What is test(0) in this snippet from kotlinlang.org?

I'm trying to solve the problem of "runs" in the KotlinKoans page here

Here is my implementation

package runs

fun runs(a: IntArray): Int {
    var numberOfRuns = 1;

    for (index in 0..a.size-2) {
        if (a[index+1] != a[index]) numberOfRuns++
    }

    return numberOfRuns
}

Here is the test suite that runs against the implementation

class Tests {

    @Test fun testRuns1() {
        test(0)
    }

    @Test fun testRuns2() {
        test(1, 1)
    }

    @Test fun testRuns3() {
        test(3, 1, 2, 3)
    }

    @Test fun testRuns4() {
        test(3, 1, 2, 2, 3)
    }

    @Test fun testRuns5() {
        test(3, 1, 1, 2, 3)
    }

    @Test fun testRuns6() {
        test(1, 1, 1, 1, 1)
    }

    @Test fun testRuns7() {
        test(3, 1, 1, 1, 0, 1, 1)
    }

    @Test fun testRuns8() {
        test(3, 1, 1, 1, 0, 1)
    }

    @Test fun testRuns9() {
        test(5, 1, 0, 1, 0, 1)
    }
}

fun test(expected: Int, vararg data: Int) {
    assertEquals(expected, runs(data), "\ndata = ${Arrays.toString(data)}")
}

All test passes except testRuns1(), I don't understand what test(0) does, given that the test() function takes two parametrs as input, an expected value and the actual value. What am I missing?