[metrics-core] calculateUserCC가 임의 lookback 기간의 NRR을 항상 30일로 환산해 수용 한계를 왜곡한다 #3218

import { defineConfig } from 'vitest/config';
import { resolve } from 'node:path';

export default defineConfig({
  resolve: {
    alias: {
      '@croco/problems-core': resolve('packages/problems-core/src/index.ts'),
      '@croco/framework-context': resolve('packages/framework-context/src/index.ts'),
      '@croco/telemetry-api': resolve('packages/telemetry-api/src/index.ts'),
    },
  },
  test: { include: ['audit-data/D*.spec.ts'], maxWorkers: 1, testTimeout: 10000 },
});

import { it, expect } from 'vitest';
import { CarryingCapacityCalculator } from '../packages/metrics-core/src/index';
import type { MetricsRepository } from '../packages/metrics-core/src/index';

const providers = (inflow: number, retention: MetricsRepository['getRetentionMetrics']) => ({
 users: { getDailyActiveUsers: async () => 100, getNewUsersCount: async () => inflow, getChurnedUsersCount: async () => 0 },
 repo: { recordMRRMovement: async () => {}, recordSnapshot: async () => {}, getSnapshot: async () => null, getMRRHistory: async () => [], getRetentionMetrics: retention } satisfies MetricsRepository
});
it('D05 derives daily churn from the actual lookback period', async () => {
  const calls: number[] = [];
  const {users, repo} = providers(100, async (_tenant, period) => {
   const days = (period.to.getTime() - period.from.getTime()) / 86400000;
   calls.push(days);
   return { logoChurn: 0, revenueChurn: 0, grr: 100 * Math.exp(-0.01 * days), nrr: 100 * Math.exp(-0.01 * days) };
  });
  const calculator = new CarryingCapacityCalculator(users, repo);
  const days30 = await calculator.calculateUserCC({ tenantId: 'sample-tenant', lookbackDays: 30 });
  const days60 = await calculator.calculateUserCC({ tenantId: 'sample-tenant', lookbackDays: 60 });
  console.log('D05', JSON.stringify({ calls, capacity30: days30?.capacity, capacity60: days60?.capacity, churn30: days30?.dailyChurnRate, churn60: days60?.dailyChurnRate }));
  expect(days30?.capacity).toBeCloseTo(10000);
  expect(days60?.capacity).toBeCloseTo(10000);
 });