summaryrefslogtreecommitdiffhomepage
path: root/src/test-unicode.cpp
blob: a30be703445ef1c3ad90ed14427020ea7e1e550a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
#define BOOST_TEST_MODULE unicode_test

#include <boost/locale.hpp>
#include <boost/test/included/unit_test.hpp>
#include <boost/test/data/dataset.hpp>
#include <boost/test/data/monomorphic.hpp>
#include <boost/test/data/test_case.hpp>
#include <boost/timer/timer.hpp>

#include <array>
#include <chrono>
#include <codecvt>
#include <deque>
#include <exception>
#include <limits>
#include <list>
#include <locale>
#include <random>
#include <string>
#include <tuple>
#include <type_traits>
#include <vector>

#include <unicode.h>

using namespace std::chrono_literals;
using namespace std::string_literals;

typedef std::tuple<std::basic_string<utf8_t>, std::basic_string<char16_t>, std::basic_string<char32_t>> types_collection_type;

// create tuple of the same string, in UTF-8, UTF-16 and UTF-32
#define SUCCESS_TUPLE(x) {u8 ## x, u ## x, U ## x}

// Success cases: convert string to all other types, respectively
std::vector<types_collection_type> success_sets {
 SUCCESS_TUPLE(""),
 SUCCESS_TUPLE("ASCII string1"),
 SUCCESS_TUPLE("Täst just looks like German"),
 SUCCESS_TUPLE("\u732b is chinese for cat"),
 SUCCESS_TUPLE("\U0001F63A"),
 SUCCESS_TUPLE("\U0001F63A is a smiling cat"),
};

// Error cases: throwing upon convert to all other types
std::vector<std::basic_string<utf8_t>> failure_strings_char8_t {
 // using u8"" here doesn't work on MSVC
 (utf8_t*)"\x80", // utf-8 continuation byte
 (utf8_t*)"\x81", // utf-8 continuation byte
 (utf8_t*)"\xc3\xc3\xa4", // initial byte of utf-8 "ä", followed by valid utf-8 "ä"
 (utf8_t*)"\xF8\x80\x80\x80\x80", // overlong encoding
 (utf8_t*)"\xF7\xBF\xBF\xBF", // valid encoding of invalid code point
};

std::vector<std::basic_string<char16_t>> failure_strings_char16_t {
 u"\xD801", // single high surrogate
 u"\xDFFF", // single low surrogate
 u"\xDFFF\xD801", // bad surrogate pair order
};

std::vector<std::basic_string<char32_t>> failure_strings_char32_t {
 U"\xD800 and more text", // invalid unicode (surrogate half)
 U"blabla \xD801", // invalid unicode (surrogate half)
 U"moreblabla \xDFFF", // invalid unicode (surrogate half)
 U"\x10000000", // invalid unicode (number too big)
};

// output operators must be in same namespace as the type itself
namespace std {

#ifdef __cpp_char8_t
std::ostream& operator<<(std::ostream& os, std::basic_string<utf8_t> const& s)
{
 os << "[";
 for (auto& c: s)
  os << " " << std::to_string(static_cast<uint8_t>(c));
 os << "]";

 return os;
}
#endif

std::ostream& operator<<(std::ostream& os, std::basic_string<char16_t> const& s)
{
 os << "[";
 for (auto& c: s)
  os << " " << std::to_string(static_cast<uint16_t>(c));
 os << "]";

 return os;
}

std::ostream& operator<<(std::ostream& os, std::basic_string<char32_t> const& s)
{
 os << "[";
 for (auto& c: s)
  os << " " << std::to_string(static_cast<uint32_t>(c));
 os << "]";

 return os;
}

}

template<size_t i = 0, size_t j = 0, typename... Ts>
void test_utf_to_utf(std::tuple<Ts...>& t)
{
 typedef typename std::tuple_element<i,typename std::remove_reference<decltype(t)>::type>::type From;
 typedef typename std::tuple_element<j,typename std::remove_reference<decltype(t)>::type>::type To;

 // test base type interface
 To result { unicode::convert<typename From::value_type, typename To::value_type>(std::get<i>(t)) };
 BOOST_CHECK_MESSAGE(std::get<j>(t) == result, "Base: From " << typeid(typename From::value_type).name() << "(" << i << ", " << std::get<i>(t) << ") to " << typeid(typename To::value_type).name() << "(" << j << ", " << std::get<j>(t) << "), got " << result);

