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mountinfo: simplify test prep
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1. Drop the last argument of tMount as it's always "".

2. Drop the error return of tMount, instead use t.Fatal.

3. Do the same for prepare. Fix the doc accordingly.

4. Add tCreateFile helper.

5. Change MkdirTemp to Mkdir since we have a new empty directory.

6. Inline some t.TempDir() calls.

7. Sprinkle t.Helper().

Signed-off-by: Kir Kolyshkin <[email protected]>
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@kolyshkin
kolyshkin committed Sep 24, 2024
1 parent 29394de commit 0046da9
Showing 1 changed file with 111 additions and 119 deletions.
230 changes: 111 additions & 119 deletions mountinfo/mounted_linux_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -15,252 +15,247 @@ import (

// tMount is a wrapper for unix.Mount which is used to prepare test cases.
// It skips the test case if mounting is not possible (i.e. user is not root),
// adds more context to mount error, if any, and installs a cleanup handler to
// undo the mount.
func tMount(t *testing.T, src, dst, fstype string, flags uintptr, options string) error {
// fails the test case if there is a mount error, and installs a cleanup
// handler to undo the mount.
func tMount(t *testing.T, src, dst, fstype string, flags uintptr) {
if os.Getuid() != 0 {
t.Skip("root required for mounting")
}

err := unix.Mount(src, dst, fstype, flags, options)
err := unix.Mount(src, dst, fstype, flags, "")
if err != nil {
return &os.PathError{Path: dst, Op: "mount", Err: err}
t.Helper()
t.Fatal(&os.PathError{Path: dst, Op: "mount", Err: err})
}
t.Cleanup(func() {
if err := unix.Unmount(dst, unix.MNT_DETACH); err != nil {
t.Helper()
t.Errorf("cleanup: unmount %q failed: %v", dst, err)
}
})
return nil
}

func tCreateFile(t *testing.T, dir string) string {
file, err := os.CreateTemp(dir, "file")
if err != nil {
t.Fatal(err)
}
file.Close()
return file.Name()
}

type testMount struct {
desc string
isNotExist bool
isMount bool
isBind bool
// prepare returns a path that needs to be checked, and the error, if any.
// prepare returns a path that needs to be checked.
// If there is an error preparing the path, the test is either skipped or failed.
//
// It is responsible for cleanup (by using t.Cleanup).
//
// It should not fail the test (i.e. no calls to t.Error/t.Fatal).
// The only exception to this rule is some cases use t.TempDir() for
// simplicity (no need to check for errors or call t.Cleanup()), and
// it may call t.Fatal, but practically we don't expect it.
prepare func(t *testing.T) (string, error)
prepare func(t *testing.T) string
}

var testMounts = []testMount{
{
desc: "non-existent path",
isNotExist: true,
prepare: func(t *testing.T) (string, error) {
return "/non/existent/path", nil
prepare: func(t *testing.T) string {
return "/non/existent/path"
},
},
{
desc: "not mounted directory",
prepare: func(t *testing.T) (dir string, err error) {
dir = t.TempDir()
return dir, err
prepare: func(t *testing.T) string {
return t.TempDir()
},
},
{
desc: "tmpfs mount",
isMount: true,
prepare: func(t *testing.T) (mnt string, err error) {
mnt = t.TempDir()
err = tMount(t, "tmpfs", mnt, "tmpfs", 0, "")
return mnt, err
prepare: func(t *testing.T) string {
mnt := t.TempDir()
tMount(t, "tmpfs", mnt, "tmpfs", 0)
return mnt
},
},
{
desc: "tmpfs mount ending with a slash",
isMount: true,
prepare: func(t *testing.T) (mnt string, err error) {
mnt = t.TempDir() + "/"
err = tMount(t, "tmpfs", mnt, "tmpfs", 0, "")
return mnt, err
prepare: func(t *testing.T) string {
mnt := t.TempDir() + "/"
tMount(t, "tmpfs", mnt, "tmpfs", 0)
return mnt
},
},
{
desc: "broken symlink",
isNotExist: true,
prepare: func(t *testing.T) (link string, err error) {
dir := t.TempDir()
link = filepath.Join(dir, "broken-symlink")
err = os.Symlink("/some/non/existent/dest", link)
return link, err
prepare: func(t *testing.T) string {
link := filepath.Join(t.TempDir(), "broken-symlink")
err := os.Symlink("/some/non/existent/dest", link)
if err != nil {
t.Fatal(err)
}
return link
},
},
{
desc: "symlink to not mounted directory",
prepare: func(t *testing.T) (link string, err error) {
prepare: func(t *testing.T) string {
tmp := t.TempDir()

dir, err := os.MkdirTemp(tmp, "dir")
t.Helper()
dir := filepath.Join(tmp, "dir")
err := os.Mkdir(dir, 0o700)
if err != nil {
return
t.Fatal(err)
}

link = filepath.Join(tmp, "symlink")
link := filepath.Join(tmp, "symlink")
err = os.Symlink(dir, link)
if err != nil {
t.Fatal(err)
}

return link, err
return link
},
},
{
desc: "symlink to mounted directory",
isMount: true,
prepare: func(t *testing.T) (link string, err error) {
prepare: func(t *testing.T) string {
tmp := t.TempDir()

dir, err := os.MkdirTemp(tmp, "dir")
t.Helper()
dir := filepath.Join(tmp, "dir")
err := os.Mkdir(dir, 0o700)
if err != nil {
return
t.Fatal(err)
}

err = tMount(t, "tmpfs", dir, "tmpfs", 0, "")
if err != nil {
return
}
tMount(t, "tmpfs", dir, "tmpfs", 0)

