21   auto h1 = make_histogram(axis::regular<double,  in main()
24                                          axis::option::growth_t>{2, 0., 1.});  in main()
29   assert(h1.axis().size() == 2);  in main()
30   assert(h1.axis().bin(0).lower() == 0.0);  in main()
31   assert(h1.axis().bin(1).upper() == 1.0);  in main()
36   assert(h1.axis().size() == 3);  in main()
37   assert(h1.axis().bin(0).lower() == -0.5);  in main()
38   assert(h1.axis().bin(2).upper() == 1.0);  in main()
42   assert(h1.axis().size() == 5);  in main()
43   assert(h1.axis().bin(0).lower() == -0.5);  in main()
44   assert(h1.axis().bin(4).upper() == 2.0);  in main()
48   auto h2 = make_histogram(axis::category<std::string,  in main()
50                                           axis::option::growth_t>());  in main()