    expect(isFiniteNumber('5')).toBe(false);
  });
});

describe('formatPrice', () => {
  it('formats finite numbers with thousands separators', () => {
    expect(formatPrice(0)).toBe('£0');
    expect(formatPrice(2500)).toBe('£2,500');
    expect(formatPrice(500000)).toBe('£500,000');
    expect(formatPrice(1234.7)).toBe('£1,235');
  });

  // B10 regression: null/undefined must NOT render as "£0"
  it('returns em-dash for null/undefined/non-finite', () => {
    expect(formatPrice(null)).toBe(EM_DASH);
    expect(formatPrice(undefined)).toBe(EM_DASH);
    expect(formatPrice(NaN)).toBe(EM_DASH);
    expect(formatPrice(Infinity)).toBe(EM_DASH);
  });
});

describe('formatPricePerSqmShort', () => {
  it('formats valid positive values', () => {
    expect(formatPricePerSqmShort(38)).toBe('£38/m²');
    expect(formatPricePerSqmShort(4500)).toBe('£4500/m²');
  });

  // B10: zero & negative are missing-data sentinels, not real values
  it('returns em-dash for null/undefined/non-finite/zero/negative', () => {
    expect(formatPricePerSqmShort(null)).toBe(EM_DASH);
    expect(formatPricePerSqmShort(undefined)).toBe(EM_DASH);
    expect(formatPricePerSqmShort(NaN)).toBe(EM_DASH);
    expect(formatPricePerSqmShort(0)).toBe(EM_DASH);
    expect(formatPricePerSqmShort(-5)).toBe(EM_DASH);
  });
});

describe('formatInteger', () => {
  it('rounds and stringifies finite numbers', () => {
    expect(formatInteger(0)).toBe('0');
    expect(formatInteger(3)).toBe('3');
    expect(formatInteger(65.7)).toBe('66');
  });

  it('returns em-dash for null/undefined/non-finite', () => {
    expect(formatInteger(null)).toBe(EM_DASH);
    expect(formatInteger(undefined)).toBe(EM_DASH);
    expect(formatInteger(NaN)).toBe(EM_DASH);
  });
});