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moby--moby/integration-cli/docker_cli_by_digest_test.go
Zhang Wei 62a856e912 Assert error in body of function inspectField*
1. Replace raw `docker inspect -f xxx` with `inspectField`, to make code
cleaner and more consistent
2. assert the error in function `inspectField*` so we don't need to
assert the return value of it every time, this will make inspect easier.

Signed-off-by: Zhang Wei <zhangwei555@huawei.com>
2016-01-29 23:39:07 +08:00

583 lines
22 KiB
Go

package main
import (
"encoding/json"
"fmt"
"os"
"path/filepath"
"regexp"
"strings"
"github.com/docker/distribution/digest"
"github.com/docker/distribution/manifest/schema1"
"github.com/docker/distribution/manifest/schema2"
"github.com/docker/docker/pkg/integration/checker"
"github.com/docker/docker/pkg/stringutils"
"github.com/docker/engine-api/types"
"github.com/go-check/check"
)
var (
remoteRepoName = "dockercli/busybox-by-dgst"
repoName = fmt.Sprintf("%s/%s", privateRegistryURL, remoteRepoName)
pushDigestRegex = regexp.MustCompile("[\\S]+: digest: ([\\S]+) size: [0-9]+")
digestRegex = regexp.MustCompile("Digest: ([\\S]+)")
)
func setupImage(c *check.C) (digest.Digest, error) {
return setupImageWithTag(c, "latest")
}
func setupImageWithTag(c *check.C, tag string) (digest.Digest, error) {
containerName := "busyboxbydigest"
dockerCmd(c, "run", "-d", "-e", "digest=1", "--name", containerName, "busybox")
// tag the image to upload it to the private registry
repoAndTag := repoName + ":" + tag
out, _, err := dockerCmdWithError("commit", containerName, repoAndTag)
c.Assert(err, checker.IsNil, check.Commentf("image tagging failed: %s", out))
// delete the container as we don't need it any more
err = deleteContainer(containerName)
c.Assert(err, checker.IsNil)
// push the image
out, _, err = dockerCmdWithError("push", repoAndTag)
c.Assert(err, checker.IsNil, check.Commentf("pushing the image to the private registry has failed: %s", out))
// delete our local repo that we previously tagged
rmiout, _, err := dockerCmdWithError("rmi", repoAndTag)
c.Assert(err, checker.IsNil, check.Commentf("error deleting images prior to real test: %s", rmiout))
matches := pushDigestRegex.FindStringSubmatch(out)
c.Assert(matches, checker.HasLen, 2, check.Commentf("unable to parse digest from push output: %s", out))
pushDigest := matches[1]
return digest.Digest(pushDigest), nil
}
func testPullByTagDisplaysDigest(c *check.C) {
testRequires(c, DaemonIsLinux)
pushDigest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
// pull from the registry using the tag
out, _ := dockerCmd(c, "pull", repoName)
// the pull output includes "Digest: <digest>", so find that
matches := digestRegex.FindStringSubmatch(out)
c.Assert(matches, checker.HasLen, 2, check.Commentf("unable to parse digest from pull output: %s", out))
pullDigest := matches[1]
// make sure the pushed and pull digests match
c.Assert(pushDigest.String(), checker.Equals, pullDigest)
}
func (s *DockerRegistrySuite) TestPullByTagDisplaysDigest(c *check.C) {
testPullByTagDisplaysDigest(c)
}
func (s *DockerSchema1RegistrySuite) TestPullByTagDisplaysDigest(c *check.C) {
testPullByTagDisplaysDigest(c)
}
func testPullByDigest(c *check.C) {
testRequires(c, DaemonIsLinux)
pushDigest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
// pull from the registry using the <name>@<digest> reference
imageReference := fmt.Sprintf("%s@%s", repoName, pushDigest)
out, _ := dockerCmd(c, "pull", imageReference)
