Testing lists in GO

I'm trying to implement a test in GO. But I'm struggling with the list's syntax inside the struct.

package primeFactor

import "testing"

var testCases = []struct {
    p        int
    expected []int
}{
    {15, [3,5]},
    {26, [2,13]},
    {37, [37]},
    {42, [2,3,7]},
}

func TestPrimeFactor(t *testing.T) {
    for _, test := range testCases {
        observed := PrimeFactor(test.p)
        if observed != test.expected {
            t.Error("For p = %d, expected %t. Got %t.",
                test.p, test.expected, observed)
        }
    }
}

The output error I have is:

expected ']', found ','
: expected operand, found '{'
: expected ';', found 'for'

I appreciate your help. Thanks.