libimage: add more image tests

Add unit tests for exercising all kinds of function of an `Image`
object.

Also remove an unused, redundant (and incomplete) `MountPoint` function.
`Mountpoint` is used by Podman instead.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

common/libimage/image.go

@@ -658,25 +658,6 @@ func (i *Image) Unmount(force bool) error {
 	return err
 }
 
-// MountPoint returns the fully-evaluated mount point of the image.  If the
-// image isn't mounted, an empty string is returned.
-func (i *Image) MountPoint() (string, error) {
-	counter, err := i.runtime.store.Mounted(i.TopLayer())
-	if err != nil {
-		return "", err
-	}
-
-	if counter == 0 {
-		return "", nil
-	}
-
-	layer, err := i.runtime.store.Layer(i.TopLayer())
-	if err != nil {
-		return "", err
-	}
-	return filepath.EvalSymlinks(layer.MountPoint)
-}
-
 // Size computes the size of the image layers and associated data.
 func (i *Image) Size() (int64, error) {
 	return i.runtime.store.ImageSize(i.ID())

common/libimage/image_test.go

@@ -0,0 +1,164 @@
+package libimage
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/containers/common/pkg/config"
+	"github.com/containers/image/v5/transports/alltransports"
+	"github.com/pkg/errors"
+	"github.com/stretchr/testify/require"
+)
+
+func TestImageFunctions(t *testing.T) {
+	// Note: this will resolve pull from the GCR registry (see
+	// testdata/registries.conf).
+	busyboxLatest := "docker.io/library/busybox:latest"
+	busyboxDigest := "docker.io/library/busybox@"
+
+	runtime, cleanup := testNewRuntime(t)
+	defer cleanup()
+	ctx := context.Background()
+
+	// Pull busybox:latest, get its digest and then perform a digest pull.
+	// It's effectively pulling the same image twice but we need the digest
+	// for some of the tests below.
+	pullOptions := &PullOptions{}
+	pullOptions.Writer = os.Stdout
+	pulledImages, err := runtime.Pull(ctx, busyboxLatest, config.PullPolicyAlways, pullOptions)
+	require.NoError(t, err)
+	require.Len(t, pulledImages, 1)
+
+	origDigest := pulledImages[0].Digest()
+	busyboxDigest += origDigest.String()
+
+	pulledImages, err = runtime.Pull(ctx, busyboxDigest, config.PullPolicyAlways, pullOptions)
+	require.NoError(t, err)
+	require.Len(t, pulledImages, 1)
+
+	image := pulledImages[0]
+
+	// Note that the tests below are primarily meant to be smoke tests to
+	// catch broad regressions early on.
+	require.NoError(t, image.reload())
+
+	// The names history is stored in reverse order in c/storage.
+	require.Equal(t, []string{busyboxDigest, busyboxLatest}, image.Names(), "names do not match")
+	require.Equal(t, []string{busyboxLatest, busyboxDigest}, image.NamesHistory(), "names history does not match")
+
+	require.NotNil(t, image.StorageImage())
+
+	// Just make sure that the ID has 64 characters.
+	require.True(t, len(image.ID()) == 64, "ID should be 64 characters long")
+
+	// Make sure that the image we pulled by digest is the same one we
+	// pulled by tag.
+	require.Equal(t, origDigest.String(), image.Digest().String(), "digests of pulled images should match")
+
+	// NOTE: we're recording two digests. One for the image and one for the
+	// manifest list we chose it from.
+	digests := image.Digests()
+	require.Len(t, digests, 2)
+	require.Equal(t, origDigest.String(), digests[0].String(), "first recoreded digest should be the one of the image")
+
+	// Below mostly smoke tests.
+	require.False(t, image.IsReadOnly())
+	require.False(t, image.IsDangling())
+
+	isIntermediate, err := image.IsIntermediate(ctx)
+	require.NoError(t, err)
+	require.False(t, isIntermediate)
+
+	labels, err := image.Labels(ctx)
+	require.NoError(t, err)
+
+	require.True(t, image.TopLayer() != "", "non-empty top layer expected")
+
+	parent, err := image.Parent(ctx)
+	require.NoError(t, err)
+	require.Nil(t, parent)
+