 // test container interface
 result = unicode::convert<From, To>(std::get<i>(t));
 BOOST_CHECK_MESSAGE(std::get<j>(t) == result, "Container: From " << typeid(From).name() << "(" << i << ", " << std::get<i>(t) << ") to " << typeid(To).name() << "(" << j << ", " << std::get<j>(t) << "), got " << result);

 // test facet interface
 result = unicode::convert<typename unicode::Encoding<typename From::value_type>::Facet, typename unicode::Encoding<typename To::value_type>::Facet>(std::get<i>(t));
 BOOST_CHECK_MESSAGE(std::get<j>(t) == result, "Facet: From " << typeid(From).name() << "(" << i << ", " << std::get<i>(t) << ") to " << typeid(To).name() << "(" << j << ", " << std::get<j>(t) << "), got " << result);
 
 // iterate over other combinations
 if constexpr (i + 1 < std::tuple_size<typename std::remove_reference<decltype(t)>::type>::value)
  test_utf_to_utf<i + 1, j>(t);
 else if constexpr (j + 1 < std::tuple_size<typename std::remove_reference<decltype(t)>::type>::value)
  test_utf_to_utf<0, j + 1>(t);
}

// We don't use BOOST_DATA_TEST_CASE here because boost::test tries to assign
// a new variable to each tuple element which we don't want
// https://lists.boost.org/boost-bugs/2016/05/45214.php

BOOST_AUTO_TEST_CASE(utf_to_utf_success)
{
 for (auto& t: success_sets)
  test_utf_to_utf(t);
}

template<size_t i = 0, typename... Ts>
void test_is_valid_utf(std::tuple<Ts...>& t)
{
 typedef typename std::tuple_element<i,typename std::remove_reference<decltype(t)>::type>::type T;

 // test via basic type
 bool result { unicode::is_valid_utf<typename T::value_type>(std::get<i>(t)) };
 BOOST_CHECK_MESSAGE(result == true, "is_valid_utf w/ " << typeid(typename T::value_type).name() << "(" << i << ", " << std::get<i>(t) << "), got " << result);

 // test via container type
 result = unicode::is_valid_utf<T>(std::get<i>(t));
 BOOST_CHECK_MESSAGE(result == true, "is_valid_utf w/ " << typeid(T).name() << "(" << i << ", " << std::get<i>(t) << "), got " << result);

 // test via Facet
 result = unicode::is_valid_utf<typename unicode::Encoding<typename T::value_type>::Facet>(std::get<i>(t));
 BOOST_CHECK_MESSAGE(result == true, "is_valid_utf w/ " << typeid(typename unicode::Encoding<typename T::value_type>::Facet).name() << "(" << i << ", " << std::get<i>(t) << "), got " << result);

 // iterate over other combinations
 if constexpr (i + 1 < std::tuple_size<typename std::remove_reference<decltype(t)>::type>::value)
  test_is_valid_utf<i + 1>(t);
}

BOOST_AUTO_TEST_CASE(is_valid_utf_success)
{
 for (auto& t: success_sets)
  test_is_valid_utf(t);
}

// iterate over std::tuple T types
template<typename From, typename Collection, size_t index = 0>
void test_utf_to_utf_failure(std::basic_string<From>& s)
{
 typedef typename std::tuple_element<index, Collection>::type::value_type To;

 // via base type
 try {
  (void) unicode::convert<From,To>(s);
  BOOST_ERROR("Base type: Expected exception at index: " << index << ", " << typeid(From).name() << " -> " << typeid(To).name());
 } catch (const std::invalid_argument&) {
  // OK: this is an expected exception for convert() on bad input
 } catch (const std::exception& ex) {
  BOOST_ERROR("Unexpected error on convert(): " << ex.what());
 };

 // via container
 try {
  (void) unicode::convert<typename unicode::Encoding<From>::Facet::string_type, typename unicode::Encoding<To>::Facet::string_type>(s);
  BOOST_ERROR("Container type: Expected exception at index: " << index << ", " << typeid(From).name() << " -> " << typeid(To).name());
 } catch (const std::invalid_argument&) {
  // OK: this is an expected exception for convert() on bad input
 } catch (const std::exception& ex) {
  BOOST_ERROR("Unexpected error on convert(): " << ex.what());
 };

