Merge branch '2.7.x' into 3.0.x

Closes gh-34495

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/Builder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 package org.springframework.boot.buildpack.platform.build;
 
 import java.io.IOException;
+import java.nio.file.Path;
 import java.util.List;
 import java.util.function.Consumer;
 
@@ -32,7 +33,6 @@ import org.springframework.boot.buildpack.platform.docker.transport.DockerEngine
 import org.springframework.boot.buildpack.platform.docker.type.Image;
 import org.springframework.boot.buildpack.platform.docker.type.ImageReference;
 import org.springframework.boot.buildpack.platform.io.IOBiConsumer;
-import org.springframework.boot.buildpack.platform.io.TarArchive;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
@@ -273,9 +273,8 @@ public class Builder {
 		}
 
 		@Override
-		public void exportImageLayers(ImageReference reference, IOBiConsumer<String, TarArchive> exports)
+		public void exportImageLayers(ImageReference reference, IOBiConsumer<String, Path> exports) throws IOException {
-				throws IOException {
+			Builder.this.docker.image().exportLayerFiles(reference, exports);
-			Builder.this.docker.image().exportLayers(reference, exports);
 		}
 
 	}

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/BuildpackResolverContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,12 +17,12 @@
 package org.springframework.boot.buildpack.platform.build;
 
 import java.io.IOException;
+import java.nio.file.Path;
 import java.util.List;
 
 import org.springframework.boot.buildpack.platform.docker.type.Image;
 import org.springframework.boot.buildpack.platform.docker.type.ImageReference;
 import org.springframework.boot.buildpack.platform.io.IOBiConsumer;
-import org.springframework.boot.buildpack.platform.io.TarArchive;
 
 /**
  * Context passed to a {@link BuildpackResolver}.
@@ -52,6 +52,6 @@ interface BuildpackResolverContext {
 	 * during the callback)
 	 * @throws IOException on IO error
 	 */
-	void exportImageLayers(ImageReference reference, IOBiConsumer<String, TarArchive> exports) throws IOException;
+	void exportImageLayers(ImageReference reference, IOBiConsumer<String, Path> exports) throws IOException;
 
 }

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/build/ImageBuildpack.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.buildpack.platform.build;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -35,7 +36,6 @@ import org.springframework.boot.buildpack.platform.docker.type.ImageReference;
 import org.springframework.boot.buildpack.platform.docker.type.Layer;
 import org.springframework.boot.buildpack.platform.docker.type.LayerId;
 import org.springframework.boot.buildpack.platform.io.IOConsumer;
-import org.springframework.boot.buildpack.platform.io.TarArchive;
 import org.springframework.util.StreamUtils;
 
 /**
@@ -115,23 +115,16 @@ final class ImageBuildpack implements Buildpack {
 
 		ExportedLayers(BuildpackResolverContext context, ImageReference imageReference) throws IOException {
 			List<Path> layerFiles = new ArrayList<>();
-			context.exportImageLayers(imageReference, (name, archive) -> layerFiles.add(copyToTemp(name, archive)));
+			context.exportImageLayers(imageReference, (name, path) -> layerFiles.add(copyToTemp(path)));
 			this.layerFiles = Collections.unmodifiableList(layerFiles);
 		}
 
-		private Path copyToTemp(String name, TarArchive archive) throws IOException {
+		private Path copyToTemp(Path path) throws IOException {
-			String[] parts = name.split("/");
+			Path outputPath = Files.createTempFile("create-builder-scratch-", null);
-			Path path = Files.createTempFile("create-builder-scratch-", parts[0]);
+			try (OutputStream out = Files.newOutputStream(outputPath)) {
-			try (OutputStream out = Files.newOutputStream(path)) {
+				copyLayerTar(path, out);
-				archive.writeTo(out);
-			}
-			return path;
-		}
-
-		void apply(IOConsumer<Layer> layers) throws IOException {
-			for (Path path : this.layerFiles) {
-				layers.accept(Layer.fromTarArchive((out) -> copyLayerTar(path, out)));
 			}
+			return outputPath;
 		}
 
 		private void copyLayerTar(Path path, OutputStream out) throws IOException {
@@ -147,7 +140,16 @@ final class ImageBuildpack implements Buildpack {
 				}
 				tarOut.finish();
 			}
-			Files.delete(path);
+		}
+
+		void apply(IOConsumer<Layer> layers) throws IOException {
+			for (Path path : this.layerFiles) {
+				layers.accept(Layer.fromTarArchive((out) -> {
+					InputStream in = Files.newInputStream(path);
+					StreamUtils.copy(in, out);
+				}));
+				Files.delete(path);
+			}
 		}
 
