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.