for i := range b {
			idx := Index(b[i:], q[:j])
			if idx != -1 {
				t.Fatalf("Index(b[%d:], q[:%d])=%d, want -1\n", i, j, idx)
			}
		}
		q[j-1] = 0
	}

	// Test differing alignments and sizes of q which always end on a page boundary.
	q[len(q)-1] = 1 // difference is only found on the last byte
	for j := 0; j < len(q); j++ {
		for i := range b {
			idx := Index(b[i:], q[j:])
			if idx != -1 {

			if name == "" {
				continue
			}

			if idx, ok := files[name]; ok {
				r.fileList[idx].isDup = true
				continue
			}
			if idx, ok := knownDirs[name]; ok {
				r.fileList[idx].isDup = true
				continue
			}

			for dir := path.Dir(name); dir != "."; dir = path.Dir(dir) {
				dirs[dir] = true
			}

			idx := len(r.fileList)
			entry := fileListEntry{
				name:  name,

		t.Fatal(err)
	}
	b := buf.Bytes()

	var sig [4]byte
	binary.LittleEndian.PutUint32(sig[:], uint32(fileHeaderSignature))

	idx := bytes.Index(b, sig[:])
	if idx == -1 {
		t.Fatal("file header not found")
	}
	b = b[idx:]

	if !bytes.Equal(b[6:10], []byte{0, 0, 0, 0}) { // FileHeader.Flags: 0, FileHeader.Method: 0
		t.Errorf("unexpected method and flags: %v", b[6:10])
	}