@Test
public void shouldReturnEmptyIfInnerIsEmpty() throws Exception {

  ImmutableList<String> a = ImmutableList.of("a", "b");
  ImmutableList<Integer> b = ImmutableList.of();
  NestedLoopPairIterable<String, Integer> ible = NestedLoopPairIterable.of(a, b);
  assertEquals(0, size(ible));
}