about summary refs log blame commit diff
path: root/absl/time/duration_test.cc
blob: 775da91e6929cb0934a6189fabdb2c573210d45d (plain) (tree)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299













                                                                           
                                         


                  
                  
                 
                 




































                                                                               










                                                                      


















































                                                               















                                                                         











                                         
                    
                         

                                                       




                                                


                                                       



                                                 



                                                              


                                            




                                                                   

                                          





                                                                        
                                        






                                                                              









                                        














































































































































                                                                                
                                  
                      
                                                                               
                                                                               







                                                                               

































                                                                               
                                                                     


































































                                                                         



                                                                
































                                                                 



                                                                 














































































































































































































                                                                             
                                             




                                    
                                         















































                                                                      

                                                      






















































































































































































































































































































































































































































































































































                                                                                









                                                                  




























                                                                         















































































                                                                                



















































































































































































































































                                                                                
                                                














                                              





                                                                 






























                                                                            





                                                                            



















































                                                                               
 
               
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <chrono>  // NOLINT(build/c++11)
#include <cmath>
#include <cstdint>
#include <ctime>
#include <iomanip>
#include <limits>
#include <random>
#include <string>

#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "absl/time/time.h"

namespace {

constexpr int64_t kint64max = std::numeric_limits<int64_t>::max();
constexpr int64_t kint64min = std::numeric_limits<int64_t>::min();

// Approximates the given number of years. This is only used to make some test
// code more readable.
absl::Duration ApproxYears(int64_t n) { return absl::Hours(n) * 365 * 24; }

// A gMock matcher to match timespec values. Use this matcher like:
// timespec ts1, ts2;
// EXPECT_THAT(ts1, TimespecMatcher(ts2));
MATCHER_P(TimespecMatcher, ts, "") {
  if (ts.tv_sec == arg.tv_sec && ts.tv_nsec == arg.tv_nsec)
    return true;
  *result_listener << "expected: {" << ts.tv_sec << ", " << ts.tv_nsec << "} ";
  *result_listener << "actual: {" << arg.tv_sec << ", " << arg.tv_nsec << "}";
  return false;
}

// A gMock matcher to match timeval values. Use this matcher like:
// timeval tv1, tv2;
// EXPECT_THAT(tv1, TimevalMatcher(tv2));
MATCHER_P(TimevalMatcher, tv, "") {
  if (tv.tv_sec == arg.tv_sec && tv.tv_usec == arg.tv_usec)
    return true;
  *result_listener << "expected: {" << tv.tv_sec << ", " << tv.tv_usec << "} ";
  *result_listener << "actual: {" << arg.tv_sec << ", " << arg.tv_usec << "}";
  return false;
}

TEST(Duration, ConstExpr) {
  constexpr absl::Duration d0 = absl::ZeroDuration();
  static_assert(d0 == absl::ZeroDuration(), "ZeroDuration()");
  constexpr absl::Duration d1 = absl::Seconds(1);
  static_assert(d1 == absl::Seconds(1), "Seconds(1)");
  static_assert(d1 != absl::ZeroDuration(), "Seconds(1)");
  constexpr absl::Duration d2 = absl::InfiniteDuration();
  static_assert(d2 == absl::InfiniteDuration(), "InfiniteDuration()");
  static_assert(d2 != absl::ZeroDuration(), "InfiniteDuration()");
}

TEST(Duration, ValueSemantics) {
  // If this compiles, the test passes.
  constexpr absl::Duration a;      // Default construction
  constexpr absl::Duration b = a;  // Copy construction
  constexpr absl::Duration c(b);   // Copy construction (again)

  absl::Duration d;
  d = c;  // Assignment
}

TEST(Duration, Factories) {
  constexpr absl::Duration zero = absl::ZeroDuration();
  constexpr absl::Duration nano = absl::Nanoseconds(1);
  constexpr absl::Duration micro = absl::Microseconds(1);
  constexpr absl::Duration milli = absl::Milliseconds(1);
  constexpr absl::Duration sec = absl::Seconds(1);
  constexpr absl::Duration min = absl::Minutes(1);
  constexpr absl::Duration hour = absl::Hours(1);

  EXPECT_EQ(zero, absl::Duration());
  EXPECT_EQ(zero, absl::Seconds(0));
  EXPECT_EQ(nano, absl::Nanoseconds(1));
  EXPECT_EQ(micro, absl::Nanoseconds(1000));
  EXPECT_EQ(milli, absl::Microseconds(1000));
  EXPECT_EQ(sec, absl::Milliseconds(1000));
  EXPECT_EQ(min, absl::Seconds(60));
  EXPECT_EQ(hour, absl::Minutes(60));

  // Tests factory limits
  const absl::Duration inf = absl::InfiniteDuration();

  EXPECT_GT(inf, absl::Seconds(kint64max));
  EXPECT_LT(-inf, absl::Seconds(kint64min));
  EXPECT_LT(-inf, absl::Seconds(-kint64max));

  EXPECT_EQ(inf, absl::Minutes(kint64max));
  EXPECT_EQ(-inf, absl::Minutes(kint64min));
  EXPECT_EQ(-inf, absl::Minutes(-kint64max));
  EXPECT_GT(inf, absl::Minutes(kint64max / 60));
  EXPECT_LT(-inf, absl::Minutes(kint64min / 60));
  EXPECT_LT(-inf, absl::Minutes(-kint64max / 60));

  EXPECT_EQ(inf, absl::Hours(kint64max));
  EXPECT_EQ(-inf, absl::Hours(kint64min));
  EXPECT_EQ(-inf, absl::Hours(-kint64max));
  EXPECT_GT(inf, absl::Hours(kint64max / 3600));
  EXPECT_LT(-inf, absl::Hours(kint64min / 3600));
  EXPECT_LT(-inf, absl::Hours(-kint64max / 3600));
}

TEST(Duration, ToConversion) {
#define TEST_DURATION_CONVERSION(UNIT)                                  \
  do {                                                                  \
    const absl::Duration d = absl::UNIT(1.5);                           \
    constexpr absl::Duration z = absl::ZeroDuration();                  \
    constexpr absl::Duration inf = absl::InfiniteDuration();            \
    constexpr double dbl_inf = std::numeric_limits<double>::infinity(); \
    EXPECT_EQ(kint64min, absl::ToInt64##UNIT(-inf));                    \
    EXPECT_EQ(-1, absl::ToInt64##UNIT(-d));                             \
    EXPECT_EQ(0, absl::ToInt64##UNIT(z));                               \
    EXPECT_EQ(1, absl::ToInt64##UNIT(d));                               \
    EXPECT_EQ(kint64max, absl::ToInt64##UNIT(inf));                     \
    EXPECT_EQ(-dbl_inf, absl::ToDouble##UNIT(-inf));                    \
    EXPECT_EQ(-1.5, absl::ToDouble##UNIT(-d));                          \
    EXPECT_EQ(0, absl::ToDouble##UNIT(z));                              \
    EXPECT_EQ(1.5, absl::ToDouble##UNIT(d));                            \
    EXPECT_EQ(dbl_inf, absl::ToDouble##UNIT(inf));                      \
  } while (0)

  TEST_DURATION_CONVERSION(Nanoseconds);
  TEST_DURATION_CONVERSION(Microseconds);
  TEST_DURATION_CONVERSION(Milliseconds);
  TEST_DURATION_CONVERSION(Seconds);
  TEST_DURATION_CONVERSION(Minutes);
  TEST_DURATION_CONVERSION(Hours);

