Add tests for configuring layered jar layout

Closes gh-19768

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/java/org/springframework/boot/maven/JarIntegrationTests.java

@@ -26,6 +26,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  * Integration tests for the Maven plugin's jar support.
  *
  * @author Andy Wilkinson
+ * @author Madhura Bhave
  */
 @ExtendWith(MavenBuildExtension.class)
 class JarIntegrationTests extends AbstractArchiveIntegrationTests {
@@ -280,4 +281,14 @@ class JarIntegrationTests extends AbstractArchiveIntegrationTests {
 		});
 	}
 
+	@TestTemplate
+	void whenJarIsRepackagedWithTheLayeredLayoutTheJarContainsLayers(MavenBuild mavenBuild) {
+		mavenBuild.project("jar-layered").execute((project) -> {
+			File repackaged = new File(project, "jar/target/jar-layered-0.0.1.BUILD-SNAPSHOT.jar");
+			assertThat(jar(repackaged)).hasEntryWithNameStartingWith("BOOT-INF/layers/application/classes/")
+					.hasEntryWithNameStartingWith("BOOT-INF/layers/dependencies/lib/jar-release")
+					.hasEntryWithNameStartingWith("BOOT-INF/layers/snapshot-dependencies/lib/jar-snapshot");
+		});
+	}
+
 }

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/jar-layered/jar-release/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-release</artifactId>
+	<version>0.0.1.RELEASE</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Release Jar dependency</description>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/jar-layered/jar-snapshot/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-snapshot</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<packaging>jar</packaging>
+	<name>jar</name>
+	<description>Snapshot Jar dependency</description>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/jar-layered/jar/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>jar-layered</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.source>@java.version@</maven.compiler.source>
+		<maven.compiler.target>@java.version@</maven.compiler.target>
+	</properties>
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>@project.groupId@</groupId>
+				<artifactId>@project.artifactId@</artifactId>
+				<version>@project.version@</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>repackage</goal>
+						</goals>
+						<configuration>
+							<layout>LAYERED_JAR</layout>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-snapshot</artifactId>
+			<version>0.0.1.BUILD-SNAPSHOT</version>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot.maven.it</groupId>
+			<artifactId>jar-release</artifactId>
+			<version>0.0.1.RELEASE</version>
+		</dependency>
+	</dependencies>
+</project>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/jar-layered/jar/src/main/java/org/test/SampleApplication.java

+/*
+ * Copyright 2012-2020 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.test;
+
+public class SampleApplication {
+
+	public static void main(String[] args) {
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/intTest/projects/jar-layered/pom.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.springframework.boot.maven.it</groupId>
+	<artifactId>aggregator</artifactId>
+	<version>0.0.1.BUILD-SNAPSHOT</version>
+	<packaging>pom</packaging>
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.source>@java.version@</maven.compiler.source>
+		<maven.compiler.target>@java.version@</maven.compiler.target>
+	</properties>
+	<modules>
+		<module>jar-snapshot</module>
+		<module>jar-release</module>
+		<module>jar</module>
+	</modules>
+</project>