// the pull output includes "Digest: <digest>", so find that
matches := digestRegex.FindStringSubmatch(out)
c.Assert(matches, checker.HasLen, 2, check.Commentf("unable to parse digest from pull output: %s", out))
pullDigest := matches[1]
// make sure the pushed and pull digests match
c.Assert(pushDigest.String(), checker.Equals, pullDigest)
}
func (s *DockerRegistrySuite) TestPullByDigest(c *check.C) {
testPullByDigest(c)
}
func (s *DockerSchema1RegistrySuite) TestPullByDigest(c *check.C) {
testPullByDigest(c)
}
func testPullByDigestNoFallback(c *check.C) {
testRequires(c, DaemonIsLinux)
// pull from the registry using the <name>@<digest> reference
imageReference := fmt.Sprintf("%s@sha256:ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff", repoName)
out, _, err := dockerCmdWithError("pull", imageReference)
c.Assert(err, checker.NotNil, check.Commentf("expected non-zero exit status and correct error message when pulling non-existing image"))
c.Assert(out, checker.Contains, "manifest unknown", check.Commentf("expected non-zero exit status and correct error message when pulling non-existing image"))
}
func (s *DockerRegistrySuite) TestPullByDigestNoFallback(c *check.C) {
testPullByDigestNoFallback(c)
}
func (s *DockerSchema1RegistrySuite) TestPullByDigestNoFallback(c *check.C) {
testPullByDigestNoFallback(c)
}
func (s *DockerRegistrySuite) TestCreateByDigest(c *check.C) {
pushDigest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
imageReference := fmt.Sprintf("%s@%s", repoName, pushDigest)
containerName := "createByDigest"
dockerCmd(c, "create", "--name", containerName, imageReference)
res := inspectField(c, containerName, "Config.Image")
c.Assert(res, checker.Equals, imageReference)
}
func (s *DockerRegistrySuite) TestRunByDigest(c *check.C) {
pushDigest, err := setupImage(c)
c.Assert(err, checker.IsNil)
imageReference := fmt.Sprintf("%s@%s", repoName, pushDigest)
containerName := "runByDigest"
out, _ := dockerCmd(c, "run", "--name", containerName, imageReference, "sh", "-c", "echo found=$digest")
foundRegex := regexp.MustCompile("found=([^\n]+)")
matches := foundRegex.FindStringSubmatch(out)
c.Assert(matches, checker.HasLen, 2, check.Commentf("unable to parse digest from pull output: %s", out))
c.Assert(matches[1], checker.Equals, "1", check.Commentf("Expected %q, got %q", "1", matches[1]))
res := inspectField(c, containerName, "Config.Image")
c.Assert(res, checker.Equals, imageReference)
}
func (s *DockerRegistrySuite) TestRemoveImageByDigest(c *check.C) {
digest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
imageReference := fmt.Sprintf("%s@%s", repoName, digest)
// pull from the registry using the <name>@<digest> reference
dockerCmd(c, "pull", imageReference)
// make sure inspect runs ok
inspectField(c, imageReference, "Id")
// do the delete
err = deleteImages(imageReference)
c.Assert(err, checker.IsNil, check.Commentf("unexpected error deleting image"))
// try to inspect again - it should error this time
_, err = inspectFieldWithError(imageReference, "Id")
//unexpected nil err trying to inspect what should be a non-existent image
c.Assert(err, checker.NotNil)
c.Assert(err.Error(), checker.Contains, "No such image")
}
func (s *DockerRegistrySuite) TestBuildByDigest(c *check.C) {
digest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
imageReference := fmt.Sprintf("%s@%s", repoName, digest)
// pull from the registry using the <name>@<digest> reference
dockerCmd(c, "pull", imageReference)
// get the image id
imageID := inspectField(c, imageReference, "Id")
