According to a statement from Chinese Government on the Adjustment of Labor Day Holiday Arrangements in 2019, the Labor Day holiday in 2019 has been extended to 4 days, from May 1 to 4.
But April 28 and May 5, 2 Sundays, will be workdays.
Notice of Vacation
How to Reduce Income-tax Burden
Holiday Arrangements for 2019 Made Public by the State Council of Chinese Government