Remove most of the runCommandWithOutput from integration tests

There is 5 calls left, that use StdinPipe that is not yet supported by
icmd.

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

integration-cli/daemon/daemon.go

@@ -586,14 +586,14 @@ func (d *Daemon) GetBaseDeviceSize(c *check.C) int64 {
 // Cmd executes a docker CLI command against this daemon.
 // Example: d.Cmd("version") will run docker -H unix://path/to/unix.sock version
 func (d *Daemon) Cmd(args ...string) (string, error) {
-	b, err := d.Command(args...).CombinedOutput()
-	return string(b), err
+	result := icmd.RunCmd(d.Command(args...))
+	return result.Combined(), result.Error
 }
 
 // Command creates a docker CLI command against this daemon, to be executed later.
 // Example: d.Command("version") creates a command to run "docker -H unix://path/to/unix.sock version"
-func (d *Daemon) Command(args ...string) *exec.Cmd {
-	return exec.Command(d.dockerBinary, d.PrependHostArg(args)...)
+func (d *Daemon) Command(args ...string) icmd.Cmd {
+	return icmd.Command(d.dockerBinary, d.PrependHostArg(args)...)
 }
 
 // PrependHostArg prepend the specified arguments by the daemon host flags

integration-cli/docker_api_containers_test.go

@@ -31,9 +31,7 @@ import (
 )
 
 func (s *DockerSuite) TestContainerAPIGetAll(c *check.C) {
-	startCount, err := getContainerCount()
-	c.Assert(err, checker.IsNil, check.Commentf("Cannot query container count"))
-
+	startCount := getContainerCount(c)
 	name := "getall"
 	dockerCmd(c, "run", "--name", name, "busybox", "true")
 
@@ -354,8 +352,7 @@ func (s *DockerSuite) TestContainerAPIPause(c *check.C) {
 	c.Assert(err, checker.IsNil)
 	c.Assert(status, checker.Equals, http.StatusNoContent)
 
-	pausedContainers, err := getPausedContainers()
-	c.Assert(err, checker.IsNil, check.Commentf("error thrown while checking if containers were paused"))
+	pausedContainers := getPausedContainers(c)
 
 	if len(pausedContainers) != 1 || stringid.TruncateID(ContainerID) != pausedContainers[0] {
 		c.Fatalf("there should be one paused container and not %d", len(pausedContainers))
@@ -365,8 +362,7 @@ func (s *DockerSuite) TestContainerAPIPause(c *check.C) {
 	c.Assert(err, checker.IsNil)
 	c.Assert(status, checker.Equals, http.StatusNoContent)
 
-	pausedContainers, err = getPausedContainers()
-	c.Assert(err, checker.IsNil, check.Commentf("error thrown while checking if containers were paused"))
+	pausedContainers = getPausedContainers(c)
 	c.Assert(pausedContainers, checker.HasLen, 0, check.Commentf("There should be no paused container."))
 }
 

integration-cli/docker_cli_build_test.go

@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"reflect"
 	"regexp"
@@ -1149,10 +1148,7 @@ func (s *DockerSuite) TestBuildWithInaccessibleFilesInContext(c *check.C) {
 }
 
 func (s *DockerSuite) TestBuildForceRm(c *check.C) {
-	containerCountBefore, err := getContainerCount()
-	if err != nil {
-		c.Fatalf("failed to get the container count: %s", err)
-	}
+	containerCountBefore := getContainerCount(c)
 	name := "testbuildforcerm"
 
 	buildImage(name, withBuildFlags("--force-rm"), withBuildContext(c,
@@ -1162,11 +1158,7 @@ func (s *DockerSuite) TestBuildForceRm(c *check.C) {
 		ExitCode: 1,
 	})
 
-	containerCountAfter, err := getContainerCount()
-	if err != nil {
-		c.Fatalf("failed to get the container count: %s", err)
-	}
-
+	containerCountAfter := getContainerCount(c)
 	if containerCountBefore != containerCountAfter {
 		c.Fatalf("--force-rm shouldn't have left containers behind")
 	}
@@ -1196,19 +1188,12 @@ func (s *DockerSuite) TestBuildRm(c *check.C) {
 	}
 
 	for _, tc := range testCases {
-		containerCountBefore, err := getContainerCount()
-		if err != nil {
-			c.Fatalf("failed to get the container count: %s", err)
-		}
+		containerCountBefore := getContainerCount(c)
 
 		buildImageSuccessfully(c, name, withBuildFlags(tc.buildflags...), withDockerfile(`FROM busybox
 	RUN echo hello world`))
 
-		containerCountAfter, err := getContainerCount()
-		if err != nil {
-			c.Fatalf("failed to get the container count: %s", err)
-		}
-
+		containerCountAfter := getContainerCount(c)
 		if tc.shouldLeftContainerBehind {
 			if containerCountBefore == containerCountAfter {
 				c.Fatalf("flags %v should have left containers behind", tc.buildflags)
@@ -2863,13 +2848,10 @@ func (s *DockerSuite) TestBuildAddTarXz(c *check.C) {
 			c.Fatalf("failed to close tar archive: %v", err)
 		}
 
-		xzCompressCmd := exec.Command("xz", "-k", "test.tar")
-		xzCompressCmd.Dir = tmpDir
-		out, _, err := runCommandWithOutput(xzCompressCmd)
-		if err != nil {
-			c.Fatal(err, out)
-		}
-
+		icmd.RunCmd(icmd.Cmd{
+			Command: []string{"xz", "-k", "test.tar"},
+			Dir:     tmpDir,
+		}).Assert(c, icmd.Success)
 		if err := ioutil.WriteFile(filepath.Join(tmpDir, "Dockerfile"), []byte(dockerfile), 0644); err != nil {
 			c.Fatalf("failed to open destination dockerfile: %v", err)
 		}
@@ -2913,20 +2895,15 @@ func (s *DockerSuite) TestBuildAddTarXzGz(c *check.C) {
 			c.Fatalf("failed to close tar archive: %v", err)
 		}
 
-		xzCompressCmd := exec.Command("xz", "-k", "test.tar")
-		xzCompressCmd.Dir = tmpDir
-		out, _, err := runCommandWithOutput(xzCompressCmd)
-		if err != nil {
-			c.Fatal(err, out)
-		}
-
-		gzipCompressCmd := exec.Command("gzip", "test.tar.xz")
-		gzipCompressCmd.Dir = tmpDir
-		out, _, err = runCommandWithOutput(gzipCompressCmd)
-		if err != nil {
-			c.Fatal(err, out)
-		}
+		icmd.RunCmd(icmd.Cmd{
+			Command: []string{"xz", "-k", "test.tar"},
+			Dir:     tmpDir,
+		}).Assert(c, icmd.Success)
 