// do the build
name := "buildbydigest"
_, err = buildImage(name, fmt.Sprintf(
`FROM %s
CMD ["/bin/echo", "Hello World"]`, imageReference),
true)
c.Assert(err, checker.IsNil)
// get the build's image id
res := inspectField(c, name, "Config.Image")
// make sure they match
c.Assert(res, checker.Equals, imageID)
}
func (s *DockerRegistrySuite) TestTagByDigest(c *check.C) {
digest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
imageReference := fmt.Sprintf("%s@%s", repoName, digest)
// pull from the registry using the <name>@<digest> reference
dockerCmd(c, "pull", imageReference)
// tag it
tag := "tagbydigest"
dockerCmd(c, "tag", imageReference, tag)
expectedID := inspectField(c, imageReference, "Id")
tagID := inspectField(c, tag, "Id")
c.Assert(tagID, checker.Equals, expectedID)
}
func (s *DockerRegistrySuite) TestListImagesWithoutDigests(c *check.C) {
digest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
imageReference := fmt.Sprintf("%s@%s", repoName, digest)
// pull from the registry using the <name>@<digest> reference
dockerCmd(c, "pull", imageReference)
out, _ := dockerCmd(c, "images")
c.Assert(out, checker.Not(checker.Contains), "DIGEST", check.Commentf("list output should not have contained DIGEST header"))
}
func (s *DockerRegistrySuite) TestListImagesWithDigests(c *check.C) {
// setup image1
digest1, err := setupImageWithTag(c, "tag1")
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
imageReference1 := fmt.Sprintf("%s@%s", repoName, digest1)
c.Logf("imageReference1 = %s", imageReference1)
// pull image1 by digest
dockerCmd(c, "pull", imageReference1)
// list images
out, _ := dockerCmd(c, "images", "--digests")
// make sure repo shown, tag=<none>, digest = $digest1
re1 := regexp.MustCompile(`\s*` + repoName + `\s*<none>\s*` + digest1.String() + `\s`)
c.Assert(re1.MatchString(out), checker.True, check.Commentf("expected %q: %s", re1.String(), out))
// setup image2
digest2, err := setupImageWithTag(c, "tag2")
//error setting up image
c.Assert(err, checker.IsNil)
imageReference2 := fmt.Sprintf("%s@%s", repoName, digest2)
c.Logf("imageReference2 = %s", imageReference2)
// pull image1 by digest
dockerCmd(c, "pull", imageReference1)
// pull image2 by digest
dockerCmd(c, "pull", imageReference2)
// list images
out, _ = dockerCmd(c, "images", "--digests")
// make sure repo shown, tag=<none>, digest = $digest1
c.Assert(re1.MatchString(out), checker.True, check.Commentf("expected %q: %s", re1.String(), out))
// make sure repo shown, tag=<none>, digest = $digest2
re2 := regexp.MustCompile(`\s*` + repoName + `\s*<none>\s*` + digest2.String() + `\s`)
c.Assert(re2.MatchString(out), checker.True, check.Commentf("expected %q: %s", re2.String(), out))
// pull tag1
dockerCmd(c, "pull", repoName+":tag1")
// list images
out, _ = dockerCmd(c, "images", "--digests")
// make sure image 1 has repo, tag, <none> AND repo, <none>, digest
reWithTag1 := regexp.MustCompile(`\s*` + repoName + `\s*tag1\s*<none>\s`)
reWithDigest1 := regexp.MustCompile(`\s*` + repoName + `\s*<none>\s*` + digest1.String() + `\s`)
c.Assert(reWithDigest1.MatchString(out), checker.True, check.Commentf("expected %q: %s", reWithDigest1.String(), out))
c.Assert(reWithTag1.MatchString(out), checker.True, check.Commentf("expected %q: %s", reWithTag1.String(), out))
// make sure image 2 has repo, <none>, digest
c.Assert(re2.MatchString(out), checker.True, check.Commentf("expected %q: %s", re2.String(), out))
// pull tag 2
dockerCmd(c, "pull", repoName+":tag2")
// list images
