feat(contributions): rewrite client config as preset-based helpers

tests/client/contributions.test.js

@@ -0,0 +1,77 @@
+import { describe, it, expect } from 'vitest'
+import {
+  CONTRIBUTION_PRESETS,
+  requiresPayment,
+  isValidContributionAmount,
+  getGuidanceLabel,
+} from '../../app/config/contributions.js'
+
+describe('CONTRIBUTION_PRESETS', () => {
+  it('exposes the five suggested amounts with guidance labels', () => {
+    expect(CONTRIBUTION_PRESETS).toEqual([
+      { amount: 0,  label: 'I need support right now' },
+      { amount: 5,  label: 'I can contribute' },
+      { amount: 15, label: 'I can sustain the community' },
+      { amount: 30, label: 'I can support others too' },
+      { amount: 50, label: 'I want to sponsor multiple members' },
+    ])
+  })
+})
+
+describe('requiresPayment', () => {
+  it('returns false for 0', () => {
+    expect(requiresPayment(0)).toBe(false)
+  })
+  it('returns true for any positive number', () => {
+    expect(requiresPayment(1)).toBe(true)
+    expect(requiresPayment(15)).toBe(true)
+  })
+  it('coerces string numbers', () => {
+    expect(requiresPayment('15')).toBe(true)
+    expect(requiresPayment('0')).toBe(false)
+  })
+})
+
+describe('isValidContributionAmount', () => {
+  it('accepts non-negative integers', () => {
+    expect(isValidContributionAmount(0)).toBe(true)
+    expect(isValidContributionAmount(15)).toBe(true)
+    expect(isValidContributionAmount(9999)).toBe(true)
+  })
+  it('rejects negatives', () => {
+    expect(isValidContributionAmount(-1)).toBe(false)
+  })
+  it('rejects non-integers and non-numbers', () => {
+    expect(isValidContributionAmount(1.5)).toBe(false)
+    expect(isValidContributionAmount('15')).toBe(false)
+    expect(isValidContributionAmount(NaN)).toBe(false)
+    expect(isValidContributionAmount(null)).toBe(false)
+    expect(isValidContributionAmount(undefined)).toBe(false)
+  })
+})
+
+describe('getGuidanceLabel', () => {
+  it('returns the exact preset label when amount matches a preset', () => {
+    expect(getGuidanceLabel(0)).toBe('I need support right now')
+    expect(getGuidanceLabel(5)).toBe('I can contribute')
+    expect(getGuidanceLabel(15)).toBe('I can sustain the community')
+    expect(getGuidanceLabel(30)).toBe('I can support others too')
+    expect(getGuidanceLabel(50)).toBe('I want to sponsor multiple members')
+  })
+  it('returns the nearest-lower preset label for between-preset values', () => {
+    expect(getGuidanceLabel(7)).toBe('I can contribute')
+    expect(getGuidanceLabel(14)).toBe('I can contribute')
+    expect(getGuidanceLabel(40)).toBe('I can support others too')
+    expect(getGuidanceLabel(100)).toBe('I want to sponsor multiple members')
+  })
+  it('coerces string input', () => {
+    expect(getGuidanceLabel('15')).toBe('I can sustain the community')
+  })
+  it('returns null for invalid input', () => {
+    expect(getGuidanceLabel(-1)).toBeNull()
+    expect(getGuidanceLabel(NaN)).toBeNull()
+    expect(getGuidanceLabel('abc')).toBeNull()
+    expect(getGuidanceLabel(null)).toBeNull()
+    expect(getGuidanceLabel(undefined)).toBeNull()
+  })
+})