+ "<exportedPackage>c</exportedPackage>" + "</exportedPackages>" + "<exportedArtifacts>"
                + "<exportedArtifact>x</exportedArtifact>" + "<exportedArtifact>y</exportedArtifact>"
                + "<exportedArtifact> z </exportedArtifact>" + "</exportedArtifacts>" + "</extension>";

        ExtensionDescriptor ed = builder.build(toStream(xml));

        assertNotNull(ed);

                .setName("maven");

        Set<String> exportedArtifacts = new HashSet<>(coreEntry.getExportedArtifacts());
        Set<String> exportedPackages = new HashSet<>(coreEntry.getExportedPackages());
        for (CoreExtensionEntry extension : extensions) {
            exportedArtifacts.addAll(extension.getExportedArtifacts());
            exportedPackages.addAll(extension.getExportedPackages());