out, _ = dockerCmd(c, "images", "--digests")
// make sure image 1 has repo, tag, digest
c.Assert(reWithTag1.MatchString(out), checker.True, check.Commentf("expected %q: %s", reWithTag1.String(), out))
// make sure image 2 has repo, tag, digest
reWithTag2 := regexp.MustCompile(`\s*` + repoName + `\s*tag2\s*<none>\s`)
reWithDigest2 := regexp.MustCompile(`\s*` + repoName + `\s*<none>\s*` + digest2.String() + `\s`)
c.Assert(reWithTag2.MatchString(out), checker.True, check.Commentf("expected %q: %s", reWithTag2.String(), out))
c.Assert(reWithDigest2.MatchString(out), checker.True, check.Commentf("expected %q: %s", reWithDigest2.String(), out))
// list images
out, _ = dockerCmd(c, "images", "--digests")
// make sure image 1 has repo, tag, digest
c.Assert(reWithTag1.MatchString(out), checker.True, check.Commentf("expected %q: %s", reWithTag1.String(), out))
// make sure image 2 has repo, tag, digest
c.Assert(reWithTag2.MatchString(out), checker.True, check.Commentf("expected %q: %s", reWithTag2.String(), out))
// make sure busybox has tag, but not digest
busyboxRe := regexp.MustCompile(`\s*busybox\s*latest\s*<none>\s`)
c.Assert(busyboxRe.MatchString(out), checker.True, check.Commentf("expected %q: %s", busyboxRe.String(), out))
}
func (s *DockerRegistrySuite) TestInspectImageWithDigests(c *check.C) {
digest, err := setupImage(c)
c.Assert(err, check.IsNil, check.Commentf("error setting up image"))
imageReference := fmt.Sprintf("%s@%s", repoName, digest)
// pull from the registry using the <name>@<digest> reference
dockerCmd(c, "pull", imageReference)
out, _ := dockerCmd(c, "inspect", imageReference)
var imageJSON []types.ImageInspect
err = json.Unmarshal([]byte(out), &imageJSON)
c.Assert(err, checker.IsNil)
c.Assert(imageJSON, checker.HasLen, 1)
c.Assert(imageJSON[0].RepoDigests, checker.HasLen, 1)
c.Assert(stringutils.InSlice(imageJSON[0].RepoDigests, imageReference), checker.Equals, true)
}
func (s *DockerRegistrySuite) TestPsListContainersFilterAncestorImageByDigest(c *check.C) {
digest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
imageReference := fmt.Sprintf("%s@%s", repoName, digest)
// pull from the registry using the <name>@<digest> reference
dockerCmd(c, "pull", imageReference)
// build a image from it
imageName1 := "images_ps_filter_test"
_, err = buildImage(imageName1, fmt.Sprintf(
`FROM %s
LABEL match me 1`, imageReference), true)
c.Assert(err, checker.IsNil)
// run a container based on that
out, _ := dockerCmd(c, "run", "-d", imageReference, "echo", "hello")
expectedID := strings.TrimSpace(out)
// run a container based on the a descendant of that too
out, _ = dockerCmd(c, "run", "-d", imageName1, "echo", "hello")
expectedID1 := strings.TrimSpace(out)
expectedIDs := []string{expectedID, expectedID1}
// Invalid imageReference
out, _ = dockerCmd(c, "ps", "-a", "-q", "--no-trunc", fmt.Sprintf("--filter=ancestor=busybox@%s", digest))
// Filter container for ancestor filter should be empty
c.Assert(strings.TrimSpace(out), checker.Equals, "")
// Valid imageReference
out, _ = dockerCmd(c, "ps", "-a", "-q", "--no-trunc", "--filter=ancestor="+imageReference)
checkPsAncestorFilterOutput(c, out, imageReference, expectedIDs)
}
func (s *DockerRegistrySuite) TestDeleteImageByIDOnlyPulledByDigest(c *check.C) {
pushDigest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
// pull from the registry using the <name>@<digest> reference
imageReference := fmt.Sprintf("%s@%s", repoName, pushDigest)
dockerCmd(c, "pull", imageReference)
// just in case...