#undef TEST_DURATION_CONVERSION
}

template <int64_t N>
void TestToConversion() {
  constexpr absl::Duration nano = absl::Nanoseconds(N);
  EXPECT_EQ(N, absl::ToInt64Nanoseconds(nano));
  EXPECT_EQ(0, absl::ToInt64Microseconds(nano));
  EXPECT_EQ(0, absl::ToInt64Milliseconds(nano));
  EXPECT_EQ(0, absl::ToInt64Seconds(nano));
  EXPECT_EQ(0, absl::ToInt64Minutes(nano));
  EXPECT_EQ(0, absl::ToInt64Hours(nano));
  const absl::Duration micro = absl::Microseconds(N);
  EXPECT_EQ(N * 1000, absl::ToInt64Nanoseconds(micro));
  EXPECT_EQ(N, absl::ToInt64Microseconds(micro));
  EXPECT_EQ(0, absl::ToInt64Milliseconds(micro));
  EXPECT_EQ(0, absl::ToInt64Seconds(micro));
  EXPECT_EQ(0, absl::ToInt64Minutes(micro));
  EXPECT_EQ(0, absl::ToInt64Hours(micro));
  const absl::Duration milli = absl::Milliseconds(N);
  EXPECT_EQ(N * 1000 * 1000, absl::ToInt64Nanoseconds(milli));
  EXPECT_EQ(N * 1000, absl::ToInt64Microseconds(milli));
  EXPECT_EQ(N, absl::ToInt64Milliseconds(milli));
  EXPECT_EQ(0, absl::ToInt64Seconds(milli));
  EXPECT_EQ(0, absl::ToInt64Minutes(milli));
  EXPECT_EQ(0, absl::ToInt64Hours(milli));
  const absl::Duration sec = absl::Seconds(N);
  EXPECT_EQ(N * 1000 * 1000 * 1000, absl::ToInt64Nanoseconds(sec));
  EXPECT_EQ(N * 1000 * 1000, absl::ToInt64Microseconds(sec));
  EXPECT_EQ(N * 1000, absl::ToInt64Milliseconds(sec));
  EXPECT_EQ(N, absl::ToInt64Seconds(sec));
  EXPECT_EQ(0, absl::ToInt64Minutes(sec));
  EXPECT_EQ(0, absl::ToInt64Hours(sec));
  const absl::Duration min = absl::Minutes(N);
  EXPECT_EQ(N * 60 * 1000 * 1000 * 1000, absl::ToInt64Nanoseconds(min));
  EXPECT_EQ(N * 60 * 1000 * 1000, absl::ToInt64Microseconds(min));
  EXPECT_EQ(N * 60 * 1000, absl::ToInt64Milliseconds(min));
  EXPECT_EQ(N * 60, absl::ToInt64Seconds(min));
  EXPECT_EQ(N, absl::ToInt64Minutes(min));
  EXPECT_EQ(0, absl::ToInt64Hours(min));
  const absl::Duration hour = absl::Hours(N);
  EXPECT_EQ(N * 60 * 60 * 1000 * 1000 * 1000, absl::ToInt64Nanoseconds(hour));
  EXPECT_EQ(N * 60 * 60 * 1000 * 1000, absl::ToInt64Microseconds(hour));
  EXPECT_EQ(N * 60 * 60 * 1000, absl::ToInt64Milliseconds(hour));
  EXPECT_EQ(N * 60 * 60, absl::ToInt64Seconds(hour));
  EXPECT_EQ(N * 60, absl::ToInt64Minutes(hour));
  EXPECT_EQ(N, absl::ToInt64Hours(hour));
}

TEST(Duration, ToConversionDeprecated) {
  TestToConversion<43>();
  TestToConversion<1>();
  TestToConversion<0>();
  TestToConversion<-1>();
  TestToConversion<-43>();
}

template <int64_t N>
void TestFromChronoBasicEquality() {
  using std::chrono::nanoseconds;
  using std::chrono::microseconds;
  using std::chrono::milliseconds;
  using std::chrono::seconds;
  using std::chrono::minutes;
  using std::chrono::hours;

  static_assert(absl::Nanoseconds(N) == absl::FromChrono(nanoseconds(N)), "");
  static_assert(absl::Microseconds(N) == absl::FromChrono(microseconds(N)), "");
  static_assert(absl::Milliseconds(N) == absl::FromChrono(milliseconds(N)), "");
  static_assert(absl::Seconds(N) == absl::FromChrono(seconds(N)), "");
  static_assert(absl::Minutes(N) == absl::FromChrono(minutes(N)), "");
  static_assert(absl::Hours(N) == absl::FromChrono(hours(N)), "");
}

TEST(Duration, FromChrono) {
  TestFromChronoBasicEquality<-123>();
  TestFromChronoBasicEquality<-1>();
  TestFromChronoBasicEquality<0>();
  TestFromChronoBasicEquality<1>();
  TestFromChronoBasicEquality<123>();

  // Minutes (might, depending on the platform) saturate at +inf.
  const auto chrono_minutes_max = std::chrono::minutes::max();
  const auto minutes_max = absl::FromChrono(chrono_minutes_max);
  const int64_t minutes_max_count = chrono_minutes_max.count();
  if (minutes_max_count > kint64max / 60) {
    EXPECT_EQ(absl::InfiniteDuration(), minutes_max);
  } else {
    EXPECT_EQ(absl::Minutes(minutes_max_count), minutes_max);
  }

  // Minutes (might, depending on the platform) saturate at -inf.
  const auto chrono_minutes_min = std::chrono::minutes::min();
  const auto minutes_min = absl::FromChrono(chrono_minutes_min);
  const int64_t minutes_min_count = chrono_minutes_min.count();
  if (minutes_min_count < kint64min / 60) {
    EXPECT_EQ(-absl::InfiniteDuration(), minutes_min);
  } else {
    EXPECT_EQ(absl::Minutes(minutes_min_count), minutes_min);
  }

  // Hours (might, depending on the platform) saturate at +inf.
  const auto chrono_hours_max = std::chrono::hours::max();
  const auto hours_max = absl::FromChrono(chrono_hours_max);
  const int64_t hours_max_count = chrono_hours_max.count();
  if (hours_max_count > kint64max / 3600) {
    EXPECT_EQ(absl::InfiniteDuration(), hours_max);
  } else {
    EXPECT_EQ(absl::Hours(hours_max_count), hours_max);
  }

  // Hours (might, depending on the platform) saturate at -inf.
  const auto chrono_hours_min = std::chrono::hours::min();
  const auto hours_min = absl::FromChrono(chrono_hours_min);
  const int64_t hours_min_count = chrono_hours_min.count();
  if (hours_min_count < kint64min / 3600) {
    EXPECT_EQ(-absl::InfiniteDuration(), hours_min);
  } else {
    EXPECT_EQ(absl::Hours(hours_min_count), hours_min);
  }
}

template <int64_t N>
void TestToChrono() {
  using std::chrono::nanoseconds;
  using std::chrono::microseconds;
  using std::chrono::milliseconds;
  using std::chrono::seconds;
  using std::chrono::minutes;
  using std::chrono::hours;

