unit root test statistic

You know how the t statistic follows an absolute value rule that if the absolute value of the t statistic is greater than the critical t stat, we reject. does the absolute value also occur for the unit root test statistic and the heteroskedascity test statistic?

Yes it does, but you have to take into account that some hypothesis testings have differens Ho and Ha so once rejection, the other time failure to reject says that model is correctly specified.