The residents of Heilongjiang province must take four exams per year, and one of them must be taken in Harbin.
I estimate it will be around September next time.
Of course, if there are exams in Changchun, you could also consider taking them in Changchun.
Follow the WeChat official accounts for Heilongjiang Radio Management and Harbin Radio Monitoring, as well as ZhiPu, to get exam information.