  EXPECT_EQ(nanoseconds(N), absl::ToChronoNanoseconds(absl::Nanoseconds(N)));
  EXPECT_EQ(microseconds(N), absl::ToChronoMicroseconds(absl::Microseconds(N)));
  EXPECT_EQ(milliseconds(N), absl::ToChronoMilliseconds(absl::Milliseconds(N)));
  EXPECT_EQ(seconds(N), absl::ToChronoSeconds(absl::Seconds(N)));

  constexpr auto absl_minutes = absl::Minutes(N);
  auto chrono_minutes = minutes(N);
  if (absl_minutes == -absl::InfiniteDuration()) {
    chrono_minutes = minutes::min();
  } else if (absl_minutes == absl::InfiniteDuration()) {
    chrono_minutes = minutes::max();
  }
  EXPECT_EQ(chrono_minutes, absl::ToChronoMinutes(absl_minutes));

  constexpr auto absl_hours = absl::Hours(N);
  auto chrono_hours = hours(N);
  if (absl_hours == -absl::InfiniteDuration()) {
    chrono_hours = hours::min();
  } else if (absl_hours == absl::InfiniteDuration()) {
    chrono_hours = hours::max();
  }
  EXPECT_EQ(chrono_hours, absl::ToChronoHours(absl_hours));
}

TEST(Duration, ToChrono) {
  using std::chrono::nanoseconds;
  using std::chrono::microseconds;
  using std::chrono::milliseconds;
  using std::chrono::seconds;
  using std::chrono::minutes;
  using std::chrono::hours;

  TestToChrono<kint64min>();
  TestToChrono<-1>();
  TestToChrono<0>();
  TestToChrono<1>();
  TestToChrono<kint64max>();

  // Verify truncation toward zero.
  const auto tick = absl::Nanoseconds(1) / 4;
  EXPECT_EQ(nanoseconds(0), absl::ToChronoNanoseconds(tick));
  EXPECT_EQ(nanoseconds(0), absl::ToChronoNanoseconds(-tick));
  EXPECT_EQ(microseconds(0), absl::ToChronoMicroseconds(tick));
  EXPECT_EQ(microseconds(0), absl::ToChronoMicroseconds(-tick));
  EXPECT_EQ(milliseconds(0), absl::ToChronoMilliseconds(tick));
  EXPECT_EQ(milliseconds(0), absl::ToChronoMilliseconds(-tick));
  EXPECT_EQ(seconds(0), absl::ToChronoSeconds(tick));
  EXPECT_EQ(seconds(0), absl::ToChronoSeconds(-tick));
  EXPECT_EQ(minutes(0), absl::ToChronoMinutes(tick));
  EXPECT_EQ(minutes(0), absl::ToChronoMinutes(-tick));
  EXPECT_EQ(hours(0), absl::ToChronoHours(tick));
  EXPECT_EQ(hours(0), absl::ToChronoHours(-tick));

  // Verifies +/- infinity saturation at max/min.
  constexpr auto inf = absl::InfiniteDuration();
  EXPECT_EQ(nanoseconds::min(), absl::ToChronoNanoseconds(-inf));
  EXPECT_EQ(nanoseconds::max(), absl::ToChronoNanoseconds(inf));
  EXPECT_EQ(microseconds::min(), absl::ToChronoMicroseconds(-inf));
  EXPECT_EQ(microseconds::max(), absl::ToChronoMicroseconds(inf));
  EXPECT_EQ(milliseconds::min(), absl::ToChronoMilliseconds(-inf));
  EXPECT_EQ(milliseconds::max(), absl::ToChronoMilliseconds(inf));
  EXPECT_EQ(seconds::min(), absl::ToChronoSeconds(-inf));
  EXPECT_EQ(seconds::max(), absl::ToChronoSeconds(inf));
  EXPECT_EQ(minutes::min(), absl::ToChronoMinutes(-inf));
  EXPECT_EQ(minutes::max(), absl::ToChronoMinutes(inf));
  EXPECT_EQ(hours::min(), absl::ToChronoHours(-inf));
  EXPECT_EQ(hours::max(), absl::ToChronoHours(inf));
}

TEST(Duration, FactoryOverloads) {
  enum E { kOne = 1 };
#define TEST_FACTORY_OVERLOADS(NAME)                                          \
  EXPECT_EQ(1, NAME(kOne) / NAME(kOne));                                      \
  EXPECT_EQ(1, NAME(static_cast<int8_t>(1)) / NAME(1));                       \
  EXPECT_EQ(1, NAME(static_cast<int16_t>(1)) / NAME(1));                      \
  EXPECT_EQ(1, NAME(static_cast<int32_t>(1)) / NAME(1));                      \
  EXPECT_EQ(1, NAME(static_cast<int64_t>(1)) / NAME(1));                      \
  EXPECT_EQ(1, NAME(static_cast<uint8_t>(1)) / NAME(1));                      \
  EXPECT_EQ(1, NAME(static_cast<uint16_t>(1)) / NAME(1));                     \
  EXPECT_EQ(1, NAME(static_cast<uint32_t>(1)) / NAME(1));                     \
  EXPECT_EQ(1, NAME(static_cast<uint64_t>(1)) / NAME(1));                     \
  EXPECT_EQ(NAME(1) / 2, NAME(static_cast<float>(0.5)));                      \
  EXPECT_EQ(NAME(1) / 2, NAME(static_cast<double>(0.5)));                     \
  EXPECT_EQ(1.5, absl::FDivDuration(NAME(static_cast<float>(1.5)), NAME(1))); \
  EXPECT_EQ(1.5, absl::FDivDuration(NAME(static_cast<double>(1.5)), NAME(1)));

  TEST_FACTORY_OVERLOADS(absl::Nanoseconds);
  TEST_FACTORY_OVERLOADS(absl::Microseconds);
  TEST_FACTORY_OVERLOADS(absl::Milliseconds);
  TEST_FACTORY_OVERLOADS(absl::Seconds);
  TEST_FACTORY_OVERLOADS(absl::Minutes);
  TEST_FACTORY_OVERLOADS(absl::Hours);

#undef TEST_FACTORY_OVERLOADS

  EXPECT_EQ(absl::Milliseconds(1500), absl::Seconds(1.5));
  EXPECT_LT(absl::Nanoseconds(1), absl::Nanoseconds(1.5));
  EXPECT_GT(absl::Nanoseconds(2), absl::Nanoseconds(1.5));

  const double dbl_inf = std::numeric_limits<double>::infinity();
  EXPECT_EQ(absl::InfiniteDuration(), absl::Nanoseconds(dbl_inf));
  EXPECT_EQ(absl::InfiniteDuration(), absl::Microseconds(dbl_inf));
  EXPECT_EQ(absl::InfiniteDuration(), absl::Milliseconds(dbl_inf));
  EXPECT_EQ(absl::InfiniteDuration(), absl::Seconds(dbl_inf));
  EXPECT_EQ(absl::InfiniteDuration(), absl::Minutes(dbl_inf));
  EXPECT_EQ(absl::InfiniteDuration(), absl::Hours(dbl_inf));
  EXPECT_EQ(-absl::InfiniteDuration(), absl::Nanoseconds(-dbl_inf));
  EXPECT_EQ(-absl::InfiniteDuration(), absl::Microseconds(-dbl_inf));
  EXPECT_EQ(-absl::InfiniteDuration(), absl::Milliseconds(-dbl_inf));
  EXPECT_EQ(-absl::InfiniteDuration(), absl::Seconds(-dbl_inf));
  EXPECT_EQ(-absl::InfiniteDuration(), absl::Minutes(-dbl_inf));
  EXPECT_EQ(-absl::InfiniteDuration(), absl::Hours(-dbl_inf));
}

TEST(Duration, InfinityExamples) {
  // These examples are used in the documentation in time.h. They are
  // written so that they can be copy-n-pasted easily.

