rect padding implemet

test/svg-utils.test.js

@@ -29,17 +29,21 @@ describe('svg-utils', () => {
   describe('estimateTextWidth', () => {
     it('should estimate width based on text length and font size', () => {
       const width = estimateTextWidth('Hello', 14);
-      expect(width).toBe(5 * 14 * 0.6); // 42
+      // formula: text.length * fontSize * 0.65 + fontSize * 0.8
+      expect(width).toBe(5 * 14 * 0.65 + 14 * 0.8); // 56.7
     });
 
-    it('should return 0 for empty string', () => {
-      expect(estimateTextWidth('', 14)).toBe(0);
+    it('should include padding for empty string', () => {
+      // Even empty strings get the base padding
+      expect(estimateTextWidth('', 14)).toBe(14 * 0.8); // 11.2
     });
 
-    it('should scale linearly with font size', () => {
+    it('should scale with font size', () => {
       const w1 = estimateTextWidth('test', 10);
       const w2 = estimateTextWidth('test', 20);
-      expect(w2).toBe(w1 * 2);
+      // w1 = 4*10*0.65 + 10*0.8 = 34
+      // w2 = 4*20*0.65 + 20*0.8 = 68
+      expect(w2).toBe(68);
     });
   });
 });