JUnit with Kotlin - This class does not have a constructor

I'm trying to implement testing with JUnit4 in my Kotlin application (as kotlin.test seems to be nonexistent in my Kotlin Runtime Library, and I don't now how to get it).
However, I am encountering an error simply by using the Test annotation.
That's my code:

import junit.framework.*

class IntTest {
    @Test    <------------- This line
    fun test1() {

    }
}

On the specified line, Eclipse gives an error message: "This class does not have a constructor".
I don't understand what is the problem. Which class doesn't have a constructor, and why should it have one?