@Test
public void testAddIdx() {

    metadata.commit(() -> {
        List<String> list = getList("prop1");
        list.add(1, "x");
        list.add(1, "y");
    }, MetadataAccess.SERVICE);
    
    metadata.read(() -> {
        List<String> list = getList("prop1");
        
        assertThat(list).contains("a", "y", "x", "b", "c");
    }, MetadataAccess.SERVICE);
}