FEAT-7: statistics aggregation module - litters/year, avg litter size, Farbschlag distribution, population curve, losses (9 tests)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

gerbil-manager-web/src/statistics/__tests__/aggregate.test.ts

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+/** FEAT-7: Tests der Statistik-Aggregationen (reine Daten, kein DOM). */
+import { describe, expect, it } from 'vitest'
+import type { Gerbil, GerbilStatus, Litter } from '../../api/types'
+import {
+  avgLitterSizePerYear,
+  farbschlagDistribution,
+  littersPerYear,
+  lossesPerYear,
+  populationOverTime,
+} from '../aggregate'
+
+function makeLitter(date: string, totalBorn: number | null = null): Litter {
+  return {
+    id: `l-${date}-${Math.abs(totalBorn ?? 0)}-${counter++}`,
+    name: 'Wurf',
+    date,
+    totalBorn,
+    expectedGoHomeDate: null,
+    notes: null,
+    fatherId: null,
+    motherId: null,
+  }
+}
+let counter = 0
+
+function makeGerbil(over: Partial<Gerbil> & { id: string }): Gerbil {
+  return {
+    name: over.id,
+    gender: 'unknown',
+    status: 'Active' as GerbilStatus,
+    dateOfBirth: null,
+    dateOfDeath: null,
+    causeOfDeath: null,
+    goHomeDate: null,
+    litterId: null,
+    enclosureId: null,
+    colorVarietyId: null,
+    originContactId: null,
+    receiverContactId: null,
+    genotype: null,
+    notes: null,
+    ...over,
+  }
+}
+
+describe('littersPerYear', () => {
+  it('zählt pro Jahr und füllt Lücken mit 0', () => {
+    const result = littersPerYear([
+      makeLitter('2021-03-01'),
+      makeLitter('2021-09-10'),
+      makeLitter('2023-01-05'),
+    ])
+    expect(result).toEqual([
+      { year: 2021, value: 2 },
+      { year: 2022, value: 0 },
+      { year: 2023, value: 1 },
+    ])
+  })
+
+  it('leere Eingabe → leere Reihe', () => {
+    expect(littersPerYear([])).toEqual([])
+  })
+})
+
+describe('avgLitterSizePerYear', () => {
+  it('mittelt nur Würfe mit erfasster Wurfstärke und lässt Jahre ohne Daten aus', () => {
+    const result = avgLitterSizePerYear([
+      makeLitter('2021-01-01', 4),
+      makeLitter('2021-06-01', 6),
+      makeLitter('2022-01-01', null), // zählt nicht
+      makeLitter('2023-01-01', 5),
+    ])
+    expect(result).toEqual([
+      { year: 2021, value: 5 },
+      { year: 2023, value: 5 }, // 2022 fehlt bewusst (kein 0-Durchschnitt)
+    ])
+  })
+})
+
+describe('farbschlagDistribution', () => {
+  it('zählt nur aktive Tiere, sortiert absteigend, null-Eimer zuletzt', () => {
+    const gerbils = [
+      makeGerbil({ id: 'a', colorVarietyId: 'Schwarz' }),
+      makeGerbil({ id: 'b', colorVarietyId: 'Schwarz' }),
+      makeGerbil({ id: 'c', colorVarietyId: 'Agouti' }),
+      makeGerbil({ id: 'd', colorVarietyId: null }),
+      makeGerbil({ id: 'e', colorVarietyId: 'Gold', status: 'Deceased' }), // inaktiv
+    ]
+    const result = farbschlagDistribution(gerbils, (g) => g.colorVarietyId)
+    expect(result).toEqual([
+      { name: 'Schwarz', count: 2 },
+      { name: 'Agouti', count: 1 },
+      { name: null, count: 1 },
+    ])
+  })
+
+  it('sortiert bei Gleichstand alphabetisch (de)', () => {
+    const gerbils = [
+      makeGerbil({ id: 'a', colorVarietyId: 'Zobel' }),
+      makeGerbil({ id: 'b', colorVarietyId: 'Ägypter' }),
+    ]
+    const names = farbschlagDistribution(gerbils, (g) => g.colorVarietyId).map((e) => e.name)
+    expect(names).toEqual(['Ägypter', 'Zobel'])
+  })
+})
+
+describe('populationOverTime', () => {
+  it('bildet Geburt/Tod/Abgabe als Bestandskurve mit Monatsabtastung ab', () => {
+    const gerbils = [
+      makeGerbil({ id: 'a', dateOfBirth: '2024-01-15' }),
+      makeGerbil({ id: 'b', dateOfBirth: '2024-02-20' }),
+      makeGerbil({
+        id: 'c',
+        dateOfBirth: '2024-01-20',
+        status: 'Deceased',
+        dateOfDeath: '2024-03-10',
+      }),
+      makeGerbil({
+        id: 'd',
+        dateOfBirth: '2024-02-01',
+        status: 'GivenAway',
+        goHomeDate: '2024-04-05',
+      }),
+    ]
+    const points = populationOverTime(gerbils, '2024-04-15')
+    expect(points).toEqual([
+      { date: '2024-01-01', value: 0 }, // vor allen Ereignissen
+      { date: '2024-02-01', value: 3 }, // a, c geboren + d (Geburt genau am Stichtag zählt mit)
+      { date: '2024-03-01', value: 4 },
+      { date: '2024-04-01', value: 3 }, // c verstorben am 10.03.
+      { date: '2024-04-15', value: 2 }, // d abgegeben am 05.04.
+    ])
+  })
+
+  it('Tiere ohne Geburtsdatum werden übersprungen; leer → []', () => {
+    expect(populationOverTime([makeGerbil({ id: 'x' })], '2024-01-01')).toEqual([])
+    expect(populationOverTime([], '2024-01-01')).toEqual([])
+  })
+
+  it('Endpunkt heute wird nicht doppelt erzeugt, wenn heute ein Monatsanfang ist', () => {
+    const gerbils = [makeGerbil({ id: 'a', dateOfBirth: '2024-01-15' })]
+    const points = populationOverTime(gerbils, '2024-03-01')
+    expect(points[points.length - 1]).toEqual({ date: '2024-03-01', value: 1 })
+    expect(points.filter((p) => p.date === '2024-03-01')).toHaveLength(1)
+  })
+})
+
+describe('lossesPerYear', () => {
+  it('zählt Todesfälle pro Jahr (nur Status Verstorben, mit Todesdatum)', () => {
+    const gerbils = [
+      makeGerbil({ id: 'a', status: 'Deceased', dateOfDeath: '2021-05-01' }),
+      makeGerbil({ id: 'b', status: 'Deceased', dateOfDeath: '2023-02-02' }),
+      makeGerbil({ id: 'c', status: 'Deceased', dateOfDeath: null }), // ohne Datum: nicht zuordenbar
+      makeGerbil({ id: 'd', status: 'GivenAway', goHomeDate: '2022-01-01' }), // kein Todesfall
+    ]
+    expect(lossesPerYear(gerbils)).toEqual([
+      { year: 2021, value: 1 },
+      { year: 2022, value: 0 },
+      { year: 2023, value: 1 },
+    ])
+  })
+})