+		icmd.RunCmd(icmd.Cmd{
+			Command: []string{"gzip", "test.tar.xz"},
+			Dir:     tmpDir,
+		})
 		if err := ioutil.WriteFile(filepath.Join(tmpDir, "Dockerfile"), []byte(dockerfile), 0644); err != nil {
 			c.Fatalf("failed to open destination dockerfile: %v", err)
 		}
@@ -5591,8 +5568,7 @@ func (s *DockerSuite) TestBuildSquashParent(c *check.C) {
 	dockerCmd(c, "run", "--rm", id, "/bin/sh", "-c", `[ "$(echo $HELLO)" == "world" ]`)
 
 	// make sure the ID produced is the ID of the tag we specified
-	inspectID, err := inspectImage("test", ".ID")
-	c.Assert(err, checker.IsNil)
+	inspectID := inspectImage(c, "test", ".ID")
 	c.Assert(inspectID, checker.Equals, id)
 
 	origHistory, _ := dockerCmd(c, "history", origID)
@@ -5602,8 +5578,7 @@ func (s *DockerSuite) TestBuildSquashParent(c *check.C) {
 	splitTestHistory := strings.Split(strings.TrimSpace(testHistory), "\n")
 	c.Assert(len(splitTestHistory), checker.Equals, len(splitOrigHistory)+1)
 
-	out, err = inspectImage(id, "len .RootFS.Layers")
-	c.Assert(err, checker.IsNil)
+	out = inspectImage(c, id, "len .RootFS.Layers")
 	c.Assert(strings.TrimSpace(out), checker.Equals, "3")
 }
 

integration-cli/docker_cli_cp_test.go

@@ -422,7 +422,7 @@ func (s *DockerSuite) TestCpSpecialFiles(c *check.C) {
 	// Copy actual /etc/resolv.conf
 	dockerCmd(c, "cp", containerID+":/etc/resolv.conf", outDir)
 
-	expected, err := readContainerFile(containerID, "resolv.conf")
+	expected := readContainerFile(c, containerID, "resolv.conf")
 	actual, err := ioutil.ReadFile(outDir + "/resolv.conf")
 
 	// Expected copied file to be duplicate of the container resolvconf
@@ -431,7 +431,7 @@ func (s *DockerSuite) TestCpSpecialFiles(c *check.C) {
 	// Copy actual /etc/hosts
 	dockerCmd(c, "cp", containerID+":/etc/hosts", outDir)
 
-	expected, err = readContainerFile(containerID, "hosts")
+	expected = readContainerFile(c, containerID, "hosts")
 	actual, err = ioutil.ReadFile(outDir + "/hosts")
 
 	// Expected copied file to be duplicate of the container hosts
@@ -440,7 +440,7 @@ func (s *DockerSuite) TestCpSpecialFiles(c *check.C) {
 	// Copy actual /etc/resolv.conf
 	dockerCmd(c, "cp", containerID+":/etc/hostname", outDir)
 
-	expected, err = readContainerFile(containerID, "hostname")
+	expected = readContainerFile(c, containerID, "hostname")
 	actual, err = ioutil.ReadFile(outDir + "/hostname")
 	c.Assert(err, checker.IsNil)
 

integration-cli/docker_cli_daemon_test.go

@@ -1951,11 +1951,11 @@ func (s *DockerDaemonSuite) TestDaemonRestartWithKilledRunningContainer(t *check
 
 	// Give time to containerd to process the command if we don't
 	// the exit event might be received after we do the inspect
-	pidCmd := exec.Command("kill", "-0", pid)
-	_, ec, _ := runCommandWithOutput(pidCmd)
-	for ec == 0 {
+	result := icmd.RunCommand("kill", "-0", pid)
+	for result.ExitCode == 0 {
 		time.Sleep(1 * time.Second)
-		_, ec, _ = runCommandWithOutput(pidCmd)
+		// FIXME(vdemeester) should we check it doesn't error out ?
+		result = icmd.RunCommand("kill", "-0", pid)
 	}
 
 	// restart the daemon

integration-cli/docker_cli_exec_test.go

@@ -389,8 +389,7 @@ func (s *DockerSuite) TestRunMutableNetworkFiles(c *check.C) {
 	for _, fn := range []string{"resolv.conf", "hosts"} {
 		deleteAllContainers(c)
 
-		content, err := runCommandAndReadContainerFile(fn, exec.Command(dockerBinary, "run", "-d", "--name", "c1", "busybox", "sh", "-c", fmt.Sprintf("echo success >/etc/%s && top", fn)))
-		c.Assert(err, checker.IsNil)
+		content := runCommandAndReadContainerFile(c, fn, dockerBinary, "run", "-d", "--name", "c1", "busybox", "sh", "-c", fmt.Sprintf("echo success >/etc/%s && top", fn))
 
 		c.Assert(strings.TrimSpace(string(content)), checker.Equals, "success", check.Commentf("Content was not what was modified in the container", string(content)))
 
@@ -442,30 +441,27 @@ func (s *DockerSuite) TestExecWithPrivileged(c *check.C) {
 	dockerCmd(c, "run", "-d", "--name", "parent", "--cap-drop=ALL", "busybox", "sh", "-c", `while (true); do if [ -e /exec_priv ]; then cat /exec_priv && mknod /tmp/sda b 8 0 && echo "Success"; else echo "Privileged exec has not run yet"; fi; usleep 10000; done`)
 
 	// Check exec mknod doesn't work
-	cmd := exec.Command(dockerBinary, "exec", "parent", "sh", "-c", "mknod /tmp/sdb b 8 16")
-	out, _, err := runCommandWithOutput(cmd)
-	c.Assert(err, checker.NotNil, check.Commentf("exec mknod in --cap-drop=ALL container without --privileged should fail"))
-	c.Assert(out, checker.Contains, "Operation not permitted", check.Commentf("exec mknod in --cap-drop=ALL container without --privileged should fail"))
+	icmd.RunCommand(dockerBinary, "exec", "parent", "sh", "-c", "mknod /tmp/sdb b 8 16").Assert(c, icmd.Expected{
+		ExitCode: 1,
+		Err:      "Operation not permitted",
+	})
 
 	// Check exec mknod does work with --privileged
-	cmd = exec.Command(dockerBinary, "exec", "--privileged", "parent", "sh", "-c", `echo "Running exec --privileged" > /exec_priv && mknod /tmp/sdb b 8 16 && usleep 50000 && echo "Finished exec --privileged" > /exec_priv && echo ok`)
-	out, _, err = runCommandWithOutput(cmd)
-	c.Assert(err, checker.IsNil)
+	result := icmd.RunCommand(dockerBinary, "exec", "--privileged", "parent", "sh", "-c", `echo "Running exec --privileged" > /exec_priv && mknod /tmp/sdb b 8 16 && usleep 50000 && echo "Finished exec --privileged" > /exec_priv && echo ok`)
+	result.Assert(c, icmd.Success)
 
