You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mount_test.go
    path of file: ./repos/lotus/markets/dagstore
    
    the code of the file until where you have to start completion: // stm: @unit
package dagstore

import (
	"context"
	"io"
	"net/url"
	"strings"
	"testing"

	"github.com/golang/mock/gomock"
	blocksutil "github.com/ipfs/go-ipfs-blocksutil"
	"github.com/stretchr/testify/require"

	"github.com/filecoin-project/dagstore/mount
    
func TestLotusMountRegistration(t *testing.T) {
	//stm: @MARKET_DAGSTORE_FETCH_UNSEALED_PIECE_001, @MARKET_DAGSTORE_GET_UNPADDED_CAR_SIZE_001
	//stm: @MARKET_DAGSTORE_IS_PIECE_UNSEALED_001
	ctx := context.Background()
	bgen := blocksutil.NewBlockGenerator()
	cid := bgen.Next().Cid()

	// success
	us := lotusScheme + "://" + cid.String()
	u, err := url.Parse(us)
	require.NoError(t, err)

	mockCtrl := gomock.NewController(t)
	// when test is done, assert expectations on all mock objects.
	defer mockCtrl.Finish()

	mockLotusMountAPI := mock_dagstore.NewMockMinerAPI(mockCtrl)
	registry := mount.NewRegistry()
	err = registry.Register(lotusScheme, mountTemplate(mockLotusMountAPI))
	require.NoError(t, err)

	mnt, err := registry.Instantiate(u)
	require.NoError(t, err)

	mockLotusMountAPI.EXPECT().IsUnsealed(ctx, cid).Return(true, nil)
	mockLotusMountAPI.EXPECT().GetUnpaddedCARSize(ctx, cid).Return(uint64(100), nil).Times(1)
	stat, err := mnt.Stat(context.Background())
	require.NoError(t, err)
	require.EqualValues(t, 100, stat.Size)
	require.True(t, stat.Ready)
}