imageID := inspectField(c, imageReference, "Id")
dockerCmd(c, "rmi", imageID)
}
func (s *DockerRegistrySuite) TestDeleteImageWithDigestAndTag(c *check.C) {
pushDigest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
// pull from the registry using the <name>@<digest> reference
imageReference := fmt.Sprintf("%s@%s", repoName, pushDigest)
dockerCmd(c, "pull", imageReference)
imageID := inspectField(c, imageReference, "Id")
repoTag := repoName + ":sometag"
repoTag2 := repoName + ":othertag"
dockerCmd(c, "tag", imageReference, repoTag)
dockerCmd(c, "tag", imageReference, repoTag2)
dockerCmd(c, "rmi", repoTag2)
// rmi should have deleted only repoTag2, because there's another tag
inspectField(c, repoTag, "Id")
dockerCmd(c, "rmi", repoTag)
// rmi should have deleted the tag, the digest reference, and the image itself
_, err = inspectFieldWithError(imageID, "Id")
c.Assert(err, checker.NotNil, check.Commentf("image should have been deleted"))
}
// TestPullFailsWithAlteredManifest tests that a `docker pull` fails when
// we have modified a manifest blob and its digest cannot be verified.
// This is the schema2 version of the test.
func (s *DockerRegistrySuite) TestPullFailsWithAlteredManifest(c *check.C) {
testRequires(c, DaemonIsLinux)
manifestDigest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
// Load the target manifest blob.
manifestBlob := s.reg.readBlobContents(c, manifestDigest)
var imgManifest schema2.Manifest
err = json.Unmarshal(manifestBlob, &imgManifest)
c.Assert(err, checker.IsNil, check.Commentf("unable to decode image manifest from blob"))
// Change a layer in the manifest.
imgManifest.Layers[0].Digest = digest.Digest("sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef")
// Move the existing data file aside, so that we can replace it with a
// malicious blob of data. NOTE: we defer the returned undo func.
undo := s.reg.tempMoveBlobData(c, manifestDigest)
defer undo()
alteredManifestBlob, err := json.MarshalIndent(imgManifest, "", " ")
c.Assert(err, checker.IsNil, check.Commentf("unable to encode altered image manifest to JSON"))
s.reg.writeBlobContents(c, manifestDigest, alteredManifestBlob)
// Now try pulling that image by digest. We should get an error about
// digest verification for the manifest digest.
// Pull from the registry using the <name>@<digest> reference.
imageReference := fmt.Sprintf("%s@%s", repoName, manifestDigest)
out, exitStatus, _ := dockerCmdWithError("pull", imageReference)
c.Assert(exitStatus, checker.Not(check.Equals), 0)
expectedErrorMsg := fmt.Sprintf("manifest verification failed for digest %s", manifestDigest)
c.Assert(out, checker.Contains, expectedErrorMsg)
}
// TestPullFailsWithAlteredManifest tests that a `docker pull` fails when
// we have modified a manifest blob and its digest cannot be verified.
// This is the schema1 version of the test.
func (s *DockerSchema1RegistrySuite) TestPullFailsWithAlteredManifest(c *check.C) {
testRequires(c, DaemonIsLinux)
manifestDigest, err := setupImage(c)
c.Assert(err, checker.IsNil, check.Commentf("error setting up image"))
// Load the target manifest blob.
manifestBlob := s.reg.readBlobContents(c, manifestDigest)
var imgManifest schema1.Manifest
err = json.Unmarshal(manifestBlob, &imgManifest)
c.Assert(err, checker.IsNil, check.Commentf("unable to decode image manifest from blob"))
// Change a layer in the manifest.
imgManifest.FSLayers[0] = schema1.FSLayer{
BlobSum: digest.Digest("sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef"),
}
// Move the existing data file aside, so that we can replace it with a
// malicious blob of data. NOTE: we defer the returned undo func.
undo := s.reg.tempMoveBlobData(c, manifestDigest)
defer undo()
alteredManifestBlob, err := json.MarshalIndent(imgManifest, "", " ")
c.Assert(err, checker.IsNil, check.Commentf("unable to encode altered image manifest to JSON"))
s.reg.writeBlobContents(c, manifestDigest, alteredManifestBlob)
// Now try pulling that image by digest. We should get an error about
// digest verification for the manifest digest.
// Pull from the registry using the <name>@<digest> reference.
imageReference := fmt.Sprintf("%s@%s", repoName, manifestDigest)
out, exitStatus, _ := dockerCmdWithError("pull", imageReference)
c.Assert(exitStatus, checker.Not(check.Equals), 0)
expectedErrorMsg := fmt.Sprintf("image verification failed for digest %s", manifestDigest)
c.Assert(out, checker.Contains, expectedErrorMsg)
}
// TestPullFailsWithAlteredLayer tests that a `docker pull` fails when
// we have modified a layer blob and its digest cannot be verified.
