Add integration tests for running containers

Add travis support for running integration tests with the client package
and go test framework

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

client_test.go

@@ -1,17 +1,99 @@
 package containerd
 
 import (
+	"bytes"
 	"context"
 	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"syscall"
 	"testing"
+	"time"
 )
 
+const (
+	defaultRoot  = "/var/lib/containerd-test"
+	defaultState = "/run/containerd-test"
+	testImage    = "docker.io/library/alpine:latest"
+)
+
+var address string
+
 func init() {
 	flag.StringVar(&address, "address", "/run/containerd/containerd.sock", "The address to the containerd socket for use in the tests")
 	flag.Parse()
 }
 
-var address string
+func TestMain(m *testing.M) {
+	if testing.Short() {
+		os.Exit(m.Run())
+	}
+	// setup a new containerd daemon if !testing.Short
+	cmd := exec.Command("containerd",
+		"--root", defaultRoot,
+		"--state", defaultState,
+	)
+	buf := bytes.NewBuffer(nil)
+	cmd.Stderr = buf
+	if err := cmd.Start(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	client, err := New(address)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	if err := waitForDaemonStart(client); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	// pull a seed image
+	if _, err = client.Pull(context.Background(), testImage, WithPullUnpack); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+
+	}
+	if err := client.Close(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+	}
+
+	// run the test
+	status := m.Run()
+
+	// tear down the daemon and resources created
+	if err := cmd.Process.Signal(syscall.SIGTERM); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+	}
+	if _, err := cmd.Process.Wait(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+	}
+	if err := os.RemoveAll(defaultRoot); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	// only print containerd logs if the test failed
+	if status != 0 {
+		fmt.Fprintln(os.Stderr, buf.String())
+	}
+	os.Exit(status)
+}
+
+func waitForDaemonStart(client *Client) error {
+	var (
+		serving bool
+		err     error
+	)
+	for i := 0; i < 20; i++ {
+		serving, err = client.IsServing(context.Background())
+		if serving {
+			return nil
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	return fmt.Errorf("containerd did not start within 2s: %v", err)
+}
 
 func TestNewClient(t *testing.T) {
 	if testing.Short() {
@@ -39,8 +121,7 @@ func TestImagePull(t *testing.T) {
 	}
 	defer client.Close()
 
-	const ref = "docker.io/library/alpine:latest"
-	_, err = client.Pull(context.Background(), ref)
+	_, err = client.Pull(context.Background(), testImage)
 	if err != nil {
 		t.Error(err)
 		return