@Test
public void testLazyFilter() {

  assertEquals(5, mlazy(intRangeE(0, 10)).filter(Booleans.lt(5)).eval().size());
  assertEquals(10, mlazy(intRangeE(0, 10)).filter(Booleans.lt(100)).eval().size());
  assertEquals(0, mlazy(intRangeE(0, 10)).filter(Booleans.lt(0)).eval().size());
}