func (vfs *fs) GetFileFromVirtualFS(path string) (string, error) {
	file, err := vfs.vfs.ReadFile(path)
	if err != nil {
		return "", errors.New(GetFileFromVirtualFSError)
	}
	return string(file), nil
}
GetFileFromVirtualFS return a file from virtual fs
package fs
import (
	"errors"
	"io/ioutil"
	"os"
)
const GetFileFromVirtualFSError = "open file from vfs error"
const GetFileFromFSError = "open file from user fs error"
type fs struct {
	vfs VFS
}
type VFS interface {
	ReadFile(path string) ([]byte, error)
}
type FS interface {
	GetFileFromVirtualFS(path string) (string, error)
	GetFileFromFS(path string) (string, error)
	GetCurrentDirectory() (string, error)
}
func NewFs(vfs VFS) FS {
	return &fs{
		vfs: vfs,
	}
}