  constexpr absl::Duration inf = absl::InfiniteDuration();
  constexpr absl::Duration d = absl::Seconds(1);  // Any finite duration

  EXPECT_TRUE(inf == inf + inf);
  EXPECT_TRUE(inf == inf + d);
  EXPECT_TRUE(inf == inf - inf);
  EXPECT_TRUE(-inf == d - inf);

  EXPECT_TRUE(inf == d * 1e100);
  EXPECT_TRUE(0 == d / inf);  // NOLINT(readability/check)

  // Division by zero returns infinity, or kint64min/MAX where necessary.
  EXPECT_TRUE(inf == d / 0);
  EXPECT_TRUE(kint64max == d / absl::ZeroDuration());
}

TEST(Duration, InfinityComparison) {
  const absl::Duration inf = absl::InfiniteDuration();
  const absl::Duration any_dur = absl::Seconds(1);

  // Equality
  EXPECT_EQ(inf, inf);
  EXPECT_EQ(-inf, -inf);
  EXPECT_NE(inf, -inf);
  EXPECT_NE(any_dur, inf);
  EXPECT_NE(any_dur, -inf);

  // Relational
  EXPECT_GT(inf, any_dur);
  EXPECT_LT(-inf, any_dur);
  EXPECT_LT(-inf, inf);
  EXPECT_GT(inf, -inf);
}

TEST(Duration, InfinityAddition) {
  const absl::Duration sec_max = absl::Seconds(kint64max);
  const absl::Duration sec_min = absl::Seconds(kint64min);
  const absl::Duration any_dur = absl::Seconds(1);
  const absl::Duration inf = absl::InfiniteDuration();

  // Addition
  EXPECT_EQ(inf, inf + inf);
  EXPECT_EQ(inf, inf + -inf);
  EXPECT_EQ(-inf, -inf + inf);
  EXPECT_EQ(-inf, -inf + -inf);

  EXPECT_EQ(inf, inf + any_dur);
  EXPECT_EQ(inf, any_dur + inf);
  EXPECT_EQ(-inf, -inf + any_dur);
  EXPECT_EQ(-inf, any_dur + -inf);

  // Interesting case
  absl::Duration almost_inf = sec_max + absl::Nanoseconds(999999999);
  EXPECT_GT(inf, almost_inf);
  almost_inf += -absl::Nanoseconds(999999999);
  EXPECT_GT(inf, almost_inf);

  // Addition overflow/underflow
  EXPECT_EQ(inf, sec_max + absl::Seconds(1));
  EXPECT_EQ(inf, sec_max + sec_max);
  EXPECT_EQ(-inf, sec_min + -absl::Seconds(1));
  EXPECT_EQ(-inf, sec_min + -sec_max);

  // For reference: IEEE 754 behavior
  const double dbl_inf = std::numeric_limits<double>::infinity();
  EXPECT_TRUE(std::isinf(dbl_inf + dbl_inf));
  EXPECT_TRUE(std::isnan(dbl_inf + -dbl_inf));  // We return inf
  EXPECT_TRUE(std::isnan(-dbl_inf + dbl_inf));  // We return inf
  EXPECT_TRUE(std::isinf(-dbl_inf + -dbl_inf));
}

TEST(Duration, InfinitySubtraction) {
  const absl::Duration sec_max = absl::Seconds(kint64max);
  const absl::Duration sec_min = absl::Seconds(kint64min);
  const absl::Duration any_dur = absl::Seconds(1);
  const absl::Duration inf = absl::InfiniteDuration();

  // Subtraction
  EXPECT_EQ(inf, inf - inf);
  EXPECT_EQ(inf, inf - -inf);
  EXPECT_EQ(-inf, -inf - inf);
  EXPECT_EQ(-inf, -inf - -inf);

  EXPECT_EQ(inf, inf - any_dur);
  EXPECT_EQ(-inf, any_dur - inf);
  EXPECT_EQ(-inf, -inf - any_dur);
  EXPECT_EQ(inf, any_dur - -inf);

  // Subtraction overflow/underflow
  EXPECT_EQ(inf, sec_max - -absl::Seconds(1));
  EXPECT_EQ(inf, sec_max - -sec_max);
  EXPECT_EQ(-inf, sec_min - absl::Seconds(1));
  EXPECT_EQ(-inf, sec_min - sec_max);

  // Interesting case
  absl::Duration almost_neg_inf = sec_min;
  EXPECT_LT(-inf, almost_neg_inf);
  almost_neg_inf -= -absl::Nanoseconds(1);
  EXPECT_LT(-inf, almost_neg_inf);

  // For reference: IEEE 754 behavior
  const double dbl_inf = std::numeric_limits<double>::infinity();
  EXPECT_TRUE(std::isnan(dbl_inf - dbl_inf));  // We return inf
  EXPECT_TRUE(std::isinf(dbl_inf - -dbl_inf));
  EXPECT_TRUE(std::isinf(-dbl_inf - dbl_inf));
  EXPECT_TRUE(std::isnan(-dbl_inf - -dbl_inf));  // We return inf
}

TEST(Duration, InfinityMultiplication) {
  const absl::Duration sec_max = absl::Seconds(kint64max);
  const absl::Duration sec_min = absl::Seconds(kint64min);
  const absl::Duration inf = absl::InfiniteDuration();

#define TEST_INF_MUL_WITH_TYPE(T)                                     \
  EXPECT_EQ(inf, inf * static_cast<T>(2));                            \
  EXPECT_EQ(-inf, inf * static_cast<T>(-2));                          \
  EXPECT_EQ(-inf, -inf * static_cast<T>(2));                          \
  EXPECT_EQ(inf, -inf * static_cast<T>(-2));                          \
  EXPECT_EQ(inf, inf * static_cast<T>(0));                            \
  EXPECT_EQ(-inf, -inf * static_cast<T>(0));                          \
  EXPECT_EQ(inf, sec_max * static_cast<T>(2));                        \
  EXPECT_EQ(inf, sec_min * static_cast<T>(-2));                       \
  EXPECT_EQ(inf, (sec_max / static_cast<T>(2)) * static_cast<T>(3));  \
  EXPECT_EQ(-inf, sec_max * static_cast<T>(-2));                      \
  EXPECT_EQ(-inf, sec_min * static_cast<T>(2));                       \
  EXPECT_EQ(-inf, (sec_min / static_cast<T>(2)) * static_cast<T>(3));

  TEST_INF_MUL_WITH_TYPE(int64_t);  // NOLINT(readability/function)
  TEST_INF_MUL_WITH_TYPE(double);   // NOLINT(readability/function)

#undef TEST_INF_MUL_WITH_TYPE

  const double dbl_inf = std::numeric_limits<double>::infinity();
  EXPECT_EQ(inf, inf * dbl_inf);
  EXPECT_EQ(-inf, -inf * dbl_inf);
  EXPECT_EQ(-inf, inf * -dbl_inf);
  EXPECT_EQ(inf, -inf * -dbl_inf);

  const absl::Duration any_dur = absl::Seconds(1);
  EXPECT_EQ(inf, any_dur * dbl_inf);
  EXPECT_EQ(-inf, -any_dur * dbl_inf);
  EXPECT_EQ(-inf, any_dur * -dbl_inf);
  EXPECT_EQ(inf, -any_dur * -dbl_inf);