+	hasChildren, err := image.HasChildren(ctx)
+	require.NoError(t, err)
+	require.False(t, hasChildren)
+
+	children, err := image.Children(ctx)
+	require.NoError(t, err)
+	require.Nil(t, children)
+
+	containers, err := image.Containers()
+	require.NoError(t, err)
+	require.Nil(t, containers)
+
+	// Since we have no containers here, we can only smoke test.
+	require.NoError(t, image.removeContainers(nil))
+	require.Error(t, image.removeContainers(func(_ string) error {
+		return errors.New("TEST")
+	}))
+
+	// Two items since both names are "Named".
+	namedRepoTags, err := image.NamedRepoTags()
+	require.NoError(t, err)
+	require.Len(t, namedRepoTags, 2)
+	require.Equal(t, busyboxLatest, namedRepoTags[1].String(), "unexpected named repo tag")
+	require.Equal(t, busyboxDigest, namedRepoTags[0].String(), "unexpected named repo tag")
+
+	// One item since only one name is "Tagged".
+	namedTaggedRepoTags, err := image.NamedTaggedRepoTags()
+	require.NoError(t, err)
+	require.Len(t, namedTaggedRepoTags, 1, "unexpected named tagged repo tag")
+	require.Equal(t, busyboxLatest, namedTaggedRepoTags[0].String(), "unexpected named tagged repo tag")
+	repoTags, err := image.RepoTags()
+	require.NoError(t, err)
+	require.Len(t, repoTags, 1, "unexpected named tagged repo tag")
+	require.Equal(t, busyboxLatest, repoTags[0], "unexpected named tagged repo tag")
+
+	repoDigests, err := image.RepoDigests()
+	require.NoError(t, err)
+	require.Len(t, repoDigests, 2, "unexpected repo digests")
+
+	mountPoint, err := image.Mount(ctx, nil, "")
+	require.NoError(t, err)
+	require.True(t, mountPoint != "", "non-empty mount point expected")
+
+	sameMountPoint, err := image.Mountpoint()
+	require.NoError(t, err)
+	require.Equal(t, mountPoint, sameMountPoint, "mount points shoud be equal")
+
+	require.NoError(t, image.Unmount(false))
+	require.NoError(t, image.Unmount(true))
+
+	// Same image -> same digest
+	remoteRef, err := alltransports.ParseImageName("docker://" + busyboxDigest)
+	require.NoError(t, err)
+	hasDifferentDigest, err := image.HasDifferentDigest(ctx, remoteRef)
+	require.NoError(t, err)
+	require.False(t, hasDifferentDigest, "image with same digest should have the same manifest (and hence digest)")
+
+	// Different images -> different digests
+	remoteRef, err = alltransports.ParseImageName("docker://docker.io/library/alpine:latest")
+	require.NoError(t, err)
+	hasDifferentDigest, err = image.HasDifferentDigest(ctx, remoteRef)
+	require.NoError(t, err)
+	require.True(t, hasDifferentDigest, "another image should have a different digest")
+
+	rawManifest, _, err := image.Manifest(ctx)
+	require.NoError(t, err)
+	require.True(t, len(rawManifest) > 0)
+
+	size, err := image.Size()
+	require.NoError(t, err)
+	require.True(t, size > 0)
+
+	// Now compare the inspect data to what we expect.
+	imageData, err := image.Inspect(ctx, true)
+	require.NoError(t, err)
+	require.Equal(t, image.ID(), imageData.ID, "inspect data should match")
+	require.Equal(t, repoTags, imageData.RepoTags, "inspect data should match")
+	require.Len(t, imageData.RepoDigests, 2, "inspect data should match")
+	require.Equal(t, size, imageData.Size, "inspect data should match")
+	require.Equal(t, image.Digest().String(), imageData.Digest.String(), "inspect data should match")
+	require.Equal(t, labels, imageData.Labels, "inspect data should match")
+	require.Equal(t, image.NamesHistory(), imageData.NamesHistory, "inspect data should match")
+}

common/libimage/testdata/registries.conf

@@ -5,5 +5,5 @@ unqualified-search-registries=["docker.io", "quay.io"]
 # limits while testing, always use the google mirror for qualified and
 # unqualified `docker.io` images.
 # Ref: https://cloud.google.com/container-registry/docs/pulling-cached-images
-#prefix="docker.io"
-#location="mirror.gcr.io"
+prefix="docker.io"
+location="mirror.gcr.io"