We will take the test.
We will have the test.
Could I use both forms?
Both sentences are correct, but not necessarily interchangeable.
We will have the test, to me means that a teacher is telling the class about the test.
We will take the test, to me means that there is a group of students who are talking about a test. Example: "We will take the test, even though we really don't want to."
I am not a teacher.