  // Fixed-point multiplication will produce a finite value, whereas floating
  // point fuzziness will overflow to inf.
  EXPECT_NE(absl::InfiniteDuration(), absl::Seconds(1) * kint64max);
  EXPECT_EQ(inf, absl::Seconds(1) * static_cast<double>(kint64max));
  EXPECT_NE(-absl::InfiniteDuration(), absl::Seconds(1) * kint64min);
  EXPECT_EQ(-inf, absl::Seconds(1) * static_cast<double>(kint64min));

  // Note that sec_max * or / by 1.0 overflows to inf due to the 53-bit
  // limitations of double.
  EXPECT_NE(inf, sec_max);
  EXPECT_NE(inf, sec_max / 1);
  EXPECT_EQ(inf, sec_max / 1.0);
  EXPECT_NE(inf, sec_max * 1);
  EXPECT_EQ(inf, sec_max * 1.0);
}

TEST(Duration, InfinityDivision) {
  const absl::Duration sec_max = absl::Seconds(kint64max);
  const absl::Duration sec_min = absl::Seconds(kint64min);
  const absl::Duration inf = absl::InfiniteDuration();

  // Division of Duration by a double
#define TEST_INF_DIV_WITH_TYPE(T)            \
  EXPECT_EQ(inf, inf / static_cast<T>(2));   \
  EXPECT_EQ(-inf, inf / static_cast<T>(-2)); \
  EXPECT_EQ(-inf, -inf / static_cast<T>(2)); \
  EXPECT_EQ(inf, -inf / static_cast<T>(-2));

  TEST_INF_DIV_WITH_TYPE(int64_t);  // NOLINT(readability/function)
  TEST_INF_DIV_WITH_TYPE(double);   // NOLINT(readability/function)

#undef TEST_INF_DIV_WITH_TYPE

  // Division of Duration by a double overflow/underflow
  EXPECT_EQ(inf, sec_max / 0.5);
  EXPECT_EQ(inf, sec_min / -0.5);
  EXPECT_EQ(inf, ((sec_max / 0.5) + absl::Seconds(1)) / 0.5);
  EXPECT_EQ(-inf, sec_max / -0.5);
  EXPECT_EQ(-inf, sec_min / 0.5);
  EXPECT_EQ(-inf, ((sec_min / 0.5) - absl::Seconds(1)) / 0.5);

  const double dbl_inf = std::numeric_limits<double>::infinity();
  EXPECT_EQ(inf, inf / dbl_inf);
  EXPECT_EQ(-inf, inf / -dbl_inf);
  EXPECT_EQ(-inf, -inf / dbl_inf);
  EXPECT_EQ(inf, -inf / -dbl_inf);

  const absl::Duration any_dur = absl::Seconds(1);
  EXPECT_EQ(absl::ZeroDuration(), any_dur / dbl_inf);
  EXPECT_EQ(absl::ZeroDuration(), any_dur / -dbl_inf);
  EXPECT_EQ(absl::ZeroDuration(), -any_dur / dbl_inf);
  EXPECT_EQ(absl::ZeroDuration(), -any_dur / -dbl_inf);
}

TEST(Duration, InfinityModulus) {
  const absl::Duration sec_max = absl::Seconds(kint64max);
  const absl::Duration any_dur = absl::Seconds(1);
  const absl::Duration inf = absl::InfiniteDuration();

  EXPECT_EQ(inf, inf % inf);
  EXPECT_EQ(inf, inf % -inf);
  EXPECT_EQ(-inf, -inf % -inf);
  EXPECT_EQ(-inf, -inf % inf);

  EXPECT_EQ(any_dur, any_dur % inf);
  EXPECT_EQ(any_dur, any_dur % -inf);
  EXPECT_EQ(-any_dur, -any_dur % inf);
  EXPECT_EQ(-any_dur, -any_dur % -inf);

  EXPECT_EQ(inf, inf % -any_dur);
  EXPECT_EQ(inf, inf % any_dur);
  EXPECT_EQ(-inf, -inf % -any_dur);
  EXPECT_EQ(-inf, -inf % any_dur);

  // Remainder isn't affected by overflow.
  EXPECT_EQ(absl::ZeroDuration(), sec_max % absl::Seconds(1));
  EXPECT_EQ(absl::ZeroDuration(), sec_max % absl::Milliseconds(1));
  EXPECT_EQ(absl::ZeroDuration(), sec_max % absl::Microseconds(1));
  EXPECT_EQ(absl::ZeroDuration(), sec_max % absl::Nanoseconds(1));
  EXPECT_EQ(absl::ZeroDuration(), sec_max % absl::Nanoseconds(1) / 4);
}

TEST(Duration, InfinityIDiv) {
  const absl::Duration sec_max = absl::Seconds(kint64max);
  const absl::Duration any_dur = absl::Seconds(1);
  const absl::Duration inf = absl::InfiniteDuration();
  const double dbl_inf = std::numeric_limits<double>::infinity();

  // IDivDuration (int64_t return value + a remainer)
  absl::Duration rem = absl::ZeroDuration();
  EXPECT_EQ(kint64max, absl::IDivDuration(inf, inf, &rem));
  EXPECT_EQ(inf, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(kint64max, absl::IDivDuration(-inf, -inf, &rem));
  EXPECT_EQ(-inf, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(kint64max, absl::IDivDuration(inf, any_dur, &rem));
  EXPECT_EQ(inf, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(0, absl::IDivDuration(any_dur, inf, &rem));
  EXPECT_EQ(any_dur, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(kint64max, absl::IDivDuration(-inf, -any_dur, &rem));
  EXPECT_EQ(-inf, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(0, absl::IDivDuration(-any_dur, -inf, &rem));
  EXPECT_EQ(-any_dur, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(kint64min, absl::IDivDuration(-inf, inf, &rem));
  EXPECT_EQ(-inf, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(kint64min, absl::IDivDuration(inf, -inf, &rem));
  EXPECT_EQ(inf, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(kint64min, absl::IDivDuration(-inf, any_dur, &rem));
  EXPECT_EQ(-inf, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(0, absl::IDivDuration(-any_dur, inf, &rem));
  EXPECT_EQ(-any_dur, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(kint64min, absl::IDivDuration(inf, -any_dur, &rem));
  EXPECT_EQ(inf, rem);

  rem = absl::ZeroDuration();
  EXPECT_EQ(0, absl::IDivDuration(any_dur, -inf, &rem));
  EXPECT_EQ(any_dur, rem);

  // IDivDuration overflow/underflow
  rem = any_dur;
  EXPECT_EQ(kint64max,
            absl::IDivDuration(sec_max, absl::Nanoseconds(1) / 4, &rem));
  EXPECT_EQ(sec_max - absl::Nanoseconds(kint64max) / 4, rem);

  rem = any_dur;
  EXPECT_EQ(kint64max,
            absl::IDivDuration(sec_max, absl::Milliseconds(1), &rem));
  EXPECT_EQ(sec_max - absl::Milliseconds(kint64max), rem);

  rem = any_dur;
  EXPECT_EQ(kint64max,
            absl::IDivDuration(-sec_max, -absl::Milliseconds(1), &rem));
  EXPECT_EQ(-sec_max + absl::Milliseconds(kint64max), rem);

  rem = any_dur;
  EXPECT_EQ(kint64min,
            absl::IDivDuration(-sec_max, absl::Milliseconds(1), &rem));
  EXPECT_EQ(-sec_max - absl::Milliseconds(kint64min), rem);

  rem = any_dur;
  EXPECT_EQ(kint64min,
            absl::IDivDuration(sec_max, -absl::Milliseconds(1), &rem));
  EXPECT_EQ(sec_max + absl::Milliseconds(kint64min), rem);

