@Test
public final void testFindCommonLineInPaths() {

    assertEquals(PathUtils.findCommonLineInPaths(path, elem4), l4);
    assertEquals(PathUtils.findCommonLineInPaths(path, elem6), l4);
    assertNull(PathUtils.findCommonLineInPaths(path, null));
    assertNull(PathUtils.findCommonLineInPaths(null, elem6));
    assertNull(PathUtils.findCommonLineInPaths(path,
            new LineLinkedListElement() {
                @Override
                public LineLinkedListElement getPrevious() {
                    return null;
                }
                @Override
                public Line getLine() {
                    return null;
                }
            }));
    assertNull(PathUtils.findCommonLineInPaths(emptyPath, elem4));
}