package routing

import (
	"reflect"
	"testing"
)

func TestSliceInto(t *testing.T) {
	slice := []string{"a", "b", "c", "d", "e", "f", "g"}
	limit := int16(3)
	testCases := []struct {
		since      int64
		wantPrev   int
		wantNext   int
		wantSubset []string
	}{
		{
			since:      0,
			wantPrev:   -1,
			wantNext:   3,
			wantSubset: slice[0:3],
		},
		{
			since:      3,
			wantPrev:   0,
			wantNext:   6,
			wantSubset: slice[3:6],
		},
		{
			since:      6,
			wantPrev:   3,
			wantNext:   -1,
			wantSubset: slice[6:7],
		},
	}
	for _, tc := range testCases {
		subset, prev, next := sliceInto(slice, tc.since, limit)
		if !reflect.DeepEqual(subset, tc.wantSubset) {
			t.Errorf("returned subset is wrong, got %v want %v", subset, tc.wantSubset)
		}
		if prev != tc.wantPrev {
			t.Errorf("returned prev is wrong, got %d want %d", prev, tc.wantPrev)
		}
		if next != tc.wantNext {
			t.Errorf("returned next is wrong, got %d want %d", next, tc.wantNext)
		}
	}
}