 	}

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/DockerApi.java

@@ -16,13 +16,24 @@
 
 package org.springframework.boot.buildpack.platform.docker;
 
+import java.io.BufferedReader;
+import java.io.ByteArrayInputStream;
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
 
 import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
 import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
@@ -37,6 +48,7 @@ import org.springframework.boot.buildpack.platform.docker.type.ContainerReferenc
 import org.springframework.boot.buildpack.platform.docker.type.ContainerStatus;
 import org.springframework.boot.buildpack.platform.docker.type.Image;
 import org.springframework.boot.buildpack.platform.docker.type.ImageArchive;
+import org.springframework.boot.buildpack.platform.docker.type.ImageArchiveManifest;
 import org.springframework.boot.buildpack.platform.docker.type.ImageReference;
 import org.springframework.boot.buildpack.platform.docker.type.VolumeName;
 import org.springframework.boot.buildpack.platform.io.IOBiConsumer;
@@ -250,7 +262,7 @@ public class DockerApi {
 		}
 
 		/**
-		 * Export the layers of an image.
+		 * Export the layers of an image as {@link TarArchive}s.
 		 * @param reference the reference to export
 		 * @param exports a consumer to receive the layers (contents can only be accessed
 		 * during the callback)
@@ -258,20 +270,49 @@ public class DockerApi {
 		 */
 		public void exportLayers(ImageReference reference, IOBiConsumer<String, TarArchive> exports)
 				throws IOException {
+			exportLayerFiles(reference, (name, path) -> {
+				try (InputStream in = Files.newInputStream(path)) {
+					TarArchive archive = (out) -> StreamUtils.copy(in, out);
+					exports.accept(name, archive);
+				}
+			});
+		}
+
+		/**
+		 * Export the layers of an image as paths to layer tar files.
+		 * @param reference the reference to export
+		 * @param exports a consumer to receive the layer tar file paths (file can only be
+		 * accessed during the callback)
+		 * @throws IOException on IO error
+		 */
+		public void exportLayerFiles(ImageReference reference, IOBiConsumer<String, Path> exports) throws IOException {
 			Assert.notNull(reference, "Reference must not be null");
 			Assert.notNull(exports, "Exports must not be null");
 			URI saveUri = buildUrl("/images/" + reference + "/get");
 			Response response = http().get(saveUri);
+			ImageArchiveManifest manifest = null;
+			Map<String, Path> layerFiles = new HashMap<>();
 			try (TarArchiveInputStream tar = new TarArchiveInputStream(response.getContent())) {
 				TarArchiveEntry entry = tar.getNextTarEntry();
 				while (entry != null) {
-					if (entry.getName().endsWith("/layer.tar")) {
+					if (entry.getName().equals("manifest.json")) {
-						TarArchive archive = (out) -> StreamUtils.copy(tar, out);
+						manifest = readManifest(tar);
-						exports.accept(entry.getName(), archive);
+					}
+					if (entry.getName().endsWith(".tar")) {
+						layerFiles.put(entry.getName(), copyToTemp(tar));
 					}
 					entry = tar.getNextTarEntry();
 				}
 			}
+			Assert.notNull(manifest, "Manifest not found in image " + reference);
+			for (Map.Entry<String, Path> entry : layerFiles.entrySet()) {
+				String name = entry.getKey();
+				Path path = entry.getValue();
+				if (manifestContainsLayerEntry(manifest, name)) {
+					exports.accept(name, path);
+				}
+				Files.delete(path);
+			}
 		}
 
 		/**
@@ -308,6 +349,24 @@ public class DockerApi {
 			http().post(uri).close();
 		}
 
+		private ImageArchiveManifest readManifest(TarArchiveInputStream tar) throws IOException {
+			String manifestContent = new BufferedReader(new InputStreamReader(tar, StandardCharsets.UTF_8)).lines()
+				.collect(Collectors.joining());
+			return ImageArchiveManifest.of(new ByteArrayInputStream(manifestContent.getBytes(StandardCharsets.UTF_8)));
+		}
+
+		private Path copyToTemp(TarArchiveInputStream in) throws IOException {
+			Path path = Files.createTempFile("create-builder-scratch-", null);
+			try (OutputStream out = Files.newOutputStream(path)) {
+				StreamUtils.copy(in, out);
+			}
+			return path;
+		}
+
+		private boolean manifestContainsLayerEntry(ImageArchiveManifest manifest, String layerId) {
+			return manifest.getEntries().stream().anyMatch((content) -> content.getLayers().contains(layerId));
+		}
+
 	}
 