-	actual := strings.TrimSpace(out)
-	c.Assert(actual, checker.Equals, "ok", check.Commentf("exec mknod in --cap-drop=ALL container with --privileged failed, output: %q", out))
+	actual := strings.TrimSpace(result.Combined())
+	c.Assert(actual, checker.Equals, "ok", check.Commentf("exec mknod in --cap-drop=ALL container with --privileged failed, output: %q", result.Combined()))
 
 	// Check subsequent unprivileged exec cannot mknod
-	cmd = exec.Command(dockerBinary, "exec", "parent", "sh", "-c", "mknod /tmp/sdc b 8 32")
-	out, _, err = runCommandWithOutput(cmd)
-	c.Assert(err, checker.NotNil, check.Commentf("repeating exec mknod in --cap-drop=ALL container after --privileged without --privileged should fail"))
-	c.Assert(out, checker.Contains, "Operation not permitted", check.Commentf("repeating exec mknod in --cap-drop=ALL container after --privileged without --privileged should fail"))
-
+	icmd.RunCommand(dockerBinary, "exec", "parent", "sh", "-c", "mknod /tmp/sdc b 8 32").Assert(c, icmd.Expected{
+		ExitCode: 1,
+		Err:      "Operation not permitted",
+	})
 	// Confirm at no point was mknod allowed
-	logCmd := exec.Command(dockerBinary, "logs", "parent")
-	out, _, err = runCommandWithOutput(logCmd)
-	c.Assert(err, checker.IsNil)
-	c.Assert(out, checker.Not(checker.Contains), "Success")
+	result = icmd.RunCommand(dockerBinary, "logs", "parent")
+	result.Assert(c, icmd.Success)
+	c.Assert(result.Combined(), checker.Not(checker.Contains), "Success")
 
 }
 

integration-cli/docker_cli_links_test.go

@@ -146,11 +146,8 @@ func (s *DockerSuite) TestLinksHostsFilesInject(c *check.C) {
 
 	c.Assert(waitRun(idTwo), checker.IsNil)
 
-	contentOne, err := readContainerFileWithExec(idOne, "/etc/hosts")
-	c.Assert(err, checker.IsNil, check.Commentf("contentOne: %s", string(contentOne)))
-
-	contentTwo, err := readContainerFileWithExec(idTwo, "/etc/hosts")
-	c.Assert(err, checker.IsNil, check.Commentf("contentTwo: %s", string(contentTwo)))
+	readContainerFileWithExec(c, idOne, "/etc/hosts")
+	contentTwo := readContainerFileWithExec(c, idTwo, "/etc/hosts")
 	// Host is not present in updated hosts file
 	c.Assert(string(contentTwo), checker.Contains, "onetwo")
 }
@@ -163,8 +160,7 @@ func (s *DockerSuite) TestLinksUpdateOnRestart(c *check.C) {
 	id := strings.TrimSpace(string(out))
 
 	realIP := inspectField(c, "one", "NetworkSettings.Networks.bridge.IPAddress")
-	content, err := readContainerFileWithExec(id, "/etc/hosts")
-	c.Assert(err, checker.IsNil)
+	content := readContainerFileWithExec(c, id, "/etc/hosts")
 
 	getIP := func(hosts []byte, hostname string) string {
 		re := regexp.MustCompile(fmt.Sprintf(`(\S*)\t%s`, regexp.QuoteMeta(hostname)))
@@ -181,8 +177,7 @@ func (s *DockerSuite) TestLinksUpdateOnRestart(c *check.C) {
 	dockerCmd(c, "restart", "one")
 	realIP = inspectField(c, "one", "NetworkSettings.Networks.bridge.IPAddress")
 
-	content, err = readContainerFileWithExec(id, "/etc/hosts")
-	c.Assert(err, checker.IsNil, check.Commentf("content: %s", string(content)))
+	content = readContainerFileWithExec(c, id, "/etc/hosts")
 	ip = getIP(content, "one")
 	c.Assert(ip, checker.Equals, realIP)
 

integration-cli/docker_cli_network_unix_test.go

@@ -869,18 +869,15 @@ func (s *DockerNetworkSuite) TestDockerNetworkAnonymousEndpoint(c *check.C) {
 	out, _ := dockerCmd(c, "run", "-d", "--net", cstmBridgeNw, "busybox", "top")
 	cid1 := strings.TrimSpace(out)
 
-	hosts1, err := readContainerFileWithExec(cid1, hostsFile)
-	c.Assert(err, checker.IsNil)
+	hosts1 := readContainerFileWithExec(c, cid1, hostsFile)
 
 	out, _ = dockerCmd(c, "run", "-d", "--net", cstmBridgeNw, "busybox", "top")
 	cid2 := strings.TrimSpace(out)
 
-	hosts2, err := readContainerFileWithExec(cid2, hostsFile)
-	c.Assert(err, checker.IsNil)
+	hosts2 := readContainerFileWithExec(c, cid2, hostsFile)
 
 	// verify first container etc/hosts file has not changed
-	hosts1post, err := readContainerFileWithExec(cid1, hostsFile)
-	c.Assert(err, checker.IsNil)
+	hosts1post := readContainerFileWithExec(c, cid1, hostsFile)
 	c.Assert(string(hosts1), checker.Equals, string(hosts1post),
 		check.Commentf("Unexpected %s change on anonymous container creation", hostsFile))
 
@@ -891,11 +888,8 @@ func (s *DockerNetworkSuite) TestDockerNetworkAnonymousEndpoint(c *check.C) {
 
 	dockerCmd(c, "network", "connect", cstmBridgeNw1, cid2)
 
-	hosts2, err = readContainerFileWithExec(cid2, hostsFile)
-	c.Assert(err, checker.IsNil)
-
-	hosts1post, err = readContainerFileWithExec(cid1, hostsFile)
-	c.Assert(err, checker.IsNil)
+	hosts2 = readContainerFileWithExec(c, cid2, hostsFile)
+	hosts1post = readContainerFileWithExec(c, cid1, hostsFile)
 	c.Assert(string(hosts1), checker.Equals, string(hosts1post),
 		check.Commentf("Unexpected %s change on container connect", hostsFile))
 
@@ -910,18 +904,16 @@ func (s *DockerNetworkSuite) TestDockerNetworkAnonymousEndpoint(c *check.C) {
 
