Update core package tests

Author: Pascal Wegner

packages/core/src/hooks/useTimerMachine.ts

@@ -1,3 +1,5 @@
+/* istanbul ignore file */
+/* covered by app integration test */
 import { useMachine } from '@xstate/react';
 
 import { timerMachine } from '../machine/timerMachine';

packages/core/src/utils/__tests__/toTwoDigitString.test.ts

@@ -0,0 +1,8 @@
+import { toTwoDigitString } from '../toTwoDigitString';
+
+describe('toTwoDigitString()', () => {
+  it('should return two digit string', () => {
+    expect(toTwoDigitString(3)).toBe('03');
+    expect(toTwoDigitString(30)).toBe('30');
+  });
+});