 	/**

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/type/ImageArchiveManifest.java

@@ -0,0 +1,95 @@
+/*
+ * Copyright 2012-2023 the original author or 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
+ *
+ *      https://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 org.springframework.boot.buildpack.platform.docker.type;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.lang.invoke.MethodHandles;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import com.fasterxml.jackson.databind.JsonNode;
+
+import org.springframework.boot.buildpack.platform.json.MappedObject;
+
+/**
+ * Image archive manifest information.
+ *
+ * @author Scott Frederick
+ * @since 2.7.9
+ */
+public class ImageArchiveManifest extends MappedObject {
+
+	private final List<ManifestEntry> entries = new ArrayList<>();
+
+	protected ImageArchiveManifest(JsonNode node) {
+		super(node, MethodHandles.lookup());
+		getNode().elements().forEachRemaining((element) -> this.entries.add(ManifestEntry.of(element)));
+	}
+
+	/**
+	 * Return the entries contained in the manifest.
+	 * @return the manifest entries
+	 */
+	public List<ManifestEntry> getEntries() {
+		return this.entries;
+	}
+
+	/**
+	 * Create an {@link ImageArchiveManifest} from the provided JSON input stream.
+	 * @param content the JSON input stream
+	 * @return a new {@link ImageArchiveManifest} instance
+	 * @throws IOException on IO error
+	 */
+	public static ImageArchiveManifest of(InputStream content) throws IOException {
+		return of(content, ImageArchiveManifest::new);
+	}
+
+	public static class ManifestEntry extends MappedObject {
+
+		private final List<String> layers;
+
+		protected ManifestEntry(JsonNode node) {
+			super(node, MethodHandles.lookup());
+			this.layers = extractLayers();
+		}
+
+		/**
+		 * Return the collection of layer IDs from a section of the manifest.
+		 * @return a collection of layer IDs
+		 */
+		public List<String> getLayers() {
+			return this.layers;
+		}
+
+		static ManifestEntry of(JsonNode node) {
+			return new ManifestEntry(node);
+		}
+
+		@SuppressWarnings("unchecked")
+		private List<String> extractLayers() {
+			List<String> layers = valueAt("/Layers", List.class);
+			if (layers == null) {
+				return Collections.emptyList();
+			}
+			return layers;
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/build/ImageBuildpackTests.java

@@ -18,7 +18,10 @@ package org.springframework.boot.buildpack.platform.build;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.FileOutputStream;
 import java.io.IOException;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Random;
@@ -33,7 +36,6 @@ import org.mockito.invocation.InvocationOnMock;
 import org.springframework.boot.buildpack.platform.docker.type.Image;
 import org.springframework.boot.buildpack.platform.docker.type.ImageReference;
 import org.springframework.boot.buildpack.platform.io.IOBiConsumer;
-import org.springframework.boot.buildpack.platform.io.TarArchive;
 import org.springframework.boot.buildpack.platform.json.AbstractJsonTests;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -173,20 +175,20 @@ class ImageBuildpackTests extends AbstractJsonTests {
 
 	private Object withMockLayers(InvocationOnMock invocation) {
 		try {
-			IOBiConsumer<String, TarArchive> consumer = invocation.getArgument(1);
+			IOBiConsumer<String, Path> consumer = invocation.getArgument(1);
-			TarArchive archive = (out) -> {
+			File tarFile = File.createTempFile("create-builder-test-", null);
-				try (TarArchiveOutputStream tarOut = new TarArchiveOutputStream(out)) {
+			FileOutputStream out = new FileOutputStream(tarFile);
-					tarOut.setLongFileMode(TarArchiveOutputStream.LONGFILE_POSIX);
+			try (TarArchiveOutputStream tarOut = new TarArchiveOutputStream(out)) {
-					writeTarEntry(tarOut, "/cnb/");
+				tarOut.setLongFileMode(TarArchiveOutputStream.LONGFILE_POSIX);
-					writeTarEntry(tarOut, "/cnb/buildpacks/");
+				writeTarEntry(tarOut, "/cnb/");
-					writeTarEntry(tarOut, "/cnb/buildpacks/example_buildpack/");
+				writeTarEntry(tarOut, "/cnb/buildpacks/");
-					writeTarEntry(tarOut, "/cnb/buildpacks/example_buildpack/0.0.1/");
+				writeTarEntry(tarOut, "/cnb/buildpacks/example_buildpack/");
-					writeTarEntry(tarOut, "/cnb/buildpacks/example_buildpack/0.0.1/buildpack.toml");
+				writeTarEntry(tarOut, "/cnb/buildpacks/example_buildpack/0.0.1/");
-					writeTarEntry(tarOut, "/cnb/buildpacks/example_buildpack/0.0.1/" + this.longFilePath);
+				writeTarEntry(tarOut, "/cnb/buildpacks/example_buildpack/0.0.1/buildpack.toml");
-					tarOut.finish();
+				writeTarEntry(tarOut, "/cnb/buildpacks/example_buildpack/0.0.1/" + this.longFilePath);
-				}
+				tarOut.finish();
-			};
+			}
-			consumer.accept("test", archive);
+			consumer.accept("test", tarFile.toPath());
 		}
 		catch (IOException ex) {
 			fail("Error writing mock layers", ex);

