@Test
public void addMetafileAsChildToParent() {

    Metafile parentMetafile = vufsService.createEmptyMetafile();
    String parentMetafileUuid = parentMetafile.getFileUuid();
    Metafile childMetafile = vufsService.createEmptyMetafile();
    String childMetafileUuid = childMetafile.getFileUuid();
    assertEquals(parentMetafile.getChildFileUuidSet().size(), 0);
    assertEquals(childMetafile.getChildFileUuidSet().size(), 0);
    vufsService.addMetafileToMetatable(parentMetafile);
    boolean isAdded = vufsService.addMetafileAsChildToParent(childMetafile, parentMetafileUuid);
    assertTrue(isAdded);
    assertEquals(parentMetafile.getChildFileUuidSet().size(), 1);
    assertTrue(parentMetafile.getChildFileUuidSet().contains(childMetafileUuid));
}