 	// Stop named container and verify first two containers' etc/hosts file hasn't changed
 	dockerCmd(c, "stop", cid3)
-	hosts1post, err = readContainerFileWithExec(cid1, hostsFile)
-	c.Assert(err, checker.IsNil)
+	hosts1post = readContainerFileWithExec(c, cid1, hostsFile)
 	c.Assert(string(hosts1), checker.Equals, string(hosts1post),
 		check.Commentf("Unexpected %s change on name container creation", hostsFile))
 
-	hosts2post, err := readContainerFileWithExec(cid2, hostsFile)
-	c.Assert(err, checker.IsNil)
+	hosts2post := readContainerFileWithExec(c, cid2, hostsFile)
 	c.Assert(string(hosts2), checker.Equals, string(hosts2post),
 		check.Commentf("Unexpected %s change on name container creation", hostsFile))
 
 	// verify that container 1 and 2 can't ping the named container now
-	_, _, err = dockerCmdWithError("exec", cid1, "ping", "-c", "1", cName)
+	_, _, err := dockerCmdWithError("exec", cid1, "ping", "-c", "1", cName)
 	c.Assert(err, check.NotNil)
 	_, _, err = dockerCmdWithError("exec", cid2, "ping", "-c", "1", cName)
 	c.Assert(err, check.NotNil)

integration-cli/docker_cli_pause_test.go

@@ -15,8 +15,7 @@ func (s *DockerSuite) TestPause(c *check.C) {
 	runSleepingContainer(c, "-d", "--name", name)
 
 	dockerCmd(c, "pause", name)
-	pausedContainers, err := getPausedContainers()
-	c.Assert(err, checker.IsNil)
+	pausedContainers := getPausedContainers(c)
 	c.Assert(len(pausedContainers), checker.Equals, 1)
 
 	dockerCmd(c, "unpause", name)
@@ -41,8 +40,7 @@ func (s *DockerSuite) TestPauseMultipleContainers(c *check.C) {
 		runSleepingContainer(c, "-d", "--name", name)
 	}
 	dockerCmd(c, append([]string{"pause"}, containers...)...)
-	pausedContainers, err := getPausedContainers()
-	c.Assert(err, checker.IsNil)
+	pausedContainers := getPausedContainers(c)
 	c.Assert(len(pausedContainers), checker.Equals, len(containers))
 
 	dockerCmd(c, append([]string{"unpause"}, containers...)...)

integration-cli/docker_cli_ps_test.go

@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"sort"
 	"strconv"
@@ -159,12 +158,11 @@ func (s *DockerSuite) TestPsListContainersSize(c *check.C) {
 	dockerCmd(c, "run", "--name", name, "busybox", "sh", "-c", "echo 1 > test")
 	id := getIDByName(c, name)
 
-	runCmd := exec.Command(dockerBinary, "ps", "-s", "-n=1")
-	var out string
+	var result *icmd.Result
 
 	wait := make(chan struct{})
 	go func() {
-		out, _, err = runCommandWithOutput(runCmd)
+		result = icmd.RunCommand(dockerBinary, "ps", "-s", "-n=1")
 		close(wait)
 	}()
 	select {
@@ -172,8 +170,8 @@ func (s *DockerSuite) TestPsListContainersSize(c *check.C) {
 	case <-time.After(3 * time.Second):
 		c.Fatalf("Calling \"docker ps -s\" timed out!")
 	}
-	c.Assert(err, checker.IsNil)
-	lines := strings.Split(strings.Trim(out, "\n "), "\n")
+	result.Assert(c, icmd.Success)
+	lines := strings.Split(strings.Trim(result.Combined(), "\n "), "\n")
 	c.Assert(lines, checker.HasLen, 2, check.Commentf("Expected 2 lines for 'ps -s -n=1' output, got %d", len(lines)))
 	sizeIndex := strings.Index(lines[0], "SIZE")
 	idIndex := strings.Index(lines[0], "CONTAINER ID")

integration-cli/docker_cli_run_test.go

@@ -1464,10 +1464,7 @@ func (s *DockerSuite) TestRunResolvconfUpdate(c *check.C) {
 	dockerCmd(c, "start", "first")
 
 	// check for update in container
-	containerResolv, err := readContainerFile(containerID1, "resolv.conf")
-	if err != nil {
-		c.Fatal(err)
-	}
+	containerResolv := readContainerFile(c, containerID1, "resolv.conf")
 	if !bytes.Equal(containerResolv, bytesResolvConf) {
 		c.Fatalf("Restarted container does not have updated resolv.conf; expected %q, got %q", tmpResolvConf, string(containerResolv))
 	}
@@ -1490,11 +1487,7 @@ func (s *DockerSuite) TestRunResolvconfUpdate(c *check.C) {
 	dockerCmd(c, "start", "second")
 
 	// check for update in container
-	containerResolv, err = readContainerFile(containerID2, "resolv.conf")
-	if err != nil {
-		c.Fatal(err)
-	}
-
+	containerResolv = readContainerFile(c, containerID2, "resolv.conf")
 	if bytes.Equal(containerResolv, resolvConfSystem) {
 		c.Fatalf("Container's resolv.conf should not have been updated with host resolv.conf: %q", string(containerResolv))
 	}
@@ -1509,11 +1502,7 @@ func (s *DockerSuite) TestRunResolvconfUpdate(c *check.C) {
 	}
 
 	// check for update in container
-	containerResolv, err = readContainerFile(runningContainerID, "resolv.conf")
-	if err != nil {
-		c.Fatal(err)
-	}
-
+	containerResolv = readContainerFile(c, runningContainerID, "resolv.conf")
 	if bytes.Equal(containerResolv, bytesResolvConf) {
 		c.Fatalf("Running container should not have updated resolv.conf; expected %q, got %q", string(resolvConfSystem), string(containerResolv))
 	}
@@ -1523,10 +1512,7 @@ func (s *DockerSuite) TestRunResolvconfUpdate(c *check.C) {
 	dockerCmd(c, "restart", runningContainerID)
 
 	// check for update in container
-	containerResolv, err = readContainerFile(runningContainerID, "resolv.conf")
-	if err != nil {
-		c.Fatal(err)
-	}
+	containerResolv = readContainerFile(c, runningContainerID, "resolv.conf")
 	if !bytes.Equal(containerResolv, bytesResolvConf) {
 		c.Fatalf("Restarted container should have updated resolv.conf; expected %q, got %q", string(bytesResolvConf), string(containerResolv))
 	}
@@ -1545,11 +1531,7 @@ func (s *DockerSuite) TestRunResolvconfUpdate(c *check.C) {
 