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/docker/DockerApiTests.java

@@ -21,6 +21,9 @@ import java.io.ByteArrayOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URI;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
 
 import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
 import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;
@@ -310,14 +313,14 @@ class DockerApiTests {
 
 		@Test
 		void exportLayersWhenReferenceIsNullThrowsException() {
-			assertThatIllegalArgumentException().isThrownBy(() -> this.api.exportLayers(null, (name, archive) -> {
+			assertThatIllegalArgumentException().isThrownBy(() -> this.api.exportLayerFiles(null, (name, archive) -> {
 			})).withMessage("Reference must not be null");
 		}
 
 		@Test
 		void exportLayersWhenExportsIsNullThrowsException() {
 			ImageReference reference = ImageReference.of("gcr.io/paketo-buildpacks/builder:base");
-			assertThatIllegalArgumentException().isThrownBy(() -> this.api.exportLayers(reference, null))
+			assertThatIllegalArgumentException().isThrownBy(() -> this.api.exportLayerFiles(reference, null))
 				.withMessage("Exports must not be null");
 		}
 
@@ -340,11 +343,62 @@ class DockerApiTests {
 				}
 			});
 			assertThat(contents).hasSize(3)
-				.containsKeys("1bf6c63a1e9ed1dd7cb961273bf60b8e0f440361faf273baf866f408e4910601/layer.tar",
+				.containsKeys("70bb7a3115f3d5c01099852112c7e05bf593789e510468edb06b6a9a11fa3b73/layer.tar",
-						"8fdfb915302159a842cbfae6faec5311b00c071ebf14e12da7116ae7532e9319/layer.tar",
+						"74a9a50ece13c025cf10e9110d9ddc86c995079c34e2a22a28d1a3d523222c6e/layer.tar",
-						"93cd584bb189bfca4f51744bd19d836fd36da70710395af5a1523ee88f208c6a/layer.tar");
+						"a69532b5b92bb891fbd9fa1a6b3af9087ea7050255f59ba61a796f8555ecd783/layer.tar");
-			assertThat(contents.get("1bf6c63a1e9ed1dd7cb961273bf60b8e0f440361faf273baf866f408e4910601/layer.tar"))
+			assertThat(contents.get("70bb7a3115f3d5c01099852112c7e05bf593789e510468edb06b6a9a11fa3b73/layer.tar"))
-				.containsExactly("etc/", "etc/apt/", "etc/apt/sources.list");
+				.containsExactly("/cnb/order.toml");
+			assertThat(contents.get("74a9a50ece13c025cf10e9110d9ddc86c995079c34e2a22a28d1a3d523222c6e/layer.tar"))
+				.containsExactly("/cnb/stack.toml");
+		}
+
+		@Test
+		void exportLayersWithSymlinksExportsLayerTars() throws Exception {
+			ImageReference reference = ImageReference.of("gcr.io/paketo-buildpacks/builder:base");
+			URI exportUri = new URI(IMAGES_URL + "/gcr.io/paketo-buildpacks/builder:base/get");
+			given(DockerApiTests.this.http.get(exportUri)).willReturn(responseOf("export-symlinks.tar"));
+			MultiValueMap<String, String> contents = new LinkedMultiValueMap<>();
+			this.api.exportLayers(reference, (name, archive) -> {
+				ByteArrayOutputStream out = new ByteArrayOutputStream();
+				archive.writeTo(out);
+				try (TarArchiveInputStream in = new TarArchiveInputStream(
+						new ByteArrayInputStream(out.toByteArray()))) {
+					TarArchiveEntry entry = in.getNextTarEntry();
+					while (entry != null) {
+						contents.add(name, entry.getName());
+						entry = in.getNextTarEntry();
+					}
+				}
+			});
+			assertThat(contents).hasSize(3)
+				.containsKeys("6aa3691a73805f608e5fce69fb6bc89aec8362f58a6b4be2682515e9cfa3cc1a.tar",
+						"762e198f655bc2580ef3e56b538810fd2b9981bd707f8a44c70344b58f9aee68.tar",
+						"d3cc975ad97fdfbb73d9daf157e7f658d6117249fd9c237e3856ad173c87e1d2.tar");
+			assertThat(contents.get("d3cc975ad97fdfbb73d9daf157e7f658d6117249fd9c237e3856ad173c87e1d2.tar"))
+				.containsExactly("/cnb/order.toml");
+			assertThat(contents.get("762e198f655bc2580ef3e56b538810fd2b9981bd707f8a44c70344b58f9aee68.tar"))
+				.containsExactly("/cnb/stack.toml");
+		}
+
+		@Test
+		void exportLayerFilesDeletesTempFiles() throws Exception {
+			ImageReference reference = ImageReference.of("gcr.io/paketo-buildpacks/builder:base");
+			URI exportUri = new URI(IMAGES_URL + "/gcr.io/paketo-buildpacks/builder:base/get");
+			given(DockerApiTests.this.http.get(exportUri)).willReturn(responseOf("export.tar"));
+			List<Path> layerFilePaths = new ArrayList<>();
+			this.api.exportLayerFiles(reference, (name, path) -> layerFilePaths.add(path));
+			layerFilePaths.forEach((path) -> assertThat(path.toFile()).doesNotExist());
+		}
+
+		@Test
+		void exportLayersWithNoManifestThrowsException() throws Exception {
+			ImageReference reference = ImageReference.of("gcr.io/paketo-buildpacks/builder:base");
+			URI exportUri = new URI(IMAGES_URL + "/gcr.io/paketo-buildpacks/builder:base/get");
+			given(DockerApiTests.this.http.get(exportUri)).willReturn(responseOf("export-no-manifest.tar"));
+			assertThatIllegalArgumentException()
+				.isThrownBy(() -> this.api.exportLayerFiles(reference, (name, archive) -> {
+				}))
+				.withMessageContaining("Manifest not found in image " + reference);
 		}
 
