runtime: Allock mockfs storage to be placed in any directory

Currently EnableMockTesting() takes no arguments and will always place the
mock storage in the fixed location /tmp/vc/mockfs.  This means that one
test run can interfere with the next one if anything isn't cleaned up
(and there are other bugs which means that happens).  If if those were
fixed this would allow developers testing on the same machine to interfere
with each other.

So, allow the mockfs to be placed at an arbitrary place given as a
parameter to EnableMockTesting().  In TestMain() we place it under our
existing temporary directory, so we don't need any additional cleanup just
for the mockfs.

fixes #4140

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
(cherry picked from commit 1b931f4203)
Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

src/runtime/virtcontainers/persist/fs/mockfs.go

@@ -7,25 +7,27 @@ package fs
 
 import (
 	"fmt"
-	"os"
 	"path/filepath"
 
 	persistapi "github.com/kata-containers/kata-containers/src/runtime/virtcontainers/persist/api"
 )
 
-var mockTesting = false
+var mockRootPath = ""
 
 type MockFS struct {
 	// inherit from FS. Overwrite if needed.
 	*FS
 }
 
-func EnableMockTesting() {
-	mockTesting = true
+func EnableMockTesting(rootPath string) {
+	mockRootPath = rootPath
 }
 
 func MockStorageRootPath() string {
-	return filepath.Join(os.TempDir(), "vc", "mockfs")
+	if mockRootPath == "" {
+		panic("Using uninitialized mock storage root path")
+	}
+	return mockRootPath
 }
 
 func MockRunStoragePath() string {
@@ -54,7 +56,7 @@ func MockFSInit(rootPath string) (persistapi.PersistDriver, error) {
 }
 
 func MockAutoInit() (persistapi.PersistDriver, error) {
-	if mockTesting {
+	if mockRootPath != "" {
 		return MockFSInit(MockStorageRootPath())
 	}
 	return nil, nil

src/runtime/virtcontainers/persist/fs/mockfs_test.go

@@ -13,19 +13,19 @@ import (
 
 func TestMockAutoInit(t *testing.T) {
 	assert := assert.New(t)
-	orgMockTesting := mockTesting
+	orgMockRootPath := mockRootPath
 	defer func() {
-		mockTesting = orgMockTesting
+		mockRootPath = orgMockRootPath
 	}()
 
-	mockTesting = false
+	mockRootPath = ""
 
 	fsd, err := MockAutoInit()
 	assert.Nil(fsd)
 	assert.NoError(err)
 
 	// Testing mock driver
-	mockTesting = true
+	mockRootPath = t.TempDir()
 	fsd, err = MockAutoInit()
 	assert.NoError(err)
 	expectedFS, err := MockFSInit(MockStorageRootPath())

src/runtime/virtcontainers/virtcontainers_test.go

@@ -57,8 +57,6 @@ var testHyperstartTtySocket = ""
 // cleanUp Removes any stale sandbox/container state that can affect
 // the next test to run.
 func cleanUp() {
-	os.RemoveAll(fs.MockRunStoragePath())
-	os.RemoveAll(fs.MockRunVMStoragePath())
 	syscall.Unmount(GetSharePath(testSandboxID), syscall.MNT_DETACH|UmountNoFollow)
 	os.RemoveAll(testDir)
 	os.MkdirAll(testDir, DirMode)
@@ -107,8 +105,6 @@ func setupClh() {
 func TestMain(m *testing.M) {
 	var err error
 
-	fs.EnableMockTesting()
-
 	flag.Parse()
 
 	logger := logrus.NewEntry(logrus.New())
@@ -125,6 +121,8 @@ func TestMain(m *testing.M) {
 		panic(err)
 	}
 
+	fs.EnableMockTesting(filepath.Join(testDir, "mockfs"))
+
 	fmt.Printf("INFO: Creating virtcontainers test directory %s\n", testDir)
 	err = os.MkdirAll(testDir, DirMode)
 	if err != nil {