adding tests

Author: jycouet

test/unit/app/utils/chart-data-prediction.spec.ts

@@ -0,0 +1,180 @@
+import { describe, expect, it, vi } from 'vitest'
+
+vi.mock('~/utils/chart-data-correction', () => ({
+  applyDataCorrection: (data: { value: number }[]) => data,
+}))
+
+import {
+  endDateOnlyToUtcMs,
+  getBucketStartUtc,
+  getBucketEndUtc,
+  getCompletionRatio,
+  linearProject,
+  extrapolateLastValue,
+} from '../../../../app/utils/chart-data-prediction'
+
+describe('endDateOnlyToUtcMs', () => {
+  it('parses a valid date', () => {
+    expect(endDateOnlyToUtcMs('2025-03-15')).toBe(Date.UTC(2025, 2, 15, 23, 59, 59, 999))
+  })
+
+  it('returns null for invalid formats', () => {
+    expect(endDateOnlyToUtcMs('not-a-date')).toBeNull()
+    expect(endDateOnlyToUtcMs('2025/03/15')).toBeNull()
+    expect(endDateOnlyToUtcMs('')).toBeNull()
+  })
+})
+
+describe('getBucketStartUtc', () => {
+  // Friday 2025-11-07 at 06:05:04
+  const ts = Date.UTC(2025, 10, 7, 6, 5, 4)
+
+  it('yearly → Jan 1st', () => {
+    expect(getBucketStartUtc(ts, 'yearly')).toBe(Date.UTC(2025, 0, 1))
+  })
+
+  it('monthly → 1st of month', () => {
+    expect(getBucketStartUtc(ts, 'monthly')).toBe(Date.UTC(2025, 10, 1))
+  })
+
+  it('weekly → previous Monday', () => {
+    expect(getBucketStartUtc(ts, 'weekly')).toBe(Date.UTC(2025, 10, 3))
+  })
+
+  it('weekly on a Monday returns that Monday', () => {
+    const monday = Date.UTC(2025, 10, 3, 6, 5, 4)
+    expect(getBucketStartUtc(monday, 'weekly')).toBe(Date.UTC(2025, 10, 3))
+  })
+
+  it('weekly on a Sunday returns previous Monday', () => {
+    const sunday = Date.UTC(2025, 10, 9, 6, 5, 4)
+    expect(getBucketStartUtc(sunday, 'weekly')).toBe(Date.UTC(2025, 10, 3))
+  })
+
+  it('daily → start of day', () => {
+    expect(getBucketStartUtc(ts, 'daily')).toBe(Date.UTC(2025, 10, 7))
+  })
+})
+
+describe('getBucketEndUtc', () => {
+  // Friday 2025-11-07 at 06:05:04
+  const ts = Date.UTC(2025, 10, 7, 6, 5, 4)
+
+  it('yearly → Jan 1st next year', () => {
+    expect(getBucketEndUtc(ts, 'yearly')).toBe(Date.UTC(2026, 0, 1))
+  })
+
+  it('monthly → 1st of next month', () => {
+    expect(getBucketEndUtc(ts, 'monthly')).toBe(Date.UTC(2025, 11, 1))
+  })
+
+  it('weekly → Monday + 7 days', () => {
+    expect(getBucketEndUtc(ts, 'weekly')).toBe(Date.UTC(2025, 10, 10))
+  })
+
+  it('daily → next day', () => {
+    expect(getBucketEndUtc(ts, 'daily')).toBe(Date.UTC(2025, 10, 8))
+  })
+})
+
+describe('getCompletionRatio', () => {
+  it('returns 0 at bucket start', () => {
+    const start = Date.UTC(2025, 2, 1)
+    expect(getCompletionRatio(start, 'monthly', start)).toBe(0)
+  })
+
+  it('returns 1 at bucket end', () => {
+    const start = Date.UTC(2025, 2, 1)
+    const end = Date.UTC(2025, 3, 1)
+    expect(getCompletionRatio(start, 'monthly', end)).toBe(1)
+  })
+
+  it('returns ~0.5 at midpoint', () => {
+    const start = Date.UTC(2025, 0, 1)
+    const mid = Date.UTC(2025, 0, 1, 12, 0)
+    expect(getCompletionRatio(start, 'daily', mid)).toBeCloseTo(0.5)
+  })
+
+  it('clamps to [0, 1]', () => {
+    const start = Date.UTC(2025, 2, 1)
+    expect(getCompletionRatio(start, 'monthly', start - 1000)).toBe(0)
+    expect(getCompletionRatio(start, 'monthly', Date.UTC(2025, 5, 1))).toBe(1)
+  })
+})
+
+describe('linearProject', () => {
+  it('returns null with fewer than 2 points', () => {
+    expect(linearProject([])).toBeNull()
+    expect(linearProject([5])).toBeNull()
+  })
+
+  it('projects a linear trend', () => {
+    expect(linearProject([10, 20, 30])).toBeCloseTo(40)
+  })
+
+  it('floors negative projections to 0', () => {
+    expect(linearProject([100, 10, 1])).toBe(0)
+  })
+
+  it('handles constant series', () => {
+    expect(linearProject([5, 5, 5])).toBeCloseTo(5)
+  })
+})
+
+describe('extrapolateLastValue', () => {
+  it('returns raw last value when ratio >= 1 (complete bucket)', () => {
+    const lastDateMs = Date.UTC(2025, 1, 1)
+    const result = extrapolateLastValue({
+      series: [100, 200, 150],
+      granularity: 'monthly',
+      lastDateMs,
+      referenceMs: Date.UTC(2025, 2, 1), // bucket fully elapsed
+      predictionPoints: 4,
+    })
+    expect(result).toBe(150)
+  })
+
+  it('returns raw last value when predictionPoints <= 0', () => {
+    const result = extrapolateLastValue({
+      series: [100, 200, 50],
+      granularity: 'monthly',
+      lastDateMs: Date.UTC(2025, 2, 1),
+      referenceMs: Date.UTC(2025, 2, 15),
+      predictionPoints: 0,
+    })
+    expect(result).toBe(50)
+  })
+
+  it('uses linear projection when enough lookback points', () => {
+    const result = extrapolateLastValue({
+      series: [100, 200, 300, 50],
+      granularity: 'monthly',
+      lastDateMs: Date.UTC(2025, 2, 1),
+      referenceMs: Date.UTC(2025, 2, 15),
+      predictionPoints: 4,
+    })
+    expect(result).toBeCloseTo(400)
+  })
+
+  it('copies single lookback point when only one available', () => {
+    const result = extrapolateLastValue({
+      series: [100, 10],
+      granularity: 'monthly',
+      lastDateMs: Date.UTC(2025, 2, 1),
+      referenceMs: Date.UTC(2025, 2, 15),
+      predictionPoints: 4,
+    })
+    expect(result).toBe(100)
+  })
+
+  it('falls back to proportional scale-up with no lookback', () => {
+    const result = extrapolateLastValue({
+      series: [50],
+      granularity: 'daily',
+      lastDateMs: Date.UTC(2025, 2, 12),
+      referenceMs: Date.UTC(2025, 2, 12, 12, 0), // half day
+      predictionPoints: 4,
+    })
+    expect(result).toBeCloseTo(100)
+  })
+})