feat: refactor and test tools steps utilities (#42693)

tools/challenge-helper-scripts/helpers/pad-with-leading-zeros.test.js

@@ -0,0 +1,35 @@
+const { padWithLeadingZeros } = require('./pad-with-leading-zeros');
+
+describe('padWithLeadingZeros helper', () => {
+  it('should return a string of 3 digits for valid values', () => {
+    const items = ['1', '11', '111'];
+
+    items.forEach(item => expect(padWithLeadingZeros(item).length).toEqual(3));
+  });
+
+  it('should prepend 0s on valid values while length is less than 3', () => {
+    expect(padWithLeadingZeros('1')).toEqual('001');
+    expect(padWithLeadingZeros('11')).toEqual('011');
+    expect(padWithLeadingZeros('111')).toEqual('111');
+  });
+
+  it('should throw on invalid values', () => {
+    const items = ['undefined', null, []];
+
+    items.forEach(item =>
+      expect(() => {
+        if (item !== 'undefined') {
+          padWithLeadingZeros(item);
+        } else {
+          padWithLeadingZeros();
+        }
+      }).toThrow()
+    );
+  });
+
+  it('should throw on valid values that are longer that 3 characters', () => {
+    expect(() => {
+      padWithLeadingZeros('19850809');
+    }).toThrow();
+  });
+});