test(e2e): add specs to hint for pulling unnamed layers

test/e2e/README.md

@@ -189,6 +189,9 @@ graph TD;
         G1["referrer.index(image)"] -- subject --> F1
         G2["referrer.image(image)"] -- subject --> F2
         G3["index"] -- subject --> F1
+
+        H0>tag: unnamed]-..->H1["artifact contains unnamed layer"]
+        I0>tag: empty]-..->I1["artifact contains only one empty layer"]
     end
 ```
 

test/e2e/internal/testdata/artifact/empty/const.go

@@ -0,0 +1,22 @@
+/*
+Copyright The ORAS Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package empty
+
+const (
+	Tag          = "empty"
+	Digest       = "sha256:7156dd4030da2375969c4da97e051d907f54ff8e9d28cc82c57289bbd22e3f9f"
+	ArtifactType = "test/empty.artifact"
+)

test/e2e/internal/testdata/artifact/unnamed/const.go

@@ -0,0 +1,22 @@
+/*
+Copyright The ORAS Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package unnamed
+
+const (
+	Tag          = "unnamed"
+	Digest       = "sha256:977c6cf8e8aeaa35a5b5d6127e5008775d66d65985ac77634f79e1d7501bba83"
+	ArtifactType = "application/vnd.unknown.config.v1+json"
+)

test/e2e/suite/command/pull.go

@@ -27,6 +27,8 @@ import (
 	"github.com/onsi/gomega/gbytes"
 	"oras.land/oras/test/e2e/internal/testdata/artifact/blob"
 	"oras.land/oras/test/e2e/internal/testdata/artifact/config"
+	"oras.land/oras/test/e2e/internal/testdata/artifact/empty"
+	"oras.land/oras/test/e2e/internal/testdata/artifact/unnamed"
 	"oras.land/oras/test/e2e/internal/testdata/feature"
 	"oras.land/oras/test/e2e/internal/testdata/foobar"
 	"oras.land/oras/test/e2e/internal/testdata/multi_arch"
@@ -39,6 +41,31 @@ var _ = Describe("ORAS beginners:", func() {
 			out := ORAS("pull", "--help").MatchKeyWords(ExampleDesc).Exec().Out
 			gomega.Expect(out).Should(gbytes.Say("--include-subject\\s+%s", regexp.QuoteMeta(feature.Preview.Mark)))
 		})
+
+		hintMsg := func(reference string) string {
+			return fmt.Sprintf("Skipped pulling layers without file name in \"org.opencontainers.image.title\"\nUse 'oras copy %s --to-oci-layout <layout-dir>' to pull all layers.\n", reference)
+		}
+		It("should show hint for unnamed layer", func() {
+			tempDir := PrepareTempFiles()
+			ref := RegistryRef(ZOTHost, ArtifactRepo, unnamed.Tag)
+			ORAS("pull", ref).
+				WithWorkDir(tempDir).
+				MatchContent(hintMsg(ref)).Exec()
+		})
+
+		It("should not show hint for unnamed config blob", func() {
+			tempDir := PrepareTempFiles()
+			ref := RegistryRef(ZOTHost, ImageRepo, foobar.Tag)
+			out := ORAS("pull", ref).WithWorkDir(tempDir).Exec().Out
+			gomega.Expect(out).ShouldNot(gbytes.Say(hintMsg(ref)))
+		})
+
+		It("should not show hint for empty layer", func() {
+			tempDir := PrepareTempFiles()
+			ref := RegistryRef(ZOTHost, ArtifactRepo, empty.Tag)
+			out := ORAS("pull", ref).WithWorkDir(tempDir).Exec().Out
+			gomega.Expect(out).ShouldNot(gbytes.Say(hintMsg(ref)))
+		})
 	})
 })
 

test/e2e/testdata/zot/command/artifacts/blobs/sha256/7156dd4030da2375969c4da97e051d907f54ff8e9d28cc82c57289bbd22e3f9f

@@ -0,0 +1 @@
+{"schemaVersion":2,"mediaType":"application/vnd.oci.image.manifest.v1+json","artifactType":"test/empty.artifact","config":{"mediaType":"application/vnd.oci.empty.v1+json","digest":"sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a","size":2,"data":"e30="},"layers":[{"mediaType":"application/vnd.oci.empty.v1+json","digest":"sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a","size":2,"data":"e30="}],"annotations":{"org.opencontainers.image.created":"2023-11-06T08:07:54Z"}}

test/e2e/testdata/zot/command/artifacts/blobs/sha256/977c6cf8e8aeaa35a5b5d6127e5008775d66d65985ac77634f79e1d7501bba83

@@ -0,0 +1 @@
+{"schemaVersion":2,"mediaType":"application/vnd.oci.image.manifest.v1+json","config":{"mediaType":"application/vnd.unknown.config.v1+json","digest":"sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a","size":2},"layers":[{"mediaType":"application/vnd.oci.image.layer.v1.tar","digest":"sha256:2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae","size":3}]}

test/e2e/testdata/zot/command/artifacts/index.json

@@ -77,6 +77,22 @@
 			"mediaType": "application/vnd.oci.image.index.v1+json",
 			"digest": "sha256:7679bc22c33b87aa345c6950a993db98a6df7a6cc77a35c388908a3a50be6bad",
 			"size": 867
+		},
+		{
+			"mediaType": "application/vnd.oci.image.manifest.v1+json",
+			"digest": "sha256:7156dd4030da2375969c4da97e051d907f54ff8e9d28cc82c57289bbd22e3f9f",
+			"size": 519,
+			"annotations": {
+				"org.opencontainers.image.ref.name": "empty"
+			}
+		},
+		{
+			"mediaType": "application/vnd.oci.image.manifest.v1+json",
+			"digest": "sha256:977c6cf8e8aeaa35a5b5d6127e5008775d66d65985ac77634f79e1d7501bba83",
+			"size": 390,
+			"annotations": {
+				"org.opencontainers.image.ref.name": "unnamed"
+			}
 		}
 	]
 }