String xml = "<extension></extension>";

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

        assertNotNull(ed);
        assertNotNull(ed.getExportedPackages());
        assertThat(ed.getExportedPackages(), is(empty()));
        assertNotNull(ed.getExportedArtifacts());
        assertThat(ed.getExportedArtifacts(), is(empty()));
    }

    @Test