 // via facet
 try {
  (void) unicode::convert<typename unicode::Encoding<From>::Facet,typename unicode::Encoding<To>::Facet>(s);
  BOOST_ERROR("Facet: Expected exception at index: " << index << ", " << typeid(From).name() << " -> " << typeid(To).name());
 } catch (const std::invalid_argument&) {
  // OK: this is an expected exception for convert() on bad input
 } catch (const std::exception& ex) {
  BOOST_ERROR("Unexpected error on convert(): " << ex.what());
 };

 // iterate over remaining types 
 if constexpr (index + 1 < std::tuple_size<Collection>::value)
  test_utf_to_utf_failure<From, Collection, index + 1>(s);
}

BOOST_AUTO_TEST_CASE(utf_to_utf_failure)
{
 for (auto& s: failure_strings_char8_t)
  test_utf_to_utf_failure<typename std::remove_reference<decltype(s)>::type::value_type, types_collection_type>(s);
 
 for (auto& s: failure_strings_char16_t)
  test_utf_to_utf_failure<typename std::remove_reference<decltype(s)>::type::value_type, types_collection_type>(s);

 for (auto& s: failure_strings_char32_t)
  test_utf_to_utf_failure<typename std::remove_reference<decltype(s)>::type::value_type, types_collection_type>(s);
}

// iterate over std::tuple T types
template<typename T, typename Collection, size_t index = 0>
void test_is_valid_utf_failure(std::basic_string<T>& s)
{
 BOOST_CHECK_MESSAGE(unicode::is_valid_utf<T>(s) == false, "Expected bad UTF at index: " << index << ", " << typeid(T).name());
 
 BOOST_CHECK_MESSAGE(unicode::is_valid_utf<typename std::basic_string<T>>(s) == false, "Expected bad UTF at index: " << index << ", " << typeid(T).name());
 
 BOOST_CHECK_MESSAGE(unicode::is_valid_utf<typename unicode::Encoding<T>::Facet>(s) == false, "Expected bad UTF at index: " << index << ", " << typeid(typename unicode::Encoding<T>::Facet).name());

 // iterate over remaining types 
 if constexpr (index + 1 < std::tuple_size<Collection>::value)
  test_is_valid_utf_failure<T, Collection, index + 1>(s);
}

BOOST_AUTO_TEST_CASE(is_valid_utf_failure)
{
 for (auto& s: failure_strings_char8_t)
  test_is_valid_utf_failure<typename std::remove_reference<decltype(s)>::type::value_type, types_collection_type>(s);
 
 for (auto& s: failure_strings_char16_t)
  test_is_valid_utf_failure<typename std::remove_reference<decltype(s)>::type::value_type, types_collection_type>(s);

 for (auto& s: failure_strings_char32_t)
  test_is_valid_utf_failure<typename std::remove_reference<decltype(s)>::type::value_type, types_collection_type>(s);
}

BOOST_AUTO_TEST_CASE(is_valid_unicode)
{
 BOOST_CHECK(unicode::is_valid_unicode('\0'));
 BOOST_CHECK(unicode::is_valid_unicode(U'a'));
 BOOST_CHECK(unicode::is_valid_unicode(U'ä'));
 BOOST_CHECK(unicode::is_valid_unicode(U'\u732b')); // cat chinese
 BOOST_CHECK(unicode::is_valid_unicode(U'\U0001F63A')); // cat chinese
 BOOST_CHECK(unicode::is_valid_unicode(0x0001F63A)); // cat smiley

 BOOST_CHECK(!unicode::is_valid_unicode(0x00110000));
 BOOST_CHECK(!unicode::is_valid_unicode(0xFFFFFFFF)); // U"\UFFFFFFFF" is invalid C++
 BOOST_CHECK(!unicode::is_valid_unicode(0x01234567));
 BOOST_CHECK(!unicode::is_valid_unicode(0x12345678));
 BOOST_CHECK(!unicode::is_valid_unicode(0xD800));
 BOOST_CHECK(!unicode::is_valid_unicode(0xD987));
 BOOST_CHECK(!unicode::is_valid_unicode(0xDFFF));
}

struct random_context {
 random_context(int max_value = 0x10FFFF - 0x800): code_point_distribution(0, max_value) {}
 std::random_device rd;  // OS random number engine to seed RNG (below)
 std::mt19937 gen{rd()};
 std::uniform_int_distribution<size_t> sequence_length{0, 100000}; // length of sequence: 0 ... 100000 code units
 std::uniform_int_distribution<unsigned long> code_point_distribution;
};

