cloned from https://github.com/diskfs/go-diskfs

purpose: test if it supports ext3/ext4.

[fat32]

with an image that has fat32 file system, things work fine: Take a look at the test func TestRead, which reads an image with fat32 file system

➜ go-diskfs git:(master) go test diskfs_test.go
ok command-line-arguments 0.066s

[ext4]

However, if we switch the image to a ubuntu image, http://cloud-images.ubuntu.com/minimal/releases/disco/release-20190417/ubuntu-19.04-minimal-cloudimg-amd64.img, the test failed. This means it does not apply to ubuntu image. It does not help if we try to read file system from a different partition (via disk.GetPartitionTable()).