for i := 0; i < 1000; i++ {
		h := new(Hash)
		h.SetSeed(s)
		m[h.Sum64()] = struct{}{}
	}
	if len(m) != 1 {
		t.Errorf("seeded hash is random: got %d, want 1", len(m))
	}
}

func TestHashGrouping(t *testing.T) {
	b := bytes.Repeat([]byte("foo"), 100)
	hh := make([]*Hash, 7)
	for i := range hh {
		hh[i] = new(Hash)
	}
	for _, h := range hh[1:] {
		h.SetSeed(hh[0].Seed())
	}
	hh[0].Write(b)