feat: add Crontab Guru tool for parsing and validating crontab expressions

src/pages/tools/time/crontab-guru/crontab-guru.service.test.ts

@@ -0,0 +1,26 @@
+import { expect, describe, it } from 'vitest';
+import { validateCrontab, explainCrontab } from './service';
+
+describe('crontab-guru service', () => {
+  it('validates correct crontab expressions', () => {
+    expect(validateCrontab('35 16 * * 0-5')).toBe(true);
+    expect(validateCrontab('* * * * *')).toBe(true);
+    expect(validateCrontab('0 12 1 * *')).toBe(true);
+  });
+
+  it('invalidates incorrect crontab expressions', () => {
+    expect(validateCrontab('invalid expression')).toBe(false);
+    expect(validateCrontab('61 24 * * *')).toBe(false);
+  });
+
+  it('explains valid crontab expressions', () => {
+    expect(explainCrontab('35 16 * * 0-5')).toMatch(/At 04:35 PM/);
+    expect(explainCrontab('* * * * *')).toMatch(/Every minute/);
+  });
+
+  it('returns error for invalid crontab explanation', () => {
+    expect(explainCrontab('invalid expression')).toMatch(
+      /Invalid crontab expression/
+    );
+  });
+});