  //
  // operator/(Duration, Duration) is a wrapper for IDivDuration().
  //

  // IEEE 754 says inf / inf should be nan, but int64_t doesn't have
  // nan so we'll return kint64max/kint64min instead.
  EXPECT_TRUE(std::isnan(dbl_inf / dbl_inf));
  EXPECT_EQ(kint64max, inf / inf);
  EXPECT_EQ(kint64max, -inf / -inf);
  EXPECT_EQ(kint64min, -inf / inf);
  EXPECT_EQ(kint64min, inf / -inf);

  EXPECT_TRUE(std::isinf(dbl_inf / 2.0));
  EXPECT_EQ(kint64max, inf / any_dur);
  EXPECT_EQ(kint64max, -inf / -any_dur);
  EXPECT_EQ(kint64min, -inf / any_dur);
  EXPECT_EQ(kint64min, inf / -any_dur);

  EXPECT_EQ(0.0, 2.0 / dbl_inf);
  EXPECT_EQ(0, any_dur / inf);
  EXPECT_EQ(0, any_dur / -inf);
  EXPECT_EQ(0, -any_dur / inf);
  EXPECT_EQ(0, -any_dur / -inf);
  EXPECT_EQ(0, absl::ZeroDuration() / inf);

  // Division of Duration by a Duration overflow/underflow
  EXPECT_EQ(kint64max, sec_max / absl::Milliseconds(1));
  EXPECT_EQ(kint64max, -sec_max / -absl::Milliseconds(1));
  EXPECT_EQ(kint64min, -sec_max / absl::Milliseconds(1));
  EXPECT_EQ(kint64min, sec_max / -absl::Milliseconds(1));
}

TEST(Duration, InfinityFDiv) {
  const absl::Duration any_dur = absl::Seconds(1);
  const absl::Duration inf = absl::InfiniteDuration();
  const double dbl_inf = std::numeric_limits<double>::infinity();

  EXPECT_EQ(dbl_inf, absl::FDivDuration(inf, inf));
  EXPECT_EQ(dbl_inf, absl::FDivDuration(-inf, -inf));
  EXPECT_EQ(dbl_inf, absl::FDivDuration(inf, any_dur));
  EXPECT_EQ(0.0, absl::FDivDuration(any_dur, inf));
  EXPECT_EQ(dbl_inf, absl::FDivDuration(-inf, -any_dur));
  EXPECT_EQ(0.0, absl::FDivDuration(-any_dur, -inf));

  EXPECT_EQ(-dbl_inf, absl::FDivDuration(-inf, inf));
  EXPECT_EQ(-dbl_inf, absl::FDivDuration(inf, -inf));
  EXPECT_EQ(-dbl_inf, absl::FDivDuration(-inf, any_dur));
  EXPECT_EQ(0.0, absl::FDivDuration(-any_dur, inf));
  EXPECT_EQ(-dbl_inf, absl::FDivDuration(inf, -any_dur));
  EXPECT_EQ(0.0, absl::FDivDuration(any_dur, -inf));
}

TEST(Duration, DivisionByZero) {
  const absl::Duration zero = absl::ZeroDuration();
  const absl::Duration inf = absl::InfiniteDuration();
  const absl::Duration any_dur = absl::Seconds(1);
  const double dbl_inf = std::numeric_limits<double>::infinity();
  const double dbl_denorm = std::numeric_limits<double>::denorm_min();

  // IEEE 754 behavior
  double z = 0.0, two = 2.0;
  EXPECT_TRUE(std::isinf(two / z));
  EXPECT_TRUE(std::isnan(z / z));  // We'll return inf

  // Operator/(Duration, double)
  EXPECT_EQ(inf, zero / 0.0);
  EXPECT_EQ(-inf, zero / -0.0);
  EXPECT_EQ(inf, any_dur / 0.0);
  EXPECT_EQ(-inf, any_dur / -0.0);
  EXPECT_EQ(-inf, -any_dur / 0.0);
  EXPECT_EQ(inf, -any_dur / -0.0);

  // Tests dividing by a number very close to, but not quite zero.
  EXPECT_EQ(zero, zero / dbl_denorm);
  EXPECT_EQ(zero, zero / -dbl_denorm);
  EXPECT_EQ(inf, any_dur / dbl_denorm);
  EXPECT_EQ(-inf, any_dur / -dbl_denorm);
  EXPECT_EQ(-inf, -any_dur / dbl_denorm);
  EXPECT_EQ(inf, -any_dur / -dbl_denorm);

  // IDiv
  absl::Duration rem = zero;
  EXPECT_EQ(kint64max, absl::IDivDuration(zero, zero, &rem));
  EXPECT_EQ(inf, rem);

  rem = zero;
  EXPECT_EQ(kint64max, absl::IDivDuration(any_dur, zero, &rem));
  EXPECT_EQ(inf, rem);

  rem = zero;
  EXPECT_EQ(kint64min, absl::IDivDuration(-any_dur, zero, &rem));
  EXPECT_EQ(-inf, rem);

  // Operator/(Duration, Duration)
  EXPECT_EQ(kint64max, zero / zero);
  EXPECT_EQ(kint64max, any_dur / zero);
  EXPECT_EQ(kint64min, -any_dur / zero);

  // FDiv
  EXPECT_EQ(dbl_inf, absl::FDivDuration(zero, zero));
  EXPECT_EQ(dbl_inf, absl::FDivDuration(any_dur, zero));
  EXPECT_EQ(-dbl_inf, absl::FDivDuration(-any_dur, zero));
}

TEST(Duration, Range) {
  const absl::Duration range = ApproxYears(100 * 1e9);
  const absl::Duration range_future = range;
  const absl::Duration range_past = -range;

  EXPECT_LT(range_future, absl::InfiniteDuration());
  EXPECT_GT(range_past, -absl::InfiniteDuration());

  const absl::Duration full_range = range_future - range_past;
  EXPECT_GT(full_range, absl::ZeroDuration());
  EXPECT_LT(full_range, absl::InfiniteDuration());

  const absl::Duration neg_full_range = range_past - range_future;
  EXPECT_LT(neg_full_range, absl::ZeroDuration());
  EXPECT_GT(neg_full_range, -absl::InfiniteDuration());

  EXPECT_LT(neg_full_range, full_range);
  EXPECT_EQ(neg_full_range, -full_range);
}

TEST(Duration, RelationalOperators) {
#define TEST_REL_OPS(UNIT)               \
  static_assert(UNIT(2) == UNIT(2), ""); \
  static_assert(UNIT(1) != UNIT(2), ""); \
  static_assert(UNIT(1) < UNIT(2), "");  \
  static_assert(UNIT(3) > UNIT(2), "");  \
  static_assert(UNIT(1) <= UNIT(2), ""); \
  static_assert(UNIT(2) <= UNIT(2), ""); \
  static_assert(UNIT(3) >= UNIT(2), ""); \
  static_assert(UNIT(2) >= UNIT(2), "");

  TEST_REL_OPS(absl::Nanoseconds);
  TEST_REL_OPS(absl::Microseconds);
  TEST_REL_OPS(absl::Milliseconds);
  TEST_REL_OPS(absl::Seconds);
  TEST_REL_OPS(absl::Minutes);
  TEST_REL_OPS(absl::Hours);

