[ADD] Add/Substract duration test cases
[ADD] Add/Substract duration test cases

samwize/YLMoment,yannickl/YLMoment,yannickl/YLMoment,ReutersTV/YLMoment,strictlyd/YLMoment,samwize/YLMoment,rcgary/YLMoment,strictlyd/YLMoment,zxl20zxl/YLMoment,ReutersTV/YLMoment,rcgary/YLMoment,samwize/YLMoment,zxl20zxl/YLMoment