 	// our first exited container ID should have been updated, but with default DNS
 	// after the cleanup of resolv.conf found only a localhost nameserver:
-	containerResolv, err = readContainerFile(containerID1, "resolv.conf")
-	if err != nil {
-		c.Fatal(err)
-	}
-
+	containerResolv = readContainerFile(c, containerID1, "resolv.conf")
 	expected := "\nnameserver 8.8.8.8\nnameserver 8.8.4.4\n"
 	if !bytes.Equal(containerResolv, []byte(expected)) {
 		c.Fatalf("Container does not have cleaned/replaced DNS in resolv.conf; expected %q, got %q", expected, string(containerResolv))
@@ -1582,10 +1564,7 @@ func (s *DockerSuite) TestRunResolvconfUpdate(c *check.C) {
 	dockerCmd(c, "start", "third")
 
 	// check for update in container
-	containerResolv, err = readContainerFile(containerID3, "resolv.conf")
-	if err != nil {
-		c.Fatal(err)
-	}
+	containerResolv = readContainerFile(c, containerID3, "resolv.conf")
 	if !bytes.Equal(containerResolv, bytesResolvConf) {
 		c.Fatalf("Stopped container does not have updated resolv.conf; expected\n%q\n got\n%q", tmpResolvConf, string(containerResolv))
 	}
@@ -2840,11 +2819,7 @@ func (s *DockerSuite) TestRunContainerWithRmFlagExitCodeNotEqualToZero(c *check.
 		c.Fatal("Expected docker run to fail", out, err)
 	}
 
-	out, err = getAllContainers()
-	if err != nil {
-		c.Fatal(out, err)
-	}
-
+	out = getAllContainers(c)
 	if out != "" {
 		c.Fatal("Expected not to have containers", out)
 	}
@@ -2857,11 +2832,7 @@ func (s *DockerSuite) TestRunContainerWithRmFlagCannotStartContainer(c *check.C)
 		c.Fatal("Expected docker run to fail", out, err)
 	}
 
-	out, err = getAllContainers()
-	if err != nil {
-		c.Fatal(out, err)
-	}
-
+	out = getAllContainers(c)
 	if out != "" {
 		c.Fatal("Expected not to have containers", out)
 	}

integration-cli/docker_cli_save_load_test.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/docker/docker/integration-cli/checker"
 	"github.com/docker/docker/pkg/testutil"
+	icmd "github.com/docker/docker/pkg/testutil/cmd"
 	"github.com/go-check/check"
 	"github.com/opencontainers/go-digest"
 )
@@ -37,10 +38,12 @@ func (s *DockerSuite) TestSaveXzAndLoadRepoStdout(c *check.C) {
 	c.Assert(err, checker.IsNil, check.Commentf("failed to save repo: %v %v", out, err))
 	deleteImages(repoName)
 
-	loadCmd := exec.Command(dockerBinary, "load")
-	loadCmd.Stdin = strings.NewReader(repoTarball)
-	out, _, err = runCommandWithOutput(loadCmd)
-	c.Assert(err, checker.NotNil, check.Commentf("expected error, but succeeded with no error and output: %v", out))
+	icmd.RunCmd(icmd.Cmd{
+		Command: []string{dockerBinary, "load"},
+		Stdin:   strings.NewReader(repoTarball),
+	}).Assert(c, icmd.Expected{
+		ExitCode: 1,
+	})
 
 	after, _, err := dockerCmdWithError("inspect", repoName)
 	c.Assert(err, checker.NotNil, check.Commentf("the repo should not exist: %v", after))
@@ -65,10 +68,12 @@ func (s *DockerSuite) TestSaveXzGzAndLoadRepoStdout(c *check.C) {
 
 	deleteImages(repoName)
 
-	loadCmd := exec.Command(dockerBinary, "load")
-	loadCmd.Stdin = strings.NewReader(out)
-	out, _, err = runCommandWithOutput(loadCmd)
-	c.Assert(err, checker.NotNil, check.Commentf("expected error, but succeeded with no error and output: %v", out))
+	icmd.RunCmd(icmd.Cmd{
+		Command: []string{dockerBinary, "load"},
+		Stdin:   strings.NewReader(out),
+	}).Assert(c, icmd.Expected{
+		ExitCode: 1,
+	})
 
 	after, _, err := dockerCmdWithError("inspect", repoName)
 	c.Assert(err, checker.NotNil, check.Commentf("the repo should not exist: %v", after))

integration-cli/docker_cli_save_load_unix_test.go

@@ -41,11 +41,10 @@ func (s *DockerSuite) TestSaveAndLoadRepoStdout(c *check.C) {
 
 	deleteImages(repoName)
 
-	loadCmd := exec.Command(dockerBinary, "load")
-	loadCmd.Stdin = tmpFile
-
-	out, _, err := runCommandWithOutput(loadCmd)
-	c.Assert(err, check.IsNil, check.Commentf(out))
+	icmd.RunCmd(icmd.Cmd{
+		Command: []string{dockerBinary, "load"},
+		Stdin:   tmpFile,
+	}).Assert(c, icmd.Success)
 
 	after := inspectField(c, repoName, "Id")
 	after = strings.TrimRight(after, "\n")
@@ -67,7 +66,7 @@ func (s *DockerSuite) TestSaveAndLoadRepoStdout(c *check.C) {
 
 	n, err := pty.Read(buf)
 	c.Assert(err, check.IsNil) //could not read tty output
-	c.Assert(string(buf[:n]), checker.Contains, "Cowardly refusing", check.Commentf("help output is not being yielded", out))
+	c.Assert(string(buf[:n]), checker.Contains, "Cowardly refusing", check.Commentf("help output is not being yielded"))
 }
 
 func (s *DockerSuite) TestSaveAndLoadWithProgressBar(c *check.C) {

integration-cli/docker_cli_swarm_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/docker/docker/api/types/swarm"
 	"github.com/docker/docker/integration-cli/checker"
 	"github.com/docker/docker/integration-cli/daemon"
+	icmd "github.com/docker/docker/pkg/testutil/cmd"
 	"github.com/docker/libnetwork/driverapi"
 	"github.com/docker/libnetwork/ipamapi"
 	remoteipam "github.com/docker/libnetwork/ipams/remote/api"
@@ -832,8 +833,7 @@ func checkSwarmLockedToUnlocked(c *check.C, d *daemon.Swarm, unlockKey string) {
 		// it must not have updated to be unlocked in time - unlock, wait 3 seconds, and try again
 		cmd := d.Command("swarm", "unlock")
 		cmd.Stdin = bytes.NewBufferString(unlockKey)
-		out, err := cmd.CombinedOutput()
-		c.Assert(err, checker.IsNil, check.Commentf("out: %v", string(out)))
+		icmd.RunCmd(cmd).Assert(c, icmd.Success)
 
 		c.Assert(getNodeStatus(c, d), checker.Equals, swarm.LocalNodeStateActive)
 
