This a binomial test and I can give you an

if you give me a decision rule/critical region.
Similarly if you give me an

I can then give you the critical region.
Clearly we reject the null hypothesis and accept the alternative for small X,
since p under the alternative is smaller than p under the null.
If we make the critical region X=0,
then
and

when p=2/5.
If we make the critical region X=0 or X=1, then
and

when p=2/5.