fix: address PR review feedback

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: asizikov

README.md

@@ -66,7 +66,7 @@ npm run preview
 3. The app will parse the report and compare request-based and AI Credits-based billing signals
 4. Explore the visualizations and data views to preview how future bills may look after the AI Credits transition
 
-If you don't have your own data yet, you can use any GitHub Copilot billing CSV export that matches the current format, including the `aic_quantity` and `aic_gross_amount` columns.
+If you don't have your own data yet, export a GitHub Copilot billing CSV from your organization that matches the current format, including the `aic_quantity` and `aic_gross_amount` columns.
 
 ## CSV Report Format
 

src/pipeline/aggregators/aicDiscountAggregation.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest'
 import type { TokenUsageRecord } from '../parser'
-import { calculateAicDiscountAmount, calculateSavingsDifference } from '../../views/billingComparison'
+import { calculateAicDiscountAmount, calculateSavingsDifference } from '../../utils/billingComparison'
 import { CostCenterAggregator } from './costCenterAggregator'
 import { DailyUsageAggregator } from './dailyUsageAggregator'
 import { ModelUsageAggregator } from './modelUsageAggregator'
@@ -61,15 +61,12 @@ function sum(values: number[]): number {
 describe('derived AIC discount aggregation', () => {
   it('derives organization AIC discount as gross minus net', () => {
     const result = aggregate([createRecord({ aic_gross_amount: 1.5, aic_net_amount: 0.6 })])
+    const organization = result.organizations.organizations[0]
 
-    expect(result.organizations.organizations).toEqual([
-      expect.objectContaining({
-        organization: 'octo',
-        aicGrossAmount: 1.5,
-        aicNetAmount: 0.6,
-        aicDiscountAmount: 0.9,
-      }),
-    ])
+    expect(organization.organization).toBe('octo')
+    expect(organization.aicGrossAmount).toBeCloseTo(1.5)
+    expect(organization.aicNetAmount).toBeCloseTo(0.6)
+    expect(organization.aicDiscountAmount).toBeCloseTo(0.9)
   })
 
   it('derives cost-center AIC discount from totals gross minus net', () => {

src/pipeline/aggregators/pruAggregation.test.ts

@@ -103,6 +103,10 @@ function sumNumbers(values: number[]): number {
   return values.reduce((total, value) => total + value, 0)
 }
 
+function expectCloseMoney(actual: number, expected: number): void {
+  expect(actual).toBeCloseTo(expected)
+}
+
 function expectNetEquation(totals: { grossAmount: number; discountAmount: number; netAmount: number }): void {
   expect(totals.grossAmount - totals.discountAmount).toBeCloseTo(totals.netAmount)
 }
@@ -180,23 +184,23 @@ describe('PRU gross/net/discount aggregation', () => {
       dailyDiscount: userDiscount,
     })
 
-    expect(result.organizations.organizations).toEqual([
-      expect.objectContaining({
-        organization: 'octo',
-        requests: 23,
-        grossAmount: 7,
-        discountAmount: 1.7,
-        netAmount: 5.3,
-      }),
-    ])
+    const organization = result.organizations.organizations[0]
+    expect(organization.organization).toBe('octo')
+    expect(organization.requests).toBe(23)
+    expectCloseMoney(organization.grossAmount, 7)
+    expectCloseMoney(organization.discountAmount, 1.7)
+    expectCloseMoney(organization.netAmount, 5.3)
   })
 
   it('keeps cost-center totals aligned with per-model and per-user rollups', () => {
     const result = aggregate(createFixture())
     const cats = result.costCenters.costCenters.find((costCenter) => costCenter.costCenterName === 'Cats')
 