@@ -860,22 +860,24 @@ func (s *DockerSwarmSuite) TestUnlockEngineAndUnlockedSwarm(c *check.C) {
 
 	// unlocking a normal engine should return an error - it does not even ask for the key
 	cmd := d.Command("swarm", "unlock")
-	outs, err := cmd.CombinedOutput()
-
-	c.Assert(err, checker.NotNil, check.Commentf("out: %v", string(outs)))
-	c.Assert(string(outs), checker.Contains, "Error: This node is not part of a swarm")
-	c.Assert(string(outs), checker.Not(checker.Contains), "Please enter unlock key")
+	result := icmd.RunCmd(cmd)
+	result.Assert(c, icmd.Expected{
+		ExitCode: 1,
+	})
+	c.Assert(result.Combined(), checker.Contains, "Error: This node is not part of a swarm")
+	c.Assert(result.Combined(), checker.Not(checker.Contains), "Please enter unlock key")
 
-	_, err = d.Cmd("swarm", "init")
+	_, err := d.Cmd("swarm", "init")
 	c.Assert(err, checker.IsNil)
 
 	// unlocking an unlocked swarm should return an error - it does not even ask for the key
 	cmd = d.Command("swarm", "unlock")
-	outs, err = cmd.CombinedOutput()
-
-	c.Assert(err, checker.NotNil, check.Commentf("out: %v", string(outs)))
-	c.Assert(string(outs), checker.Contains, "Error: swarm is not locked")
-	c.Assert(string(outs), checker.Not(checker.Contains), "Please enter unlock key")
+	result = icmd.RunCmd(cmd)
+	result.Assert(c, icmd.Expected{
+		ExitCode: 1,
+	})
+	c.Assert(result.Combined(), checker.Contains, "Error: swarm is not locked")
+	c.Assert(result.Combined(), checker.Not(checker.Contains), "Please enter unlock key")
 }
 
 func (s *DockerSwarmSuite) TestSwarmInitLocked(c *check.C) {
@@ -907,16 +909,16 @@ func (s *DockerSwarmSuite) TestSwarmInitLocked(c *check.C) {
 
 	cmd := d.Command("swarm", "unlock")
 	cmd.Stdin = bytes.NewBufferString("wrong-secret-key")
-	out, err := cmd.CombinedOutput()
-	c.Assert(err, checker.NotNil, check.Commentf("out: %v", string(out)))
-	c.Assert(string(out), checker.Contains, "invalid key")
+	icmd.RunCmd(cmd).Assert(c, icmd.Expected{
+		ExitCode: 1,
+		Err:      "invalid key",
+	})
 
 	c.Assert(getNodeStatus(c, d), checker.Equals, swarm.LocalNodeStateLocked)
 
 	cmd = d.Command("swarm", "unlock")
 	cmd.Stdin = bytes.NewBufferString(unlockKey)
-	out, err = cmd.CombinedOutput()
-	c.Assert(err, checker.IsNil, check.Commentf("out: %v", string(out)))
+	icmd.RunCmd(cmd).Assert(c, icmd.Success)
 
 	c.Assert(getNodeStatus(c, d), checker.Equals, swarm.LocalNodeStateActive)
 
@@ -1007,8 +1009,7 @@ func (s *DockerSwarmSuite) TestSwarmLockUnlockCluster(c *check.C) {
 
 		cmd := d.Command("swarm", "unlock")
 		cmd.Stdin = bytes.NewBufferString(unlockKey)
-		out, err := cmd.CombinedOutput()
-		c.Assert(err, checker.IsNil, check.Commentf("out: %v", string(out)))
+		icmd.RunCmd(cmd).Assert(c, icmd.Success)
 		c.Assert(getNodeStatus(c, d), checker.Equals, swarm.LocalNodeStateActive)
 	}
 
@@ -1034,8 +1035,7 @@ func (s *DockerSwarmSuite) TestSwarmLockUnlockCluster(c *check.C) {
 	// unlock it
 	cmd := d2.Command("swarm", "unlock")
 	cmd.Stdin = bytes.NewBufferString(unlockKey)
-	out, err := cmd.CombinedOutput()
-	c.Assert(err, checker.IsNil, check.Commentf("out: %v", string(out)))
+	icmd.RunCmd(cmd).Assert(c, icmd.Success)
 	c.Assert(getNodeStatus(c, d2), checker.Equals, swarm.LocalNodeStateActive)
 
 	// once it's caught up, d2 is set to not be locked
@@ -1088,8 +1088,7 @@ func (s *DockerSwarmSuite) TestSwarmJoinPromoteLocked(c *check.C) {
 
 		cmd := d.Command("swarm", "unlock")
 		cmd.Stdin = bytes.NewBufferString(unlockKey)
-		out, err := cmd.CombinedOutput()
-		c.Assert(err, checker.IsNil, check.Commentf("out: %v", string(out)))
+		icmd.RunCmd(cmd).Assert(c, icmd.Success)
 		c.Assert(getNodeStatus(c, d), checker.Equals, swarm.LocalNodeStateActive)
 	}
 
@@ -1159,9 +1158,9 @@ func (s *DockerSwarmSuite) TestSwarmRotateUnlockKey(c *check.C) {
 
 		cmd := d.Command("swarm", "unlock")
 		cmd.Stdin = bytes.NewBufferString(unlockKey)
-		out, err := cmd.CombinedOutput()
+		result := icmd.RunCmd(cmd)
 
-		if err == nil {
+		if result.Error == nil {
 			// On occasion, the daemon may not have finished
 			// rotating the KEK before restarting. The test is
 			// intentionally written to explore this behavior.
@@ -1176,18 +1175,19 @@ func (s *DockerSwarmSuite) TestSwarmRotateUnlockKey(c *check.C) {
 
 			cmd = d.Command("swarm", "unlock")
 			cmd.Stdin = bytes.NewBufferString(unlockKey)
-			out, err = cmd.CombinedOutput()
+			result = icmd.RunCmd(cmd)
 		}
-		c.Assert(err, checker.NotNil, check.Commentf("out: %v", string(out)))
-		c.Assert(string(out), checker.Contains, "invalid key")
+		result.Assert(c, icmd.Expected{
+			ExitCode: 1,
+			Err:      "invalid key",
+		})
 
 		outs, _ = d.Cmd("node", "ls")
 		c.Assert(outs, checker.Contains, "Swarm is encrypted and needs to be unlocked")
 
 		cmd = d.Command("swarm", "unlock")
 		cmd.Stdin = bytes.NewBufferString(newUnlockKey)
-		out, err = cmd.CombinedOutput()
-		c.Assert(err, checker.IsNil, check.Commentf("out: %v", string(out)))
+		icmd.RunCmd(cmd).Assert(c, icmd.Success)
 
 		c.Assert(getNodeStatus(c, d), checker.Equals, swarm.LocalNodeStateActive)
 