// generates valid and invalid strings of different type
template<typename T>
T generate_random_invalid(random_context& rc, size_t length)
{
 // Using unsigned long for std::uniform_int_distribution<> because it needs to be basic type according to MSVC
 std::uniform_int_distribution<unsigned long> code_unit{0, std::numeric_limits<typename T::value_type>::max()}; // code unit value
 T result;
 std::generate_n(std::back_inserter(result), length, [&](){return static_cast<typename T::value_type>(code_unit(rc.gen));});

 return result;
}

char32_t generate_random_char(random_context& rc)
{
 auto result {rc.code_point_distribution(rc.gen)};
 if (result >= 0xD800)
  result += 0x800;
 return static_cast<char32_t>(result);
}

std::u32string generate_random_string(random_context& rc, size_t length)
{
 std::u32string result;
 std::generate_n(std::back_inserter(result), length, [&](){return generate_random_char(rc);});

 return result;
}

template<typename From, typename ToTypesCollectionType, size_t i = 0>
void test_random_invalid(random_context& rc, size_t length)
{
 //std::cerr << "LENGTH: " << length << std::endl;
 typedef typename std::tuple_element<i,ToTypesCollectionType>::type To;

 From r {static_cast<From>(generate_random_invalid<From>(rc, length))};

 // base type interface
 try {
  To result{unicode::convert<typename From::value_type,typename To::value_type>(r)};

  if (r.empty()) {
   BOOST_CHECK(result.empty());
  } else {
   BOOST_CHECK(!result.empty());
  }
 } catch (const std::invalid_argument&) {
  // OK: this is an expected exception for convert() on bad input
 } catch (const std::exception& ex) {
  BOOST_ERROR("Unexpected error on convert(): " << ex.what());
 }

 // container type interface
 try {
  To result{unicode::convert<From, To>(r)};

  if (r.empty()) {
   BOOST_CHECK(result.empty());
  } else {
   BOOST_CHECK(!result.empty());
  }
 } catch (const std::invalid_argument&) {
  // OK: this is an expected exception for convert() on bad input
 } catch (const std::exception& ex) {
  BOOST_ERROR("Unexpected error on convert(): " << ex.what());
 }

 // facet interface
 try {
  To result{unicode::convert<typename unicode::Encoding<typename From::value_type>::Facet,typename unicode::Encoding<typename To::value_type>::Facet>(r)};

  if (r.empty()) {
   BOOST_CHECK(result.empty());
  } else {
   BOOST_CHECK(!result.empty());
  }
 } catch (const std::invalid_argument&) {
  // OK: this is an expected exception for convert() on bad input
 } catch (const std::exception& ex) {
  BOOST_ERROR("Unexpected error on convert(): " << ex.what());
 }

 // iterate over remaining To types
 if constexpr (i + 1 < std::tuple_size<ToTypesCollectionType>::value)
  test_random_invalid<From, ToTypesCollectionType, i + 1>(rc, length);
}

BOOST_AUTO_TEST_CASE_TEMPLATE(random_sequences_invalid, T, types_collection_type)
{
 random_context rc;

 for (int i = 0; i < 10; i++) {
  test_random_invalid<T,types_collection_type>(rc, rc.sequence_length(rc.gen));
 }
}

// utility wrapper to adapt locale-bound facets for wstring/wbuffer convert
template<class Facet>
struct deletable_facet : Facet
{
    template<class ...Args>
    deletable_facet(Args&& ...args) : Facet(std::forward<Args>(args)...) {}
    ~deletable_facet() {}
};

namespace {
 // char8_t instead of char doesn't work w/ clang++-13 + C++20 (yet?)
 std::wstring_convert<deletable_facet<std::codecvt<char16_t, char, std::mbstate_t>>, char16_t> conv16;
 std::wstring_convert<deletable_facet<std::codecvt<char32_t, char, std::mbstate_t>>, char32_t> conv32;

 template<typename From, typename To>
 std::basic_string<To> std_convert(const std::basic_string<From>& s);

