}
		if tt.n < 0 {
			b := sliceOfString(Split([]byte(tt.s), []byte(tt.sep)))
			if !slices.Equal(result, b) {
				t.Errorf("Split disagrees with SplitN(%q, %q, %d) = %v; want %v", tt.s, tt.sep, tt.n, b, a)
			}
		}
		if len(a) > 0 {
			in, out := a[0], s
			if cap(in) == cap(out) && &in[:1][0] == &out[:1][0] {
				t.Errorf("Join(%#v, %q) didn't copy", a, tt.sep)
			}
		}
	}