func init() {
	registerDBCreator("prefixdb", func(name, dir string) (tmdb.DB, error) {
		mdb := memdb.NewDB()
		mdb.Set([]byte("a"), []byte{1})
		mdb.Set([]byte("b"), []byte{2})
		mdb.Set([]byte("t"), []byte{20})
		mdb.Set([]byte("test"), []byte{0})
		mdb.Set([]byte("u"), []byte{21})
		mdb.Set([]byte("z"), []byte{26})
		return tmdb.NewPrefixDB(mdb, []byte("test/")), nil
	}, false)
}
Register a test backend for PrefixDB as well, with some unrelated junk data
package metadb
import (
	"fmt"
	"io/ioutil"
	"os"
	"testing"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	tmdb "github.com/tendermint/tm-db"
	"github.com/tendermint/tm-db/cleveldb"
	"github.com/tendermint/tm-db/goleveldb"
	"github.com/tendermint/tm-db/internal/dbtest"
	"github.com/tendermint/tm-db/memdb"
	"github.com/tendermint/tm-db/rocksdb"
)