integration: Adds test for multilayer image import

This test will make sure there aren't any issues with multilayered
images during import. Keep in mind that in the case of multilayered
images, they have to be unpacked first in order to be usable.

Signed-off-by: Claudiu Belu <cbelu@cloudbasesolutions.com>

integration/client/client_unix_test.go

@@ -32,9 +32,10 @@ const (
 )
 
 var (
-	testImage    = "ghcr.io/containerd/busybox:1.32"
-	shortCommand = withProcessArgs("true")
-	longCommand  = withProcessArgs("/bin/sh", "-c", "while true; do sleep 1; done")
+	testImage             = "ghcr.io/containerd/busybox:1.32"
+	testMultiLayeredImage = "gcr.io/k8s-cri-containerd/volume-copy-up:2.1"
+	shortCommand          = withProcessArgs("true")
+	longCommand           = withProcessArgs("/bin/sh", "-c", "while true; do sleep 1; done")
 )
 
 func TestImagePullSchema1WithEmptyLayers(t *testing.T) {