 		@Test

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/docker/type/ImageArchiveManifestTests.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2012-2023 the original author or 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
+ *
+ *      https://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 org.springframework.boot.buildpack.platform.docker.type;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.buildpack.platform.json.AbstractJsonTests;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link ImageArchiveManifest}.
+ *
+ * @author Scott Frederick
+ * @author Andy Wilkinson
+ */
+class ImageArchiveManifestTests extends AbstractJsonTests {
+
+	@Test
+	void getLayersReturnsLayers() throws Exception {
+		ImageArchiveManifest manifest = getManifest();
+		List<String> expectedLayers = new ArrayList<>();
+		for (int blankLayersCount = 0; blankLayersCount < 46; blankLayersCount++) {
+			expectedLayers.add("blank_" + blankLayersCount);
+		}
+		expectedLayers.add("bb09e17fd1bd2ee47155f1349645fcd9fff31e1247c7ed99cad469f1c16a4216.tar");
+		assertThat(manifest.getEntries()).hasSize(1);
+		assertThat(manifest.getEntries().get(0).getLayers()).hasSize(47);
+		assertThat(manifest.getEntries().get(0).getLayers()).isEqualTo(expectedLayers);
+	}
+
+	@Test
+	void getLayersWithNoLayersReturnsEmptyList() throws Exception {
+		String content = "[{\"Layers\": []}]";
+		ImageArchiveManifest manifest = new ImageArchiveManifest(getObjectMapper().readTree(content));
+		assertThat(manifest.getEntries()).hasSize(1);
+		assertThat(manifest.getEntries().get(0).getLayers()).hasSize(0);
+	}
+
+	@Test
+	void getLayersWithEmptyManifestReturnsEmptyList() throws Exception {
+		String content = "[]";
+		ImageArchiveManifest manifest = new ImageArchiveManifest(getObjectMapper().readTree(content));
+		assertThat(manifest.getEntries()).isEmpty();
+	}
+
+	private ImageArchiveManifest getManifest() throws IOException {
+		return new ImageArchiveManifest(getObjectMapper().readTree(getContent("image-archive-manifest.json")));
+	}
+
+}