@Test
public void testAddAll() {

    metadata.commit(() -> {
        List<String> list = getList("prop1");
        boolean result = list.addAll(Arrays.asList("x", "y", "z"));
        
        assertThat(result).isTrue();
    }, MetadataAccess.SERVICE);
    
    metadata.read(() -> {
        List<String> list = getList("prop1");
        
        assertThat(list).contains("a", "b", "c", "x", "y", "z");
    }, MetadataAccess.SERVICE);
}