 template<>
 std::basic_string<utf8_t> std_convert<utf8_t, utf8_t>(const std::basic_string<utf8_t>& s)
 {
  std::string a{s.begin(), s.end()};
  a = conv32.to_bytes(conv32.from_bytes(a));
  return std::basic_string<utf8_t>{a.begin(), a.end()};
 }

 template<>
 std::basic_string<char16_t> std_convert<utf8_t, char16_t>(const std::basic_string<utf8_t>& s)
 {
  std::string a{s.begin(), s.end()};
  return conv16.from_bytes(a);
 }

 template<>
 std::basic_string<char32_t> std_convert<utf8_t, char32_t>(const std::basic_string<utf8_t>& s)
 {
  std::string a{s.begin(), s.end()};
  return conv32.from_bytes(a);
 }

 template<>
 std::basic_string<utf8_t> std_convert<char16_t, utf8_t>(const std::basic_string<char16_t>& s)
 {
  auto result{conv16.to_bytes(s)};
  return std::basic_string<utf8_t>(result.begin(), result.end());
 }

 template<>
 std::basic_string<char16_t> std_convert<char16_t, char16_t>(const std::basic_string<char16_t>& s)
 {
  return conv16.from_bytes(conv16.to_bytes(s));
 }

 template<>
 std::basic_string<char32_t> std_convert<char16_t, char32_t>(const std::basic_string<char16_t>& s)
 {
  return conv32.from_bytes(conv16.to_bytes(s));
 }

 template<>
 std::basic_string<utf8_t> std_convert<char32_t, utf8_t>(const std::basic_string<char32_t>& s)
 {
  auto result{conv32.to_bytes(s)};
  return std::basic_string<utf8_t>(result.begin(), result.end());
 }

 template<>
 std::basic_string<char16_t> std_convert<char32_t, char16_t>(const std::basic_string<char32_t>& s)
 {
  return conv16.from_bytes(conv32.to_bytes(s));
 }

 template<>
 std::basic_string<char32_t> std_convert<char32_t, char32_t>(const std::basic_string<char32_t>& s)
 {
  return conv32.from_bytes(conv32.to_bytes(s));
 }
}

class CPUTimer
{
public:
 CPUTimer(const std::string& name = "Timer"): mName(name), mWallTime0(std::chrono::steady_clock::now())
 {
 }

 ~CPUTimer()
 {
  auto elapsed_cpu{mCPUTimer.elapsed()};
  std::cout << mName << ": " << std::chrono::duration<double>(std::chrono::steady_clock::now() - mWallTime0).count() <<
   "s (" << (double(elapsed_cpu.user + elapsed_cpu.system) / 1000000000) <<
   "s CPU)" << std::endl;
 }

private:
 std::string mName;
 std::chrono::time_point<std::chrono::steady_clock> mWallTime0;
 boost::timer::cpu_timer mCPUTimer;
};

template<typename From, typename ToTypesCollectionType, size_t index = 0>
void test_random_valid(random_context& rc, size_t length, const std::string& description)
{
 typedef typename std::tuple_element<index,ToTypesCollectionType>::type To;

 // Fill UTF-32 data list: source for tests
 std::vector<std::u32string> u32list;
 std::generate_n(std::back_inserter(u32list), 1000, [&](){return generate_random_string(rc, rc.sequence_length(rc.gen));});

 // Fill From data list
 std::vector<From> list;
 std::transform(u32list.begin(), u32list.end(), std::back_inserter(list), [](const std::u32string& s){
  return unicode::convert<unicode::UTF_32, typename unicode::Encoding<typename From::value_type>::Facet>(s);
 });

 for (int i = 0; i < list.size(); i++) {
  BOOST_CHECK(list[i].size() >= u32list[i].size());
  To result{unicode::convert<typename unicode::Encoding<typename From::value_type>::Facet,typename unicode::Encoding<typename To::value_type>::Facet>(list[i])};
  BOOST_CHECK(result.size() >= u32list[i].size());
  auto boost_result{boost::locale::conv::utf_to_utf<typename To::value_type, typename From::value_type>(list[i])};
  BOOST_CHECK_EQUAL(result, boost_result);
 }
 
