Add show error when attach to a paused container

Signed-off-by: Lei Jitang <leijitang@huawei.com>
Upstream-commit: de1d611990a80cf4a38ec501469c08c1aeee2d60
Component: engine

components/engine/integration-cli/docker_cli_attach_test.go

@@ -9,6 +9,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/docker/docker/pkg/integration/checker"
 	"github.com/go-check/check"
 )
 
@@ -150,3 +151,12 @@ func (s *DockerSuite) TestAttachDisconnect(c *check.C) {
 	c.Assert(err, check.IsNil)
 	c.Assert(running, check.Equals, "true")
 }
+
+func (s *DockerSuite) TestAttachPausedContainer(c *check.C) {
+	defer unpauseAllContainers()
+	dockerCmd(c, "run", "-d", "--name=test", "busybox", "top")
+	dockerCmd(c, "pause", "test")
+	out, _, err := dockerCmdWithError("attach", "test")
+	c.Assert(err, checker.NotNil, check.Commentf(out))
+	c.Assert(out, checker.Contains, "You cannot attach to a paused container, unpause it first")
+}