Add Integration Test for issue #2875

This integration test shows that `download.md5` and
`download.checksum.md5` are present after running the
`fix-artifacts-metadata` goal when they shouldn't.

If these are not removed and the content of the artifact changed then,
after the recalculation done by this goal, new p2 libs will see an
outdated value for these old checksum algorithms and will fail the
installation due to a checksum mismatch.

(cherry picked from commit b88a16e)

tycho-its/projects/p2Repository.fixArtifactsMetadata.oldChecksums/category.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<site>
+   <bundle id="org.slf4j.api" version="0.0.0"/>
+</site>

tycho-its/projects/p2Repository.fixArtifactsMetadata.oldChecksums/pom.xml

@@ -0,0 +1,54 @@
+<?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/maven-v4_0_0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+
+	<groupId>tycho-its-project.p2Repository.fixArtifactsMetadata.oldChecksums</groupId>
+	<artifactId>pfo.repository</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<packaging>eclipse-repository</packaging>
+
+	<properties>
+		<tycho-version>4.0.8</tycho-version>
+	</properties>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.eclipse.tycho</groupId>
+				<artifactId>tycho-maven-plugin</artifactId>
+				<version>${tycho-version}</version>
+				<extensions>true</extensions>
+			</plugin>
+			<plugin>
+				<groupId>org.eclipse.tycho</groupId>
+				<artifactId>target-platform-configuration</artifactId>
+				<version>${tycho-version}</version>
+				<configuration>
+					<target>
+						<file>test.target</file>
+					</target>
+				</configuration>
+			</plugin>
+			<plugin>
+				<groupId>org.eclipse.tycho</groupId>
+				<artifactId>tycho-p2-repository-plugin</artifactId>
+				<version>${tycho-version}</version>
+				<executions>
+					<execution>
+						<id>fix</id>
+						<goals>
+							<goal>fix-artifacts-metadata</goal>
+						</goals>
+					</execution>
+					<execution>
+						<id>verify</id>
+						<goals>
+							<goal>verify-repository</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+</project>

tycho-its/projects/p2Repository.fixArtifactsMetadata.oldChecksums/test.target

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<?pde version="3.8"?>
+
+<target name="p2Repository.fixArtifactsMetadata.oldChecksums.target" sequenceNumber="1">
+
+	<locations>
+		<location includeAllPlatforms="false" includeConfigurePhase="false" includeMode="slicer" includeSource="false" type="InstallableUnit">
+			<unit id="org.slf4j.api" version="0.0.0"/>
+
+			<repository location="https://download.eclipse.org/tools/orbit/downloads/drops/R20220531185310/repository/"/>
+		</location>
+	</locations>
+
+</target>

tycho-its/src/test/java/org/eclipse/tycho/test/p2Repository/P2RepositoryFixArtifactsMetadataOldChecksumsTest.java

@@ -0,0 +1,81 @@
+/*******************************************************************************
+ * Copyright (c) 2024 Martin D'Aloia and others.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *******************************************************************************/
+package org.eclipse.tycho.test.p2Repository;
+
+import static java.util.Arrays.asList;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Arrays;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import org.apache.maven.it.Verifier;
+import org.codehaus.plexus.util.xml.Xpp3Dom;
+import org.codehaus.plexus.util.xml.Xpp3DomBuilder;
+import org.codehaus.plexus.util.xml.pull.XmlPullParserException;
+import org.eclipse.tycho.test.AbstractTychoIntegrationTest;
+import org.junit.Test;
+import org.tukaani.xz.XZInputStream;
+
+/**
+ * Test that the goal `tycho-p2-repository:fix-artifacts-metadata` removes
+ * old checksums if they are present in the source metadata.
+ * New p2 libs are configured to not publish them anymore.
+ * <p>
+ * If not removed, they are checked during the product assembly and because
+ * they continue to keep an old value (if a IU was modified for example to
+ * (re)sign it) this step fails to complete due to checksum mismatch.
+ *
+ * See https://github.com/eclipse-tycho/tycho/issues/2875
+ */
+public class P2RepositoryFixArtifactsMetadataOldChecksumsTest extends AbstractTychoIntegrationTest {
+
+	@Test
+	public void testRemoveOldChecksumsNotRecalculated() throws Exception {
+		Verifier verifier = getVerifier("/p2Repository.fixArtifactsMetadata.oldChecksums", false);
+		verifier.executeGoals(asList("verify"));
+		verifier.verifyErrorFreeLog();
+
+		Path repositoryPath = Path.of(verifier.getBasedir(), "target/repository");
+		Path artifactPath = repositoryPath.resolve("artifacts.xml.xz");
+		assertTrue(artifactPath.toFile().isFile());
+
+		Xpp3Dom dom;
+		try (XZInputStream stream = new XZInputStream(Files.newInputStream(artifactPath))) {
+			dom = Xpp3DomBuilder.build(stream, StandardCharsets.UTF_8.displayName());
+		} catch (IOException | XmlPullParserException e) {
+			fail(e.getMessage());
+			throw e;
+		}
+
+		Map<String, String> artifactProperties = getArtifactProperties(dom, "org.slf4j.api");
+
+		String[] checksumsThatMustNotBePresent = {"download.md5", "download.checksum.md5"};
+		for(String checksumKey : checksumsThatMustNotBePresent) {
+			String checksumValue = artifactProperties.get(checksumKey);
+
+			assertNull("Property '" + checksumKey + "' is present in artifacts metadata", checksumValue);
+		}
+	}
+
+	private Map<String, String> getArtifactProperties(Xpp3Dom element, String artifactId) {
+		return Arrays.stream(element.getChild("artifacts").getChildren())
+				.filter(it -> artifactId.equals(it.getAttribute("id")))
+				.flatMap(it -> Arrays.stream(it.getChild("properties").getChildren()))
+				.collect(Collectors.toMap(it -> it.getAttribute("name"), it -> it.getAttribute("value")));
+	}
+
+}