 {
  CPUTimer timer("Performance test for converting "s + std::to_string(list.size()) +
   " "s + description +
   " from UTF-"s + std::to_string(sizeof(typename From::value_type) * 8) +
   " to UTF-"s + std::to_string(sizeof(typename To::value_type) * 8));
  for (const auto& i: list)
   To result{unicode::convert<typename unicode::Encoding<typename From::value_type>::Facet,typename unicode::Encoding<typename To::value_type>::Facet>(i)};
 }
 
 {
  CPUTimer timer("  -> Compare to boost::locale::conv::utf_to_utf");
  for (const auto& i: list)
   To result{boost::locale::conv::utf_to_utf<typename To::value_type, typename From::value_type>(i)};
 }

 {
  CPUTimer timer("  -> Compare to std::wstring_convert");
  for (const auto& i: list)
   To result{std_convert<typename From::value_type, typename To::value_type>(i)};
 }

 // iterate over remaining To types
 if constexpr (index + 1 < std::tuple_size<ToTypesCollectionType>::value)
  test_random_valid<From, ToTypesCollectionType, index + 1>(rc, length, description);
}

BOOST_AUTO_TEST_CASE_TEMPLATE(random_sequences_valid_all_unicode, T, types_collection_type)
{
 random_context rc;

 test_random_valid<T,types_collection_type>(rc, rc.sequence_length(rc.gen), "All Unicode strings");
}

BOOST_AUTO_TEST_CASE_TEMPLATE(random_sequences_valid_ascii, T, types_collection_type)
{
 random_context rc{127};

 test_random_valid<T,types_collection_type>(rc, rc.sequence_length(rc.gen), "ASCII only strings");
}

// Test ISO and UTF encodings
BOOST_AUTO_TEST_CASE(convert)
{
 BOOST_CHECK((std::string{unicode::convert<unicode::ISO_8859_1,unicode::ISO_8859_1>({})}) == std::string{});
 BOOST_CHECK((std::string{unicode::convert<unicode::ISO_8859_1,unicode::ISO_8859_1>("abc")}) == std::string{"abc"});
 BOOST_CHECK((std::string{unicode::convert<unicode::ISO_8859_1,unicode::ISO_8859_1>("äöü")}) == std::string{"äöü"});
 BOOST_CHECK((std::string{unicode::convert<unicode::ISO_8859_1,unicode::ISO_8859_1>("\xa4")}) == std::string{"\xa4"}); // €
 
 BOOST_CHECK((std::string{unicode::convert<unicode::ISO_8859_15,unicode::ISO_8859_15>("\xa4")}) == std::string{"\xa4"}); // €
 
 BOOST_CHECK_THROW(((void)std::string{unicode::convert<unicode::ISO_8859_15,unicode::ISO_8859_1>("\xa4")}), std::invalid_argument); // € not available in ISO-8859-1
 
 BOOST_CHECK_THROW(((void)std::string{unicode::convert<unicode::UTF_8,unicode::ISO_8859_1>(u8"\u20ac")}), std::invalid_argument);
 BOOST_CHECK_THROW(((void)std::string{unicode::convert<unicode::UTF_16,unicode::ISO_8859_1>(u"\u20ac")}), std::invalid_argument);
 BOOST_CHECK_THROW(((void)std::string{unicode::convert<unicode::UTF_32,unicode::ISO_8859_1>(U"\u20ac")}), std::invalid_argument);
 BOOST_CHECK_THROW(((void)std::string{unicode::convert<unicode::UTF_8,unicode::ISO_8859_15>(u8"\u732b")}), std::invalid_argument);
 BOOST_CHECK_THROW(((void)std::string{unicode::convert<unicode::UTF_16,unicode::ISO_8859_15>(u"\u732b")}), std::invalid_argument);
 BOOST_CHECK_THROW(((void)std::string{unicode::convert<unicode::UTF_32,unicode::ISO_8859_15>(U"\u732b")}), std::invalid_argument);

 BOOST_CHECK_THROW((unicode::convert<unicode::UTF_32,unicode::UTF_8>(std::u32string{(char32_t*)"\x00\xD8\x00\x00\x00\x00\x00\x00"})) , std::invalid_argument);

 BOOST_CHECK((unicode::convert<unicode::UTF_8,unicode::UTF_16>(u8"abc")) == std::u16string{u"abc"});
 BOOST_CHECK((unicode::convert<unicode::UTF_32,unicode::UTF_16>(U"abc")) == std::u16string{u"abc"});

