Add test for JarResultBuildStep#filterJarFile

core/deployment/src/main/java/io/quarkus/deployment/pkg/steps/JarResultBuildStep.java

@@ -1236,7 +1236,7 @@ private void handleParent(FileSystem runnerZipFs, String fileName, Map<String, S
         }
     }
 
-    private void filterJarFile(Path resolvedDep, Path targetPath, Set<String> transformedFromThisArchive) {
+    static void filterJarFile(Path resolvedDep, Path targetPath, Set<String> transformedFromThisArchive) {
         try {
             byte[] buffer = new byte[10000];
             try (JarFile in = new JarFile(resolvedDep.toFile(), false)) {

core/deployment/src/test/java/io/quarkus/deployment/pkg/steps/JarResultBuildStepTest.java

@@ -0,0 +1,29 @@
+package io.quarkus.deployment.pkg.steps;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.nio.file.Path;
+import java.util.Set;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.jar.Manifest;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class JarResultBuildStepTest {
+
+    @Test
+    void should_unsign_jar_when_filtered(@TempDir Path tempDir) throws Exception {
+        Path signedJarFilePath = Path.of(getClass().getClassLoader().getResource("signed.jar").toURI());
+        Path jarFilePath = tempDir.resolve("unsigned.jar");
+        JarResultBuildStep.filterJarFile(signedJarFilePath, jarFilePath, Set.of("org/eclipse/jgit/transport/sshd/SshdSessionFactory.class"));
+        try (JarFile jarFile = new JarFile(jarFilePath.toFile())) {
+            assertThat(jarFile.stream().map(JarEntry::getName)).doesNotContain("META-INF/ECLIPSE_.RSA", "META-INF/ECLIPSE_.SF");
+            // Check that the manifest is still present
+            Manifest manifest = jarFile.getManifest();
+            assertThat(manifest.getMainAttributes()).isNotEmpty();
+            assertThat(manifest.getEntries()).isEmpty();
+        }
+    }
+}