@Test
public void testIntersect() {

    Concept intersect = S.intersect(T);
    assertEquals(intersect.extent(), bits());
    assertEquals(intersect.intent(), bits(0, 1, 3));
    intersect = T.intersect(S);
    assertEquals(intersect.intent(), bits(0, 1, 3));
    intersect = W.intersect(W);
    assertEquals(intersect.intent(), W.intent());
    intersect = W.intersect(X);
    assertEquals(intersect.intent(), bits());
    intersect = X.intersect(S);
    assertEquals(intersect.intent(), X.intent());
}