test(layout): verify all towers have non-negative height values

Author: kanishka-2007-tech

lib/svg/layout.test.ts

@@ -215,6 +215,27 @@ describe('computeTowers edge cases', () => {
     // Assert intensityLevel is calculated correctly based on lines of code (60/60 = 100%, so intensity 4)
     expect(testTower.intensityLevel).toBe(4);
   });
+  it('ensures all tower heights are non-negative', () => {
+    const calendar = {
+      totalContributions: 26,
+      weeks: [
+        {
+          contributionDays: [
+            { contributionCount: 0, date: '2024-06-10' },
+            { contributionCount: 1, date: '2024-06-11' },
+            { contributionCount: 5, date: '2024-06-12' },
+            { contributionCount: 20, date: '2024-06-13' },
+          ],
+        },
+      ],
+    } as unknown as ContributionCalendar;
+
+    const towers = computeTowers(calendar, 'linear', '2024-06-13');
+
+    towers.forEach((tower) => {
+      expect(tower.h).toBeGreaterThanOrEqual(0);
+    });
+  });
 });
 
 it('assigns correct row and col values based on week/day position', () => {