 BOOST_CHECK((unicode::convert<utf8_t,char16_t>(u8"abc")) == std::u16string{u"abc"});
 BOOST_CHECK((unicode::convert<char32_t,char16_t>(U"abc")) == std::u16string{u"abc"});

 BOOST_CHECK((unicode::convert<char, char32_t>("äöü")) == std::u32string{U"äöü"});

#ifdef _WIN32
 BOOST_CHECK(sizeof(wchar_t) == 2);
#else // Unix like
 BOOST_CHECK(sizeof(wchar_t) == 4);
#endif

 // For the following checks, wchar_t size and encoding is system dependent:
 // Windows: UTF-16
 // Linux: UTF-32
 BOOST_CHECK((unicode::convert<char, wchar_t>("äöü")) == std::wstring{L"äöü"});
 BOOST_CHECK((unicode::convert<char, wchar_t>("\u732b")) == std::wstring{L"\u732b"});
 BOOST_CHECK((unicode::convert<char, wchar_t>("\U0001F63A")) == std::wstring{L"\U0001F63A"});
 BOOST_CHECK((unicode::convert<wchar_t, char32_t>(L"\U0001F63A")) == std::u32string{U"\U0001F63A"});
 BOOST_CHECK((unicode::convert<wchar_t, utf8_t>(L"\U0001F63A")) == std::basic_string<utf8_t>{(utf8_t*)"\U0001F63A"});

 BOOST_CHECK((unicode::convert<std::string, std::wstring>(std::string{"äöü"})) == std::wstring{L"äöü"});
 
 BOOST_CHECK((unicode::convert<std::vector<char>, std::vector<wchar_t>>(std::vector<char>{})) == std::vector<wchar_t>{});
 BOOST_CHECK((unicode::convert<std::vector<char>, std::vector<wchar_t>>(std::vector<char>{'\xc3', '\xa4', '\xc3', '\xb6', '\xc3', '\xbc'})) == (std::vector<wchar_t>{L'ä', L'ö', L'ü'}));
 
 // deque
 BOOST_CHECK((unicode::convert<std::deque<char>, std::deque<wchar_t>>(std::deque<char>{})) == std::deque<wchar_t>{});
 BOOST_CHECK((unicode::convert<std::deque<char>, std::deque<wchar_t>>(std::deque<char>{'\xc3', '\xa4', '\xc3', '\xb6', '\xc3', '\xbc'})) == (std::deque<wchar_t>{L'ä', L'ö', L'ü'}));
 // yet unsupported:
 //BOOST_CHECK((unicode::convert<utf8_t, char16_t>(std::deque<utf8_t>{u8'\xc3', u8'\xa4', u8'\xc3', u8'\xb6', u8'\xc3', u8'\xbc'})) == (std::deque<char16_t>{u'ä', u'ö', u'ü'}));
 //BOOST_CHECK((unicode::convert<unicode::UTF_8, unicode::UTF_16>(std::deque<utf8_t>{u8'\xc3', u8'\xa4', u8'\xc3', u8'\xb6', u8'\xc3', u8'\xbc'})) == (std::deque<char16_t>{u'ä', u'ö', u'ü'}));
 
 // deque with uint8_t, uint16_t
 BOOST_CHECK((unicode::convert<std::deque<uint8_t>, std::deque<uint16_t>>(std::deque<uint8_t>{})) == std::deque<uint16_t>{});
 BOOST_CHECK((unicode::convert<std::deque<uint8_t>, std::deque<uint16_t>>(std::deque<uint8_t>{0xc3, 0xa4, 0xc3, 0xb6, 0xc3, 0xbc})) == (std::deque<uint16_t>{L'ä', L'ö', L'ü'}));
 
 // deque with int8_t, int16_t
 BOOST_CHECK((unicode::convert<std::deque<int8_t>, std::deque<int16_t>>(std::deque<int8_t>{
                                                                        static_cast<int8_t>(0xc3),
                                                                        static_cast<int8_t>(0xa4),
                                                                        static_cast<int8_t>(0xc3),
                                                                        static_cast<int8_t>(0xb6),
                                                                        static_cast<int8_t>(0xc3),
                                                                        static_cast<int8_t>(0xbc)})) == (std::deque<int16_t>{L'ä', L'ö', L'ü'}));
 
