test(theme-glacier): verify color variables and configuration for glacier theme (JhaSourav07#3273)

## Description
Fixes JhaSourav07#2321

## Pillar
- [ ] 🎨 Pillar 1 — New Theme Design
- [ ] 📐 Pillar 2 — Geometric SVG Improvement
- [ ] 🕐 Pillar 3 — Timezone Logic Optimization
- [x] 🛠️ Other (Bug fix, refactoring, docs)

## Visual Preview
No SVG changes — test-only PR. All 5 tests pass locally.

## Checklist before requesting a review:
- [x] I have read the `CONTRIBUTING.md` file.
- [x] I have tested these changes locally
(`localhost:3000/api/streak?user=Tapasya-12`).
- [x] I have run `npm run format` and `npm run lint` locally and
resolved all errors (CI will fail otherwise).
- [x] My commits follow the Conventional Commits format (e.g.,
`feat(themes): ...`, `fix(calculate): ...`).
- [ ] I have updated `README.md` if I added a new theme or URL
parameter.
- [x] I have started the repo.
- [x] I have made sure that i have only one commit to merge in this PR.
- [ ] The SVG output matches the CommitPulse "premium quality" aesthetic
standard (no raw elements, smooth animations, correct fonts).
- [ ] (Recommended) I joined the CommitPulse Discord community for
contributor discussions, mentorship, and faster PR support.

Author: JhaSourav07

lib/svg/glacier.test.ts

@@ -0,0 +1,124 @@
+import { describe, it, expect } from 'vitest';
+import { themes } from './themes';
+import { generateSVG } from './generator';
+import type { StreakStats, ContributionCalendar, BadgeParams } from '../../types/index';
+
+const mockStats: StreakStats = {
+  currentStreak: 5,
+  longestStreak: 10,
+  totalContributions: 120,
+  todayDate: '2024-06-01',
+};
+
+const mockCalendar: ContributionCalendar = {
+  totalContributions: 120,
+  weeks: [
+    {
+      contributionDays: [
+        { contributionCount: 3, date: '2024-05-26' },
+        { contributionCount: 0, date: '2024-05-27' },
+        { contributionCount: 5, date: '2024-05-28' },
+        { contributionCount: 2, date: '2024-05-29' },
+        { contributionCount: 4, date: '2024-05-30' },
+        { contributionCount: 1, date: '2024-05-31' },
+        { contributionCount: 6, date: '2024-06-01' },
+      ],
+    },
+  ],
+};
+
+const glacierAccent = Array.isArray(themes.glacier.accent)
+  ? themes.glacier.accent[0]
+  : themes.glacier.accent;
+
+const mockParams = {
+  user: 'octocat',
+  bg: themes.glacier.bg,
+  text: themes.glacier.text,
+  accent: glacierAccent,
+  size: 'medium',
+  scale: 'linear',
+  grace: 1,
+  refresh: false,
+  hide_title: false,
+  hide_background: false,
+  hide_stats: false,
+  lang: 'en',
+  view: 'default',
+  delta_format: 'percent',
+  mode: 'commits',
+  entrance: 'rise',
+  format: 'svg',
+  radius: 8,
+  speed: '8s',
+  opacity: 1.0,
+  labels: false,
+  shading: false,
+  gradient: false,
+  disable_particles: false,
+  glow: true,
+} as BadgeParams;
+
+const HEX_REGEX = /^[0-9a-fA-F]{3}$|^[0-9a-fA-F]{6}$/;
+
+function hexToRgb(hex: string): [number, number, number] {
+  const h = hex.replace('#', '');
+  const full =
+    h.length === 3
+      ? h
+          .split('')
+          .map((c) => c + c)
+          .join('')
+      : h;
+  const n = parseInt(full, 16);
+  return [(n >> 16) & 255, (n >> 8) & 255, n & 255];
+}
+
+function relativeLuminance(hex: string): number {
+  const [r, g, b] = hexToRgb(hex).map((c) => {
+    const s = c / 255;
+    return s <= 0.03928 ? s / 12.92 : Math.pow((s + 0.055) / 1.055, 2.4);
+  });
+  return 0.2126 * r + 0.7152 * g + 0.0722 * b;
+}
+
+function contrastRatio(hex1: string, hex2: string): number {
+  const l1 = relativeLuminance(hex1);
+  const l2 = relativeLuminance(hex2);
+  const lighter = Math.max(l1, l2);
+  const darker = Math.min(l1, l2);
+  return (lighter + 0.05) / (darker + 0.05);
+}
+
+describe('glacier theme', () => {
+  it('exists as a key in the themes object', () => {
+    expect(Object.hasOwn(themes, 'glacier')).toBe(true);
+  });
+
+  it('has valid hex color strings for bg, text, and accent', () => {
+    const { bg, text, accent } = themes.glacier;
+    const accentStr = Array.isArray(accent) ? accent[0] : accent;
+    expect(HEX_REGEX.test(bg)).toBe(true);
+    expect(HEX_REGEX.test(text)).toBe(true);
+    expect(HEX_REGEX.test(accentStr)).toBe(true);
+  });
+
+  it('has the correct specific color values', () => {
+    expect(themes.glacier.bg).toBe('e0f2fe');
+    expect(themes.glacier.text).toBe('0369a1');
+    expect(glacierAccent).toBe('06b6d4');
+  });
+
+  it('meets WCAG AA contrast ratio (≥ 4.5) between bg and text', () => {
+    const ratio = contrastRatio(themes.glacier.bg, themes.glacier.text);
+    expect(ratio).toBeGreaterThanOrEqual(4.5);
+  });
+
+  it('generates SVG output containing the glacier theme hex colors', () => {
+    const svg = generateSVG(mockStats, mockParams, mockCalendar);
+    expect(typeof svg).toBe('string');
+    expect(svg.length).toBeGreaterThan(100);
+    expect(svg).toMatch(new RegExp(`#?${glacierAccent}`, 'i'));
+    expect(svg).toContain('<svg');
+  });
+});