link = filepath.Join(tmp, "symlink")
link := filepath.Join(tmp, "symlink")
err = os.Symlink(dir, link)
if err != nil {
t.Fatal(err)
}

return link, err
return link
},
},
{
desc: "symlink to a file on a different filesystem",
isMount: false,
prepare: func(t *testing.T) (link string, err error) {
prepare: func(t *testing.T) string {
tmp := t.TempDir()

mnt, err := os.MkdirTemp(tmp, "dir")
t.Helper()
mnt := filepath.Join(tmp, "dir")
err := os.Mkdir(mnt, 0o700)
if err != nil {
return
t.Fatal(err)
}

err = tMount(t, "tmpfs", mnt, "tmpfs", 0, "")
if err != nil {
return
}
file, err := os.CreateTemp(mnt, "file")
tMount(t, "tmpfs", mnt, "tmpfs", 0)
file := tCreateFile(t, mnt)
link := filepath.Join(tmp, "link")
err = os.Symlink(file, link)
if err != nil {
return
t.Fatal(err)
}
file.Close()
link = filepath.Join(tmp, "link")
err = os.Symlink(file.Name(), link)

return link, err
return link
},
},
{
desc: "path whose parent is a symlink to directory on another device",
isMount: false,
prepare: func(t *testing.T) (path string, err error) {
prepare: func(t *testing.T) string {
tmp := t.TempDir()

mnt, err := os.MkdirTemp(tmp, "dir")
t.Helper()
mnt := filepath.Join(tmp, "dir")
err := os.Mkdir(mnt, 0o700)
if err != nil {
return
t.Fatal(err)
}

err = tMount(t, "tmpfs", mnt, "tmpfs", 0, "")
if err != nil {
return
}
file, err := os.CreateTemp(mnt, "file")
if err != nil {
return
}
file.Close()

tMount(t, "tmpfs", mnt, "tmpfs", 0)
file := tCreateFile(t, mnt)
// Create link -> mnt under tmp dir.
link := filepath.Join(tmp, "link")
err = os.Symlink(filepath.Base(mnt), link)
if err != nil {
t.Fatal(err)
}
// Path to check is /<tmp>/link/file.
path = filepath.Join(link, filepath.Base(file.Name()))

return path, err
return filepath.Join(link, filepath.Base(file))
},
},
{
desc: "directory bind mounted to itself",
isMount: true,
isBind: true,
prepare: func(t *testing.T) (mnt string, err error) {
mnt = t.TempDir()
err = tMount(t, mnt, mnt, "", unix.MS_BIND, "")
return mnt, err
prepare: func(t *testing.T) string {
mnt := t.TempDir()
tMount(t, mnt, mnt, "", unix.MS_BIND)
return mnt
},
},
{
desc: "directory bind-mounted to other directory",
isMount: true,
isBind: true,
prepare: func(t *testing.T) (mnt string, err error) {
dir := t.TempDir()
mnt = t.TempDir()
err = tMount(t, dir, mnt, "", unix.MS_BIND, "")
return mnt, err
prepare: func(t *testing.T) string {
mnt := t.TempDir()
tMount(t, t.TempDir(), mnt, "", unix.MS_BIND)
return mnt
},
},
{
desc: "not mounted file",
prepare: func(t *testing.T) (path string, err error) {
dir := t.TempDir()
file, err := os.CreateTemp(dir, "file")
if err != nil {
return
}
return file.Name(), err
prepare: func(t *testing.T) string {
return tCreateFile(t, t.TempDir())
},
},
{
desc: "regular file bind-mounted to itself",
isMount: true,
isBind: true,
prepare: func(t *testing.T) (path string, err error) {
dir := t.TempDir()

file, err := os.CreateTemp(dir, "file")
if err != nil {
return
}
file.Close()
path = file.Name()

err = tMount(t, path, path, "", unix.MS_BIND, "")

return path, err
prepare: func(t *testing.T) string {
file := tCreateFile(t, t.TempDir())
tMount(t, file, file, "", unix.MS_BIND)
return file
},
},
{
desc: "not mounted socket",
prepare: func(t *testing.T) (path string, err error) {
dir := t.TempDir()
path = filepath.Join(dir, "sock")
_, err = net.Listen("unix", path)
return path, err
prepare: func(t *testing.T) string {
path := filepath.Join(t.TempDir(), "sock")
_, err := net.Listen("unix", path)
if err != nil {
t.Helper()
t.Fatal(err)
}
return path
},
},
{
desc: "socket bind-mounted to itself",
isMount: true,
isBind: true,
prepare: func(t *testing.T) (path string, err error) {
dir := t.TempDir()
path = filepath.Join(dir, "sock")
_, err = net.Listen("unix", path)
prepare: func(t *testing.T) string {
path := filepath.Join(t.TempDir(), "sock")
_, err := net.Listen("unix", path)
if err != nil {
return
t.Helper()
t.Fatal(err)
}
err = tMount(t, path, path, "", unix.MS_BIND, "")
tMount(t, path, path, "", unix.MS_BIND)

return path, err
return path
},
},
}
Expand Down Expand Up @@ -345,10 +340,7 @@ func TestMountedBy(t *testing.T) {
for _, tc := range testMounts {
tc := tc
t.Run(tc.desc, func(t *testing.T) {
m, err := tc.prepare(t)
if err != nil {
t.Fatalf("prepare: %v", err)
}
m := tc.prepare(t)

// Check the public Mounted() function as a whole.
mounted, err := Mounted(m)
Expand Down

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