// This is the schema2 version of the test.
func (s *DockerRegistrySuite) TestPullFailsWithAlteredLayer(c *check.C) {
testRequires(c, DaemonIsLinux)
manifestDigest, err := setupImage(c)
c.Assert(err, checker.IsNil)
// Load the target manifest blob.
manifestBlob := s.reg.readBlobContents(c, manifestDigest)
var imgManifest schema2.Manifest
err = json.Unmarshal(manifestBlob, &imgManifest)
c.Assert(err, checker.IsNil)
// Next, get the digest of one of the layers from the manifest.
targetLayerDigest := imgManifest.Layers[0].Digest
// Move the existing data file aside, so that we can replace it with a
// malicious blob of data. NOTE: we defer the returned undo func.
undo := s.reg.tempMoveBlobData(c, targetLayerDigest)
defer undo()
// Now make a fake data blob in this directory.
s.reg.writeBlobContents(c, targetLayerDigest, []byte("This is not the data you are looking for."))
// Now try pulling that image by digest. We should get an error about
// digest verification for the target layer digest.
// Remove distribution cache to force a re-pull of the blobs
if err := os.RemoveAll(filepath.Join(dockerBasePath, "image", s.d.storageDriver, "distribution")); err != nil {
c.Fatalf("error clearing distribution cache: %v", err)
}
// Pull from the registry using the <name>@<digest> reference.
imageReference := fmt.Sprintf("%s@%s", repoName, manifestDigest)
out, exitStatus, _ := dockerCmdWithError("pull", imageReference)
c.Assert(exitStatus, checker.Not(check.Equals), 0, check.Commentf("expected a zero exit status"))
expectedErrorMsg := fmt.Sprintf("filesystem layer verification failed for digest %s", targetLayerDigest)
c.Assert(out, checker.Contains, expectedErrorMsg, check.Commentf("expected error message in output: %s", out))
}
// TestPullFailsWithAlteredLayer tests that a `docker pull` fails when
// we have modified a layer blob and its digest cannot be verified.
// This is the schema1 version of the test.
func (s *DockerSchema1RegistrySuite) TestPullFailsWithAlteredLayer(c *check.C) {
testRequires(c, DaemonIsLinux)
manifestDigest, err := setupImage(c)
c.Assert(err, checker.IsNil)
// Load the target manifest blob.
manifestBlob := s.reg.readBlobContents(c, manifestDigest)
var imgManifest schema1.Manifest
err = json.Unmarshal(manifestBlob, &imgManifest)
c.Assert(err, checker.IsNil)
// Next, get the digest of one of the layers from the manifest.
targetLayerDigest := imgManifest.FSLayers[0].BlobSum
// Move the existing data file aside, so that we can replace it with a
// malicious blob of data. NOTE: we defer the returned undo func.
undo := s.reg.tempMoveBlobData(c, targetLayerDigest)
defer undo()
// Now make a fake data blob in this directory.
s.reg.writeBlobContents(c, targetLayerDigest, []byte("This is not the data you are looking for."))
// Now try pulling that image by digest. We should get an error about
// digest verification for the target layer digest.
// Remove distribution cache to force a re-pull of the blobs
if err := os.RemoveAll(filepath.Join(dockerBasePath, "image", s.d.storageDriver, "distribution")); err != nil {
c.Fatalf("error clearing distribution cache: %v", err)
}
// Pull from the registry using the <name>@<digest> reference.
imageReference := fmt.Sprintf("%s@%s", repoName, manifestDigest)
out, exitStatus, _ := dockerCmdWithError("pull", imageReference)
c.Assert(exitStatus, checker.Not(check.Equals), 0, check.Commentf("expected a zero exit status"))
expectedErrorMsg := fmt.Sprintf("filesystem layer verification failed for digest %s", targetLayerDigest)
c.Assert(out, checker.Contains, expectedErrorMsg, check.Commentf("expected error message in output: %s", out))
}