     expect(cats).toBeDefined()
-    expect(cats?.totals).toEqual(expect.objectContaining({ requests: 15, grossAmount: 3, discountAmount: 0.7, netAmount: 2.3 }))
+    expect(cats?.totals.requests).toBe(15)
+    expectCloseMoney(cats!.totals.grossAmount, 3)
+    expectCloseMoney(cats!.totals.discountAmount, 0.7)
+    expectCloseMoney(cats!.totals.netAmount, 2.3)
     expect(sumNumbers(Object.values(cats?.totalsByModel ?? {}).map((totals) => totals.grossAmount))).toBeCloseTo(cats!.totals.grossAmount)
     expect(sumNumbers(Object.values(cats?.totalsByModel ?? {}).map((totals) => totals.netAmount))).toBeCloseTo(cats!.totals.netAmount)
     expect(sumNumbers(Object.values(cats?.totalsByUser ?? {}).map((totals) => totals.grossAmount))).toBeCloseTo(cats!.totals.grossAmount)

src/utils/billingComparison.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from 'vitest'
+import { calculateAicDiscountAmount, calculateSavingsDifference } from './billingComparison'
+
+describe('billing comparison helpers', () => {
+  it('derives AIC discount as gross minus net for fully covered usage', () => {
+    expect(calculateAicDiscountAmount(1.2, 0)).toBeCloseTo(1.2)
+  })
+
+  it('derives AIC discount as 0 for uncovered usage', () => {
+    expect(calculateAicDiscountAmount(1.2, 1.2)).toBeCloseTo(0)
+  })
+
+  it('derives AIC discount as only the covered portion for partial usage', () => {
+    expect(calculateAicDiscountAmount(1.2, 0.45)).toBeCloseTo(0.75)
+  })
+
+  it('derives displayed savings as PRU net minus AIC net', () => {
+    expect(calculateSavingsDifference(5.3, 1.1)).toBeCloseTo(4.2)
+  })
+})

src/views/billingComparison.ts src/utils/billingComparison.tssrc/views/billingComparison.ts renamed to src/utils/billingComparison.ts

@@ -1,7 +1,7 @@
 import { useMemo, useState } from 'react'
 import type { CostCenterResult } from '../pipeline/aggregators/costCenterAggregator'
+import { calculateAicDiscountAmount, calculateSavingsDifference } from '../utils/billingComparison'
 import { formatAic, formatDifference, formatUsd } from '../utils/format'
-import { calculateAicDiscountAmount, calculateSavingsDifference } from './billingComparison'
 
 export function CostCentersView({ data, rangeStart }: { data: CostCenterResult; rangeStart?: string | null }) {
   const [selected, setSelected] = useState<string>(data.costCenters[0]?.costCenterName ?? '')

src/views/CostCentersView.tsx

@@ -1,9 +1,9 @@
 import { useState, useMemo } from 'react'
 import type { ModelUsageResult, ModelDailyUsageData } from '../pipeline/aggregators/modelUsageAggregator'
 import { DualAxisLineChart, MultiSeriesStackedBarChart } from '../components'
+import { calculateAicDiscountAmount, calculateSavingsDifference } from '../utils/billingComparison'
 import { fillDataForRange } from '../utils/fillDataForRange'
 import { formatAic, formatUsd } from '../utils/format'
-import { calculateAicDiscountAmount, calculateSavingsDifference } from './billingComparison'
 
 function createEmptyModelDailyUsage(date: string): ModelDailyUsageData {
   return {

src/views/ModelsView.tsx

@@ -1,6 +1,6 @@
 import type { OrganizationResult } from '../pipeline/aggregators/organizationAggregator'
 import { formatAic, formatDifference, formatUsd } from '../utils/format'
-import { calculateSavingsDifference } from './billingComparison'
+import { calculateSavingsDifference } from '../utils/billingComparison'
 
 export function OrganizationsView({ data }: { data: OrganizationResult }) {
   if (data.organizations.length === 0) {

src/views/OrganizationsView.tsx

@@ -1,9 +1,9 @@
 import { useMemo } from 'react'
 import { MultiSeriesStackedBarChart } from '../components'
 import type { UserDailyUsage, UserUsage } from '../pipeline/aggregators/userUsageAggregator'
+import { calculateAicDiscountAmount, calculateSavingsDifference } from '../utils/billingComparison'
 import { fillDataForRange } from '../utils/fillDataForRange'
 import { formatAic } from '../utils/format'
-import { calculateAicDiscountAmount, calculateSavingsDifference } from './billingComparison'
 
 type DailySummaryModelRow = {
   model: string