Question re: unpaired two-sample difference in means testing

Consider a canonical example for the unpaired two-sample difference in means test: two groups of students took the same exam (sizes of the groups need not be equal), one received a treatment while the other did not. Determine whether the difference in the mean test scores of the respective groups is statistically significant.

My question is whether the items making up the samples (ie the distribution of test scores) need to be normally distributed or whether it's sufficient for the …

canonical datascience difference exam example mean students test testing treatment