test: add svg constants error resilience coverage

Author: coffeee27

lib/svg/constants.error-resilience.test.ts

@@ -0,0 +1,44 @@
+import { describe, expect, it } from 'vitest';
+import {
+  CONTRIBUTION_MILESTONES,
+  FONT_MAP,
+  GHOST_HEIGHT_PX,
+  LINEAR_SCALE_MULTIPLIER,
+  LOG_SCALE_MULTIPLIER,
+  MAX_LINEAR_HEIGHT,
+  MAX_LOG_HEIGHT,
+  STREAK_MILESTONES,
+  SVG_HEIGHT,
+  SVG_WIDTH,
+} from './constants';
+
+describe('SVG constants error resilience', () => {
+  it('provides stable dimensions during hydration', () => {
+    expect(SVG_WIDTH).toBeGreaterThan(0);
+    expect(SVG_HEIGHT).toBeGreaterThan(0);
+  });
+
+  it('provides safe fallback scaling values', () => {
+    expect(GHOST_HEIGHT_PX).toBeGreaterThan(0);
+    expect(LOG_SCALE_MULTIPLIER).toBeGreaterThan(0);
+    expect(LINEAR_SCALE_MULTIPLIER).toBeGreaterThan(0);
+    expect(MAX_LOG_HEIGHT).toBeGreaterThan(0);
+    expect(MAX_LINEAR_HEIGHT).toBeGreaterThan(0);
+  });
+
+  it('provides font fallbacks for rendering recovery', () => {
+    expect(FONT_MAP.jetbrains).toContain('monospace');
+    expect(FONT_MAP.fira).toContain('monospace');
+    expect(FONT_MAP.roboto).toContain('sans-serif');
+  });
+
+  it('maintains valid contribution milestone fallback data', () => {
+    expect(CONTRIBUTION_MILESTONES.length).toBeGreaterThan(0);
+    expect(CONTRIBUTION_MILESTONES.every((v) => v > 0)).toBe(true);
+  });
+
+  it('maintains valid streak milestone fallback data', () => {
+    expect(STREAK_MILESTONES.length).toBeGreaterThan(0);
+    expect(STREAK_MILESTONES.every((v) => v > 0)).toBe(true);
+  });
+});