assertEmpty(Sets.cartesianProduct(set(1), mt));
  }

  private static void assertEmpty(Set<? extends List<?>> set) {
    assertTrue(set.isEmpty());
    assertEquals(0, set.size());
    assertFalse(set.iterator().hasNext());
  }

  public void testCartesianProduct_binary1x1() {
    assertThat(Sets.cartesianProduct(set(1), set(2))).contains(list(1, 2));
  }

  public void testCartesianProduct_binary1x2() {

        List<DependencyManagement> importMgmts = null;

        List<Dependency> deps = new ArrayList<>(depMgmt.getDependencies());
        for (Iterator<Dependency> it = deps.iterator(); it.hasNext(); ) {
            Dependency dependency = it.next();

            if (!("pom".equals(dependency.getType()) && "import".equals(dependency.getScope()))
                    || "bom".equals(dependency.getType())) {

                try ( CloseableIterator<SmbResource> it = SmbEnumerationUtil
                        .doEnum(this, "*", ATTR_DIRECTORY | ATTR_HIDDEN | ATTR_SYSTEM, null, null) ) {
                    while ( it.hasNext() ) {
                        try ( SmbResource r = it.next() ) {
                            try {
                                r.delete();
                            }

          // Skip stale entry.
          return false;
        }
      } finally {
        currentSegment.postReadCleanup();
      }
    }

    @Override
    public boolean hasNext() {
      return nextExternal != null;
    }

    WriteThroughEntry nextEntry() {
      if (nextExternal == null) {
        throw new NoSuchElementException();
      }