add test around focus/blur

tests/Calendar.spec.jsx

@@ -514,6 +514,32 @@ describe('Calendar', () => {
       expect(onSelect.mock.calls[0][0].format('DD/MM/YYYY')).toBe(expected);
       expect(onChange.mock.calls[0][0].format('DD/MM/YYYY')).toBe(expected);
     });
+
+    it('only reformat the date when the input loses focus', () => {
+      const value = '21/01/17';
+
+      const onSelect = jest.fn();
+      const onChange = jest.fn();
+
+      const calendar = mount(<Calendar
+        format={['DD/MM/YYYY', 'DD/MM/YY']}
+        showToday
+        onSelect={onSelect}
+        onChange={onChange}
+      />);
+
+      const input = calendar.find('.rc-calendar-input').hostNodes().at(0);
+      input.simulate('focus');
+      input.simulate('change', { target: { value } });
+
+      let inputValue = calendar.find('.rc-calendar-input').props().value;
+      expect(inputValue).toBe('21/01/17');
+
+      input.simulate('blur');
+
+      inputValue = calendar.find('.rc-calendar-input').props().value;
+      expect(inputValue).toBe('21/01/2017');
+    });
   });
 
   it('handle clear', () => {