test(utils): add verification for username truncation over 30 chars (JhaSourav07#1724)

## Description

Fixes JhaSourav07#1553 

## Pillar

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

## Visual Preview

## 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=YOUR_USERNAME`).
- [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.
- [x] The SVG output matches the CommitPulse "premium quality" aesthetic
standard (no raw elements, smooth animations, correct fonts).
- [x] (Recommended) I joined the CommitPulse Discord community for
contributor discussions, mentorship, and faster PR support.

Author: JhaSourav07

lib/svg/generator.test.ts

@@ -1355,4 +1355,53 @@ describe('Radar Scan Line Animation Alignment', () => {
     expect(svg).toContain('width="600"');
     expect(svg).toContain('height="420"');
   });
+
+  it('safely truncates usernames longer than 30 chars with trailing dots without changing CSS geometry', () => {
+    // 1. Arrange: Create usernames (one short baseline, one strictly > 30 chars)
+    const shortUsername = 'avi';
+    const longUsername = 'ThisIsAVeryLongUsernameThatExceedsThirtyCharacters';
+    const expectedTruncated = longUsername.slice(0, 12) + '...';
+
+    const paramsBaseline = {
+      user: shortUsername,
+      size: 'medium',
+      autoTheme: false,
+    } as unknown as BadgeParams;
+    const paramsLong = {
+      user: longUsername,
+      size: 'medium',
+      autoTheme: false,
+    } as unknown as BadgeParams;
+
+    // 2. Act: Truncate username and generate SVGs
+    const truncatedName = truncateUsername(longUsername);
+    const svgBaseline = generateSVG(mockStats, paramsBaseline, mockCalendar);
+    const svgLong = generateSVG(mockStats, paramsLong, mockCalendar);
+
+    // Helper to extract critical SVG geometry attributes
+    const extractGeometry = (svgStr: string) => {
+      const width = svgStr.match(/width="([^"]*)"/)?.[1];
+      const height = svgStr.match(/height="([^"]*)"/)?.[1];
+      const viewBox = svgStr.match(/viewBox="([^"]*)"/)?.[1];
+      return { width, height, viewBox };
+    };
+
+    // 3. Assertions:
+
+    // A. Verify exact expected truncation value on the helper utility
+    expect(truncatedName).toBe(expectedTruncated);
+
+    // B. Verify the visible <text class="title"> tag contains exactly the truncated name and NOT the full username
+    const textTitleMatch = svgLong.match(/<text[^>]*class="title"[^>]*>([^<]*)<\/text>/);
+    expect(textTitleMatch).not.toBeNull();
+    const renderedTitleText = textTitleMatch?.[1];
+
+    expect(renderedTitleText).toBe(expectedTruncated.toUpperCase());
+    expect(renderedTitleText).not.toContain(longUsername.toUpperCase());
+
+    // C. Verify geometry remains completely unchanged compared to the baseline
+    const geometryBaseline = extractGeometry(svgBaseline);
+    const geometryLong = extractGeometry(svgLong);
+    expect(geometryLong).toEqual(geometryBaseline);
+  });
 });