#undef TEST_REL_OPS
}

TEST(Duration, Addition) {
#define TEST_ADD_OPS(UNIT)                  \
  do {                                      \
    EXPECT_EQ(UNIT(2), UNIT(1) + UNIT(1));  \
    EXPECT_EQ(UNIT(1), UNIT(2) - UNIT(1));  \
    EXPECT_EQ(UNIT(0), UNIT(2) - UNIT(2));  \
    EXPECT_EQ(UNIT(-1), UNIT(1) - UNIT(2)); \
    EXPECT_EQ(UNIT(-2), UNIT(0) - UNIT(2)); \
    EXPECT_EQ(UNIT(-2), UNIT(1) - UNIT(3)); \
    absl::Duration a = UNIT(1);             \
    a += UNIT(1);                           \
    EXPECT_EQ(UNIT(2), a);                  \
    a -= UNIT(1);                           \
    EXPECT_EQ(UNIT(1), a);                  \
  } while (0)

  TEST_ADD_OPS(absl::Nanoseconds);
  TEST_ADD_OPS(absl::Microseconds);
  TEST_ADD_OPS(absl::Milliseconds);
  TEST_ADD_OPS(absl::Seconds);
  TEST_ADD_OPS(absl::Minutes);
  TEST_ADD_OPS(absl::Hours);

#undef TEST_ADD_OPS

  EXPECT_EQ(absl::Seconds(2), absl::Seconds(3) - 2 * absl::Milliseconds(500));
  EXPECT_EQ(absl::Seconds(2) + absl::Milliseconds(500),
            absl::Seconds(3) - absl::Milliseconds(500));

  EXPECT_EQ(absl::Seconds(1) + absl::Milliseconds(998),
            absl::Milliseconds(999) + absl::Milliseconds(999));

  EXPECT_EQ(absl::Milliseconds(-1),
            absl::Milliseconds(998) - absl::Milliseconds(999));

  // Tests fractions of a nanoseconds. These are implementation details only.
  EXPECT_GT(absl::Nanoseconds(1), absl::Nanoseconds(1) / 2);
  EXPECT_EQ(absl::Nanoseconds(1),
            absl::Nanoseconds(1) / 2 + absl::Nanoseconds(1) / 2);
  EXPECT_GT(absl::Nanoseconds(1) / 4, absl::Nanoseconds(0));
  EXPECT_EQ(absl::Nanoseconds(1) / 8, absl::Nanoseconds(0));

  // Tests subtraction that will cause wrap around of the rep_lo_ bits.
  absl::Duration d_7_5 = absl::Seconds(7) + absl::Milliseconds(500);
  absl::Duration d_3_7 = absl::Seconds(3) + absl::Milliseconds(700);
  absl::Duration ans_3_8 = absl::Seconds(3) + absl::Milliseconds(800);
  EXPECT_EQ(ans_3_8, d_7_5 - d_3_7);

  // Subtracting min_duration
  absl::Duration min_dur = absl::Seconds(kint64min);
  EXPECT_EQ(absl::Seconds(0), min_dur - min_dur);
  EXPECT_EQ(absl::Seconds(kint64max), absl::Seconds(-1) - min_dur);
}

TEST(Duration, Negation) {
  // By storing negations of various values in constexpr variables we
  // verify that the initializers are constant expressions.
  constexpr absl::Duration negated_zero_duration = -absl::ZeroDuration();
  EXPECT_EQ(negated_zero_duration, absl::ZeroDuration());

  constexpr absl::Duration negated_infinite_duration =
      -absl::InfiniteDuration();
  EXPECT_NE(negated_infinite_duration, absl::InfiniteDuration());
  EXPECT_EQ(-negated_infinite_duration, absl::InfiniteDuration());

  // The public APIs to check if a duration is infinite depend on using
  // -InfiniteDuration(), but we're trying to test operator- here, so we
  // need to use the lower-level internal query IsInfiniteDuration.
  EXPECT_TRUE(
      absl::time_internal::IsInfiniteDuration(negated_infinite_duration));

  // The largest Duration is kint64max seconds and kTicksPerSecond - 1 ticks.
  // Using the absl::time_internal::MakeDuration API is the cleanest way to
  // construct that Duration.
  constexpr absl::Duration max_duration = absl::time_internal::MakeDuration(
      kint64max, absl::time_internal::kTicksPerSecond - 1);
  constexpr absl::Duration negated_max_duration = -max_duration;
  // The largest negatable value is one tick above the minimum representable;
  // it's the negation of max_duration.
  constexpr absl::Duration nearly_min_duration =
      absl::time_internal::MakeDuration(kint64min, int64_t{1});
  constexpr absl::Duration negated_nearly_min_duration = -nearly_min_duration;

  EXPECT_EQ(negated_max_duration, nearly_min_duration);
  EXPECT_EQ(negated_nearly_min_duration, max_duration);
  EXPECT_EQ(-(-max_duration), max_duration);

  constexpr absl::Duration min_duration =
      absl::time_internal::MakeDuration(kint64min);
  constexpr absl::Duration negated_min_duration = -min_duration;
  EXPECT_EQ(negated_min_duration, absl::InfiniteDuration());
}

TEST(Duration, AbsoluteValue) {
  EXPECT_EQ(absl::ZeroDuration(), AbsDuration(absl::ZeroDuration()));
  EXPECT_EQ(absl::Seconds(1), AbsDuration(absl::Seconds(1)));
  EXPECT_EQ(absl::Seconds(1), AbsDuration(absl::Seconds(-1)));

  EXPECT_EQ(absl::InfiniteDuration(), AbsDuration(absl::InfiniteDuration()));
  EXPECT_EQ(absl::InfiniteDuration(), AbsDuration(-absl::InfiniteDuration()));

  absl::Duration max_dur =
      absl::Seconds(kint64max) + (absl::Seconds(1) - absl::Nanoseconds(1) / 4);
  EXPECT_EQ(max_dur, AbsDuration(max_dur));

  absl::Duration min_dur = absl::Seconds(kint64min);
  EXPECT_EQ(absl::InfiniteDuration(), AbsDuration(min_dur));
  EXPECT_EQ(max_dur, AbsDuration(min_dur + absl::Nanoseconds(1) / 4));
}

TEST(Duration, Multiplication) {
#define TEST_MUL_OPS(UNIT)                                    \
  do {                                                        \
    EXPECT_EQ(UNIT(5), UNIT(2) * 2.5);                        \
    EXPECT_EQ(UNIT(2), UNIT(5) / 2.5);                        \
    EXPECT_EQ(UNIT(-5), UNIT(-2) * 2.5);                      \
    EXPECT_EQ(UNIT(-5), -UNIT(2) * 2.5);                      \
    EXPECT_EQ(UNIT(-5), UNIT(2) * -2.5);                      \
    EXPECT_EQ(UNIT(-2), UNIT(-5) / 2.5);                      \
    EXPECT_EQ(UNIT(-2), -UNIT(5) / 2.5);                      \
    EXPECT_EQ(UNIT(-2), UNIT(5) / -2.5);                      \
    EXPECT_EQ(UNIT(2), UNIT(11) % UNIT(3));                   \
    absl::Duration a = UNIT(2);                               \
    a *= 2.5;                                                 \
    EXPECT_EQ(UNIT(5), a);                                    \
    a /= 2.5;                                                 \
    EXPECT_EQ(UNIT(2), a);                                    \
    a %= UNIT(1);                                             \
    EXPECT_EQ(UNIT(0), a);                                    \
    absl::Duration big = UNIT(1000000000);                    \
    big *= 3;                                                 \
    big /= 3;                                                 \
    EXPECT_EQ(UNIT(1000000000), big);                         \
    EXPECT_EQ(-UNIT(2), -UNIT(2));                            \
    EXPECT_EQ(-UNIT(2), UNIT(2) * -1);                        \
    EXPECT_EQ(-UNIT(2), -1 * UNIT(2));                        \
    EXPECT_EQ(-UNIT(-2), UNIT(2));                            \
    EXPECT_EQ(2, UNIT(2) / UNIT(1));                          \
    absl::Duration rem;                                       \
    EXPECT_EQ(2, absl::IDivDuration(UNIT(2), UNIT(1), &rem)); \
    EXPECT_EQ(2.0, absl::FDivDuration(UNIT(2), UNIT(1)));     \
  } while (0)

