@@ -168,6 +168,7 @@ func (devices *DeviceSetDM) saveMetadata() error {

 }

 func (devices *DeviceSetDM) registerDevice(id int, hash string, size uint64) (*DevInfo, error) {

+	utils.Debugf("registerDevice(%v, %v)", id, hash)

 	info := &DevInfo{

 		Hash:          hash,

 		DeviceId:      id,

@@ -188,7 +189,7 @@ func (devices *DeviceSetDM) registerDevice(id int, hash string, size uint64) (*D

 }

 func (devices *DeviceSetDM) activateDeviceIfNeeded(hash string) error {

-	utils.Debugf("activateDeviceIfNeeded()")

+	utils.Debugf("activateDeviceIfNeeded(%v)", hash)

 	info := devices.Devices[hash]

 	if info == nil {

 		return fmt.Errorf("Unknown device %s", hash)

@@ -560,6 +561,7 @@ func (devices *DeviceSetDM) DeactivateDevice(hash string) error {

 func (devices *DeviceSetDM) Shutdown() error {

 	devices.Lock()

+	utils.Debugf("[devmapper] Shutting down DeviceSet: %s", devices.root)

 	defer devices.Unlock()

 	if !devices.initialized {

@@ -570,6 +570,7 @@ func resumeDevice(name string) error {

 }

 func createDevice(poolName string, deviceId int) error {

+	utils.Debugf("[devmapper] createDevice(poolName=%v, deviceId=%v)", poolName, deviceId)

 	task, err := createTask(DeviceTargetMsg, poolName)

 	if task == nil {

 		return err

@@ -106,6 +106,8 @@ func removeDev(name string) error {

 }

 func cleanupDevMapper() error {

+	utils.Debugf("[devmapper cleanup] starting")

+	defer utils.Debugf("[devmapper cleanup] done")

 	filter := "docker-" + path.Base(unitTestStoreBase)

 	utils.Debugf("Filtering out %s\n", filter)

 	// Unmount any leftover mounts from previous unit test runs

@@ -30,19 +30,25 @@ type Fataler interface {

 	Fatal(args ...interface{})

 }

-func newTestRuntime() (*Runtime, error) {

+func newTestRuntime() (runtime *Runtime, err error) {

+	utils.Debugf("newTestRuntime start")

 	root, err := ioutil.TempDir("", "docker-test")

+	defer func() {

+		utils.Debugf("newTestRuntime: %s", root)

+	}()

 	if err != nil {

 		return nil, err

 	}

 	if err := os.Remove(root); err != nil {

 		return nil, err

 	}

+	utils.Debugf("Copying %s to %s", unitTestStoreBase, root)

 	if err := utils.CopyDirectory(unitTestStoreBase, root); err != nil {

+		utils.Debugf("ERROR: Copying %s to %s returned %s", unitTestStoreBase, root, err)

 		return nil, err

 	}

-	runtime, err := NewRuntimeFromDirectory(root, false)

+	runtime, err = NewRuntimeFromDirectory(root, false)

 	if err != nil {

 		return nil, err

 	}