@@ -18,7 +18,7 @@ func TestStart(t *testing.T) {

 		"start_test",

 		"ls",

 		[]string{"-al"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{

 			Ram: 33554432,

 		},

@@ -54,7 +54,7 @@ func TestRun(t *testing.T) {

 		"run_test",

 		"ls",

 		[]string{"-al"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{

 			Ram: 33554432,

 		},

@@ -84,7 +84,7 @@ func TestOutput(t *testing.T) {

 		"output_test",

 		"echo",

 		[]string{"-n", "foobar"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -109,7 +109,7 @@ func TestKill(t *testing.T) {

 		"stop_test",

 		"cat",

 		[]string{"/dev/zero"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -152,7 +152,7 @@ func TestExitCode(t *testing.T) {

 		"exit_test_1",

 		"/bin/true",

 		[]string{""},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -167,7 +167,7 @@ func TestExitCode(t *testing.T) {

 		"exit_test_2",

 		"/bin/false",

 		[]string{""},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -196,7 +196,7 @@ func TestRestart(t *testing.T) {

 		"restart_test",

 		"echo",

 		[]string{"-n", "foobar"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -230,7 +230,7 @@ func TestRestartStdin(t *testing.T) {

 		"restart_stdin_test",

 		"cat",

 		[]string{},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{

 			OpenStdin: true,

 		},

@@ -281,7 +281,7 @@ func TestUser(t *testing.T) {

 		"user_default",

 		"id",

 		[]string{},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -301,7 +301,7 @@ func TestUser(t *testing.T) {

 		"user_root",

 		"id",

 		[]string{},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{

 			User: "root",

 		},

@@ -323,7 +323,7 @@ func TestUser(t *testing.T) {

 		"user_uid0",

 		"id",

 		[]string{},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{

 			User: "0",

 		},

@@ -345,7 +345,7 @@ func TestUser(t *testing.T) {

 		"user_uid1",

 		"id",

 		[]string{},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{

 			User: "1",

 		},

@@ -367,7 +367,7 @@ func TestUser(t *testing.T) {

 		"user_daemon",

 		"id",

 		[]string{},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{

 			User: "daemon",

 		},

@@ -395,7 +395,7 @@ func TestMultipleContainers(t *testing.T) {

 		"container1",

 		"cat",

 		[]string{"/dev/zero"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -407,7 +407,7 @@ func TestMultipleContainers(t *testing.T) {

 		"container2",

 		"cat",

 		[]string{"/dev/zero"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -450,7 +450,7 @@ func TestStdin(t *testing.T) {

 		"stdin_test",

 		"cat",

 		[]string{},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{

 			OpenStdin: true,

 		},

@@ -485,7 +485,7 @@ func TestTty(t *testing.T) {

 		"tty_test",

 		"cat",

 		[]string{},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{

 			OpenStdin: true,

 		},

@@ -521,7 +521,7 @@ func BenchmarkRunSequencial(b *testing.B) {

 			fmt.Sprintf("bench_%v", i),

 			"echo",

 			[]string{"-n", "foo"},

-			[]string{"/var/lib/docker/images/ubuntu"},

+			[]string{testLayerPath},

 			&Config{},

 		)

 		if err != nil {

@@ -557,7 +557,7 @@ func BenchmarkRunParallel(b *testing.B) {

 				fmt.Sprintf("bench_%v", i),

 				"echo",

 				[]string{"-n", "foo"},

-				[]string{"/var/lib/docker/images/ubuntu"},

+				[]string{testLayerPath},

 				&Config{},

 			)

 			if err != nil {

@@ -1,16 +1,42 @@

 package docker

 import (

+	"fmt"

 	"io/ioutil"

+	"log"

 	"os"

+	"os/exec"

 	"testing"

 )

-// Hack to run sys init during unit testing

+const testLayerPath string = "/var/lib/docker/images/docker-ut"

+

 func init() {

+	// Hack to run sys init during unit testing

 	if SelfPath() == "/sbin/init" {

 		SysInit()

 	}

+

+	// Make sure the unit test image is there, download otherwise

+	_, err := os.Stat(testLayerPath)

+	// The image is already there

+	if err == nil {

+		return

+	}

+	// Otherwise, we'll have to fetch it

+	if !os.IsNotExist(err) {

+		panic(err)

+	}

+	log.Printf("Test image not found. Downloading and extracting for the first time.")

+	if err := os.MkdirAll(testLayerPath, 0755); err != nil {

+		panic(err)

+	}

+	cmd := exec.Command("sh", "-c", fmt.Sprintf("wget https://s3.amazonaws.com/docker.io/images/base -O - | tar -jx -C %v/", testLayerPath))

+	cmd.Stdout = os.Stdout

+	cmd.Stderr = os.Stdout

+	if err := cmd.Run(); err != nil {

+		panic(err)

+	}

 }

 func newTestDocker() (*Docker, error) {

@@ -39,7 +65,7 @@ func TestCreate(t *testing.T) {

 		"test_create",

 		"ls",

 		[]string{"-al"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -87,7 +113,7 @@ func TestDestroy(t *testing.T) {

 		"test_destroy",

 		"ls",

 		[]string{"-al"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -135,7 +161,7 @@ func TestGet(t *testing.T) {

 		"test1",

 		"ls",

 		[]string{"-al"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -147,7 +173,7 @@ func TestGet(t *testing.T) {

 		"test2",

 		"ls",

 		[]string{"-al"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -159,7 +185,7 @@ func TestGet(t *testing.T) {

 		"test3",

 		"ls",

 		[]string{"-al"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -196,7 +222,7 @@ func TestRestore(t *testing.T) {

 		"restore_test",

 		"ls",

 		[]string{"-al"},

-		[]string{"/var/lib/docker/images/ubuntu"},

+		[]string{testLayerPath},

 		&Config{},

 	)

 	if err != nil {

@@ -22,7 +22,7 @@ func newTestFilesystem(t *testing.T, layers []string) (rootfs string, fs *Filesy

 }

 func TestFilesystem(t *testing.T) {

-	_, filesystem := newTestFilesystem(t, []string{"/var/lib/docker/images/ubuntu"})

+	_, filesystem := newTestFilesystem(t, []string{testLayerPath})

 	if err := filesystem.Umount(); err == nil {

 		t.Errorf("Umount succeeded even though the filesystem was not mounted")

 	}

@@ -76,7 +76,7 @@ func TestFilesystemMultiLayer(t *testing.T) {

 	}

 	// Create the layered filesystem and add our fake layer on top

-	rootfs, filesystem := newTestFilesystem(t, []string{"/var/lib/docker/images/ubuntu", fakeLayer})

+	rootfs, filesystem := newTestFilesystem(t, []string{testLayerPath, fakeLayer})

 	// Mount it

 	if err := filesystem.Mount(); err != nil {

@@ -102,7 +102,7 @@ func TestFilesystemMultiLayer(t *testing.T) {

 }

 func TestChanges(t *testing.T) {

-	rootfs, filesystem := newTestFilesystem(t, []string{"/var/lib/docker/images/ubuntu"})

+	rootfs, filesystem := newTestFilesystem(t, []string{testLayerPath})

 	// Mount it

 	if err := filesystem.Mount(); err != nil {

 		t.Fatal(err)