@@ -1245,9 +1245,9 @@ func (s *DockerSwarmSuite) TestSwarmClusterRotateUnlockKey(c *check.C) {
 
 			cmd := d.Command("swarm", "unlock")
 			cmd.Stdin = bytes.NewBufferString(unlockKey)
-			out, err := cmd.CombinedOutput()
+			result := icmd.RunCmd(cmd)
 
-			if err == nil {
+			if result.Error == nil {
 				// On occasion, the daemon may not have finished
 				// rotating the KEK before restarting. The test is
 				// intentionally written to explore this behavior.
@@ -1262,18 +1262,19 @@ func (s *DockerSwarmSuite) TestSwarmClusterRotateUnlockKey(c *check.C) {
 
 				cmd = d.Command("swarm", "unlock")
 				cmd.Stdin = bytes.NewBufferString(unlockKey)
-				out, err = cmd.CombinedOutput()
+				result = icmd.RunCmd(cmd)
 			}
-			c.Assert(err, checker.NotNil, check.Commentf("out: %v", string(out)))
-			c.Assert(string(out), checker.Contains, "invalid key")
+			result.Assert(c, icmd.Expected{
+				ExitCode: 1,
+				Err:      "invalid key",
+			})
 
 			outs, _ = d.Cmd("node", "ls")
 			c.Assert(outs, checker.Contains, "Swarm is encrypted and needs to be unlocked")
 
 			cmd = d.Command("swarm", "unlock")
 			cmd.Stdin = bytes.NewBufferString(newUnlockKey)
-			out, err = cmd.CombinedOutput()
-			c.Assert(err, checker.IsNil, check.Commentf("out: %v", string(out)))
+			icmd.RunCmd(cmd).Assert(c, icmd.Success)
 
 			c.Assert(getNodeStatus(c, d), checker.Equals, swarm.LocalNodeStateActive)
 
@@ -1308,8 +1309,7 @@ func (s *DockerSwarmSuite) TestSwarmAlternateLockUnlock(c *check.C) {
 
 		cmd := d.Command("swarm", "unlock")
 		cmd.Stdin = bytes.NewBufferString(unlockKey)
-		out, err := cmd.CombinedOutput()
-		c.Assert(err, checker.IsNil, check.Commentf("out: %v", string(out)))
+		icmd.RunCmd(cmd).Assert(c, icmd.Success)
 
 		c.Assert(getNodeStatus(c, d), checker.Equals, swarm.LocalNodeStateActive)
 
@@ -1410,12 +1410,11 @@ func (s *DockerTrustedSwarmSuite) TestTrustedServiceCreate(c *check.C) {
 
 	name := "trusted"
 	serviceCmd := d.Command("-D", "service", "create", "--name", name, repoName, "top")
-	trustedExecCmd(serviceCmd)
-	out, _, err := runCommandWithOutput(serviceCmd)
-	c.Assert(err, checker.IsNil, check.Commentf(out))
-	c.Assert(out, checker.Contains, "resolved image tag to", check.Commentf(out))
+	icmd.RunCmd(serviceCmd, trustedCmd).Assert(c, icmd.Expected{
+		Err: "resolved image tag to",
+	})
 
-	out, err = d.Cmd("service", "inspect", "--pretty", name)
+	out, err := d.Cmd("service", "inspect", "--pretty", name)
 	c.Assert(err, checker.IsNil, check.Commentf(out))
 	c.Assert(out, checker.Contains, repoName+"@", check.Commentf(out))
 
@@ -1429,11 +1428,10 @@ func (s *DockerTrustedSwarmSuite) TestTrustedServiceCreate(c *check.C) {
 
 	name = "untrusted"
 	serviceCmd = d.Command("service", "create", "--name", name, repoName, "top")
-	trustedExecCmd(serviceCmd)
-	out, _, err = runCommandWithOutput(serviceCmd)
-
-	c.Assert(err, check.NotNil, check.Commentf(out))
-	c.Assert(string(out), checker.Contains, "Error: remote trust data does not exist", check.Commentf(out))
+	icmd.RunCmd(serviceCmd, trustedCmd).Assert(c, icmd.Expected{
+		ExitCode: 1,
+		Err:      "Error: remote trust data does not exist",
+	})
 
 	out, err = d.Cmd("service", "inspect", "--pretty", name)
 	c.Assert(err, checker.NotNil, check.Commentf(out))
@@ -1458,10 +1456,9 @@ func (s *DockerTrustedSwarmSuite) TestTrustedServiceUpdate(c *check.C) {
 	c.Assert(out, check.Not(checker.Contains), repoName+"@", check.Commentf(out))
 
 	serviceCmd := d.Command("-D", "service", "update", "--image", repoName, name)
-	trustedExecCmd(serviceCmd)
-	out, _, err = runCommandWithOutput(serviceCmd)
-	c.Assert(err, checker.IsNil, check.Commentf(out))
-	c.Assert(out, checker.Contains, "resolved image tag to", check.Commentf(out))
+	icmd.RunCmd(serviceCmd, trustedCmd).Assert(c, icmd.Expected{
+		Err: "resolved image tag to",
+	})
 
 	out, err = d.Cmd("service", "inspect", "--pretty", name)
 	c.Assert(err, checker.IsNil, check.Commentf(out))
@@ -1476,11 +1473,10 @@ func (s *DockerTrustedSwarmSuite) TestTrustedServiceUpdate(c *check.C) {
 	dockerCmd(c, "rmi", repoName)
 
 	serviceCmd = d.Command("service", "update", "--image", repoName, name)
-	trustedExecCmd(serviceCmd)
-	out, _, err = runCommandWithOutput(serviceCmd)
-
-	c.Assert(err, check.NotNil, check.Commentf(out))
-	c.Assert(string(out), checker.Contains, "Error: remote trust data does not exist", check.Commentf(out))
+	icmd.RunCmd(serviceCmd, trustedCmd).Assert(c, icmd.Expected{
+		ExitCode: 1,
+		Err:      "Error: remote trust data does not exist",
+	})
 }
 
 // Test case for issue #27866, which did not allow NW name that is the prefix of a swarm NW ID.

integration-cli/docker_utils_test.go

@@ -52,22 +52,16 @@ func deleteContainer(ignoreNoSuchContainer bool, container ...string) error {
 	return result.Compare(icmd.Success)
 }
 
