26     S s3 {s + 2, 3};  in test()  local
42     assert( s3.contains(""));  in test()
43     assert( s3.contains("d"));  in test()
44     assert( s3.contains("e"));  in test()
45     assert( s3.contains("de"));  in test()
46     assert( s3.contains("cd"));  in test()
47     assert(!s3.contains("ce"));  in test()
48     assert( s3.contains("cde"));  in test()
49     assert(!s3.contains("edc"));  in test()
50     assert(!s3.contains("bcde"));  in test()
51     assert(!s3.contains("abcde"));  in test()
52     assert(!s3.contains("xyz"));  in test()