 // list
 BOOST_CHECK((unicode::convert<std::list<uint8_t>, std::list<uint16_t>>(std::list<uint8_t>{})) == std::list<uint16_t>{});
 BOOST_CHECK((unicode::convert<std::list<uint8_t>, std::list<uint16_t>>(std::list<uint8_t>{0xc3, 0xa4, 0xc3, 0xb6, 0xc3, 0xbc})) == (std::list<uint16_t>{L'ä', L'ö', L'ü'}));

 // list -> deque
 BOOST_CHECK((unicode::convert<std::list<uint8_t>, std::deque<uint16_t>>(std::list<uint8_t>{})) == std::deque<uint16_t>{});
 BOOST_CHECK((unicode::convert<std::list<uint8_t>, std::deque<uint16_t>>(std::list<uint8_t>{0xc3, 0xa4, 0xc3, 0xb6, 0xc3, 0xbc})) == (std::deque<uint16_t>{L'ä', L'ö', L'ü'}));
 
 // array
 BOOST_CHECK((unicode::convert<std::array<uint8_t, 0>, std::list<uint16_t>>(std::array<uint8_t, 0>{})) == std::list<uint16_t>{});
 BOOST_CHECK((unicode::convert<std::array<uint8_t, 6>, std::list<uint16_t>>(std::array<uint8_t, 6>{0xc3, 0xa4, 0xc3, 0xb6, 0xc3, 0xbc})) == (std::list<uint16_t>{L'ä', L'ö', L'ü'}));
}

BOOST_AUTO_TEST_CASE(is_valid_utf)
{
 BOOST_CHECK(unicode::is_valid_utf<char16_t>(u"äöü"));

 BOOST_CHECK(unicode::is_valid_utf<unicode::UTF_8>(u8"äöü"));
}

// check assumptions about environment
BOOST_AUTO_TEST_CASE(string_u8string)
{
 std::string a{"\xc3\xa4"};

 std::basic_string<utf8_t> b{a.begin(), a.end()};

 BOOST_CHECK(b == std::basic_string<utf8_t>{u8"ä"});
 
 a = std::string{b.begin(), b.end()};
 
 BOOST_CHECK(a == std::string{"\xc3\xa4"});

 BOOST_CHECK(sizeof(size_t) == 4 || sizeof(size_t) == 8);

 std::cout << "Detected CPU Accu size: " << (sizeof(size_t) * 8) << std::endl;
}

// check environment: demonstrate how boost convert u8->u8 throws exception on invalid input
BOOST_AUTO_TEST_CASE(utf_to_utf_failure_boost_u8_u8)
{
 for (auto& s: failure_strings_char8_t) {
  try {
   auto result1{boost::locale::conv::utf_to_utf<utf8_t, utf8_t>(s, boost::locale::conv::stop)};
   BOOST_FAIL("Expected boost convert to fail");
  } catch(...) {
   // expected
  }
 }
}

// check environment: demonstrate how boost convert u8->u16 throws exception on invalid input
BOOST_AUTO_TEST_CASE(utf_to_utf_failure_boost_u8_u16)
{
 for (auto& s: failure_strings_char8_t) {
  try {
   auto result1{boost::locale::conv::utf_to_utf<char16_t, utf8_t>(s, boost::locale::conv::stop)};
   BOOST_FAIL("Expected boost convert to fail");
  } catch(...) {
   // expected
  }
 }
}

// check environment: demonstrate how std u8->u8 throws exception on invalid input
BOOST_AUTO_TEST_CASE(utf_to_utf_failure_std_u8_u8)
{
 for (auto& s: failure_strings_char8_t) {
  try {
   auto result2{std_convert<utf8_t, utf8_t>(s)};
   BOOST_FAIL("Expected std_convert to fail");
  } catch(...) {
   // expected
  }

 }
}

// check environment: demonstrate how std u8->u16 throws exception on invalid input
BOOST_AUTO_TEST_CASE(utf_to_utf_failure_std_u8_u16)
{
 for (auto& s: failure_strings_char8_t) {
  try {
   auto result2{std_convert<utf8_t, char16_t>(s)};
   BOOST_FAIL("Expected std_convert to fail");
  } catch(...) {
   // expected
  }

 }
}