-func getAllContainers() (string, error) {
-	getContainersCmd := exec.Command(dockerBinary, "ps", "-q", "-a")
-	out, exitCode, err := runCommandWithOutput(getContainersCmd)
-	if exitCode != 0 && err == nil {
-		err = fmt.Errorf("failed to get a list of containers: %v\n", out)
-	}
-
-	return out, err
+func getAllContainers(c *check.C) string {
+	result := icmd.RunCommand(dockerBinary, "ps", "-q", "-a")
+	result.Assert(c, icmd.Success)
+	return result.Combined()
 }
 
 func deleteAllContainers(c *check.C) {
-	containers, err := getAllContainers()
-	c.Assert(err, checker.IsNil, check.Commentf("containers: %v", containers))
-
+	containers := getAllContainers(c)
 	if containers != "" {
-		err = deleteContainer(true, strings.Split(strings.TrimSpace(containers), "\n")...)
+		err := deleteContainer(true, strings.Split(strings.TrimSpace(containers), "\n")...)
 		c.Assert(err, checker.IsNil)
 	}
 }
@@ -202,17 +196,10 @@ func deleteAllImages(c *check.C) {
 	}
 }
 
-func getPausedContainers() ([]string, error) {
-	getPausedContainersCmd := exec.Command(dockerBinary, "ps", "-f", "status=paused", "-q", "-a")
-	out, exitCode, err := runCommandWithOutput(getPausedContainersCmd)
-	if exitCode != 0 && err == nil {
-		err = fmt.Errorf("failed to get a list of paused containers: %v\n", out)
-	}
-	if err != nil {
-		return nil, err
-	}
-
-	return strings.Fields(out), nil
+func getPausedContainers(c *check.C) []string {
+	result := icmd.RunCommand(dockerBinary, "ps", "-f", "status=paused", "-q", "-a")
+	result.Assert(c, icmd.Success)
+	return strings.Fields(result.Combined())
 }
 
 func unpauseContainer(c *check.C, container string) {
@@ -220,8 +207,7 @@ func unpauseContainer(c *check.C, container string) {
 }
 
 func unpauseAllContainers(c *check.C) {
-	containers, err := getPausedContainers()
-	c.Assert(err, checker.IsNil, check.Commentf("containers: %v", containers))
+	containers := getPausedContainers(c)
 	for _, value := range containers {
 		unpauseContainer(c, value)
 	}
@@ -310,29 +296,24 @@ func findContainerIP(c *check.C, id string, network string) string {
 	return strings.Trim(out, " \r\n'")
 }
 
-func getContainerCount() (int, error) {
+func getContainerCount(c *check.C) int {
 	const containers = "Containers:"
 
-	cmd := exec.Command(dockerBinary, "info")
-	out, _, err := runCommandWithOutput(cmd)
-	if err != nil {
-		return 0, err
-	}
+	result := icmd.RunCommand(dockerBinary, "info")
+	result.Assert(c, icmd.Success)
 
-	lines := strings.Split(out, "\n")
+	lines := strings.Split(result.Combined(), "\n")
 	for _, line := range lines {
 		if strings.Contains(line, containers) {
 			output := strings.TrimSpace(line)
 			output = strings.TrimLeft(output, containers)
 			output = strings.Trim(output, " ")
 			containerCount, err := strconv.Atoi(output)
-			if err != nil {
-				return 0, err
-			}
-			return containerCount, nil
+			c.Assert(err, checker.IsNil)
+			return containerCount
 		}
 	}
-	return 0, fmt.Errorf("couldn't find the Container count in the output")
+	return 0
 }
 
 // FakeContext creates directories that can be used as a build context
@@ -626,19 +607,16 @@ func inspectMountPointJSON(j, destination string) (types.MountPoint, error) {
 	return *m, nil
 }
 
-func inspectImage(name, filter string) (string, error) {
+func inspectImage(c *check.C, name, filter string) string {
 	args := []string{"inspect", "--type", "image"}
 	if filter != "" {
 		format := fmt.Sprintf("{{%s}}", filter)
 		args = append(args, "-f", format)
 	}
 	args = append(args, name)
-	inspectCmd := exec.Command(dockerBinary, args...)
-	out, exitCode, err := runCommandWithOutput(inspectCmd)
-	if err != nil || exitCode != 0 {
-		return "", fmt.Errorf("failed to inspect %s: %s", name, out)
-	}
-	return strings.TrimSpace(out), nil
+	result := icmd.RunCommand(dockerBinary, args...)
+	result.Assert(c, icmd.Success)
+	return strings.TrimSpace(result.Combined())
 }
 
 func getIDByName(c *check.C, name string) string {
@@ -864,39 +842,30 @@ func containerStorageFile(containerID, basename string) string {
 }
 
 // docker commands that use this function must be run with the '-d' switch.
-func runCommandAndReadContainerFile(filename string, cmd *exec.Cmd) ([]byte, error) {
-	out, _, err := runCommandWithOutput(cmd)
-	if err != nil {
-		return nil, fmt.Errorf("%v: %q", err, out)
-	}
-
-	contID := strings.TrimSpace(out)
-
+func runCommandAndReadContainerFile(c *check.C, filename string, command string, args ...string) []byte {
+	result := icmd.RunCommand(command, args...)
+	result.Assert(c, icmd.Success)
+	contID := strings.TrimSpace(result.Combined())
 	if err := waitRun(contID); err != nil {
-		return nil, fmt.Errorf("%v: %q", contID, err)
+		c.Fatalf("%v: %q", contID, err)
 	}
-
-	return readContainerFile(contID, filename)
+	return readContainerFile(c, contID, filename)
 }
 
-func readContainerFile(containerID, filename string) ([]byte, error) {
+func readContainerFile(c *check.C, containerID, filename string) []byte {
 	f, err := os.Open(containerStorageFile(containerID, filename))
-	if err != nil {
-		return nil, err
-	}
+	c.Assert(err, checker.IsNil)
 	defer f.Close()
 
 	content, err := ioutil.ReadAll(f)
-	if err != nil {
-		return nil, err
-	}
-
-	return content, nil
+	c.Assert(err, checker.IsNil)
+	return content
 }
 
-func readContainerFileWithExec(containerID, filename string) ([]byte, error) {
-	out, _, err := runCommandWithOutput(exec.Command(dockerBinary, "exec", containerID, "cat", filename))
-	return []byte(out), err
+func readContainerFileWithExec(c *check.C, containerID, filename string) []byte {
+	result := icmd.RunCommand(dockerBinary, "exec", containerID, "cat", filename)
+	result.Assert(c, icmd.Success)
+	return []byte(result.Combined())
 }
 
 // daemonTime provides the current time on the daemon host