Learn English – The present perfect tense describing a future event

Context, context, context!

Briefly: the simple past is used to narrate past events. The present perfect is used to mention past events which give rise to a present state which is of present interest.

The children played in the sandbox for a while, then moved to the swings. At four o'clock their mother called them inside because it looked like rain.

The children have played in the sandbox and left their toys there. Tell them to go bring their toys inside.

However, the second could also be expressed with a simple past, and would probably be expressed with a past progressive. Play is an activity verb, which doesn't accommodate the perfect all that well. This example, with a telic verb (one which has a distinct change of state in its meaning) may be more instructive.

The children finished their chores, then went outside to play until their mother called them in.

The children have finished their chores; I am going to let them go outside and play now.

As commented by Catija, the first three sentences are perfectly OK and as to the last one, the simple present tense is actually the correct usage.

According to grammar, when you are talking about the future, you should use the present simple in the time (when) clause, not a future form. For example, I'll come when I finish my work. So the correct sentence is:

I want to spend a year travelling when I finish university.

(Reference: The Free Dictionary - the use of "when").