  TEST_MUL_OPS(absl::Nanoseconds);
  TEST_MUL_OPS(absl::Microseconds);
  TEST_MUL_OPS(absl::Milliseconds);
  TEST_MUL_OPS(absl::Seconds);
  TEST_MUL_OPS(absl::Minutes);
  TEST_MUL_OPS(absl::Hours);

#undef TEST_MUL_OPS

  // Ensures that multiplication and division by 1 with a maxed-out durations
  // doesn't lose precision.
  absl::Duration max_dur =
      absl::Seconds(kint64max) + (absl::Seconds(1) - absl::Nanoseconds(1) / 4);
  absl::Duration min_dur = absl::Seconds(kint64min);
  EXPECT_EQ(max_dur, max_dur * 1);
  EXPECT_EQ(max_dur, max_dur / 1);
  EXPECT_EQ(min_dur, min_dur * 1);
  EXPECT_EQ(min_dur, min_dur / 1);

  // Tests division on a Duration with a large number of significant digits.
  // Tests when the digits span hi and lo as well as only in hi.
  absl::Duration sigfigs = absl::Seconds(2000000000) + absl::Nanoseconds(3);
  EXPECT_EQ(absl::Seconds(666666666) + absl::Nanoseconds(666666667) +
                absl::Nanoseconds(1) / 2,
            sigfigs / 3);
  sigfigs = absl::Seconds(7000000000LL);
  EXPECT_EQ(absl::Seconds(2333333333) + absl::Nanoseconds(333333333) +
                absl::Nanoseconds(1) / 4,
            sigfigs / 3);

  EXPECT_EQ(absl::Seconds(7) + absl::Milliseconds(500), absl::Seconds(3) * 2.5);
  EXPECT_EQ(absl::Seconds(8) * -1 + absl::Milliseconds(300),
            (absl::Seconds(2) + absl::Milliseconds(200)) * -3.5);
  EXPECT_EQ(-absl::Seconds(8) + absl::Milliseconds(300),
            (absl::Seconds(2) + absl::Milliseconds(200)) * -3.5);
  EXPECT_EQ(absl::Seconds(1) + absl::Milliseconds(875),
            (absl::Seconds(7) + absl::Milliseconds(500)) / 4);
  EXPECT_EQ(absl::Seconds(30),
            (absl::Seconds(7) + absl::Milliseconds(500)) / 0.25);
  EXPECT_EQ(absl::Seconds(3),
            (absl::Seconds(7) + absl::Milliseconds(500)) / 2.5);

  // Tests division remainder.
  EXPECT_EQ(absl::Nanoseconds(0), absl::Nanoseconds(7) % absl::Nanoseconds(1));
  EXPECT_EQ(absl::Nanoseconds(0), absl::Nanoseconds(0) % absl::Nanoseconds(10));
  EXPECT_EQ(absl::Nanoseconds(2), absl::Nanoseconds(7) % absl::Nanoseconds(5));
  EXPECT_EQ(absl::Nanoseconds(2), absl::Nanoseconds(2) % absl::Nanoseconds(5));

  EXPECT_EQ(absl::Nanoseconds(1), absl::Nanoseconds(10) % absl::Nanoseconds(3));
  EXPECT_EQ(absl::Nanoseconds(1),
            absl::Nanoseconds(10) % absl::Nanoseconds(-3));
  EXPECT_EQ(absl::Nanoseconds(-1),
            absl::Nanoseconds(-10) % absl::Nanoseconds(3));
  EXPECT_EQ(absl::Nanoseconds(-1),
            absl::Nanoseconds(-10) % absl::Nanoseconds(-3));

  EXPECT_EQ(absl::Milliseconds(100),
            absl::Seconds(1) % absl::Milliseconds(300));
  EXPECT_EQ(
      absl::Milliseconds(300),
      (absl::Seconds(3) + absl::Milliseconds(800)) % absl::Milliseconds(500));

  EXPECT_EQ(absl::Nanoseconds(1), absl::Nanoseconds(1) % absl::Seconds(1));
  EXPECT_EQ(absl::Nanoseconds(-1), absl::Nanoseconds(-1) % absl::Seconds(1));
  EXPECT_EQ(0, absl::Nanoseconds(-1) / absl::Seconds(1));  // Actual -1e-9

  // Tests identity a = (a/b)*b + a%b
#define TEST_MOD_IDENTITY(a, b) \
  EXPECT_EQ((a), ((a) / (b))*(b) + ((a)%(b)))

  TEST_MOD_IDENTITY(absl::Seconds(0), absl::Seconds(2));
  TEST_MOD_IDENTITY(absl::Seconds(1), absl::Seconds(1));
  TEST_MOD_IDENTITY(absl::Seconds(1), absl::Seconds(2));
  TEST_MOD_IDENTITY(absl::Seconds(2), absl::Seconds(1));

  TEST_MOD_IDENTITY(absl::Seconds(-2), absl::Seconds(1));
  TEST_MOD_IDENTITY(absl::Seconds(2), absl::Seconds(-1));
  TEST_MOD_IDENTITY(absl::Seconds(-2), absl::Seconds(-1));

  TEST_MOD_IDENTITY(absl::Nanoseconds(0), absl::Nanoseconds(2));
  TEST_MOD_IDENTITY(absl::Nanoseconds(1), absl::Nanoseconds(1));
  TEST_MOD_IDENTITY(absl::Nanoseconds(1), absl::Nanoseconds(2));
  TEST_MOD_IDENTITY(absl::Nanoseconds(2), absl::Nanoseconds(1));

  TEST_MOD_IDENTITY(absl::Nanoseconds(-2), absl::Nanoseconds(1));
  TEST_MOD_IDENTITY(absl::Nanoseconds(2), absl::Nanoseconds(-1));
  TEST_MOD_IDENTITY(absl::Nanoseconds(-2), absl::Nanoseconds(-1));

  // Mixed seconds + subseconds
  absl::Duration mixed_a = absl::Seconds(1) + absl::Nanoseconds(2);
  absl::Duration mixed_b = absl::Seconds(1) + absl::Nanoseconds(3);

  TEST_MOD_IDENTITY(absl::Seconds(0), mixed_a);
  TEST_MOD_IDENTITY(mixed_a, mixed_a);
  TEST_MOD_IDENTITY(mixed_a, mixed_b);
  TEST_MOD_IDENTITY(mixed_b, mixed_a);

  TEST_MOD_IDENTITY(-mixed_a, mixed_b);
  TEST_MOD_IDENTITY(mixed_a, -mixed_b);
  TEST_MOD_IDENTITY(-mixed_a, -mixed_b);

#undef TEST_MOD_IDENTITY
}

TEST(Duration, Truncation) {
  const absl::Duration d = absl::Nanoseconds(1234567890);
  const absl::Duration inf = absl::InfiniteDuration();
  for (int unit_sign : {1, -1}) {  // sign shouldn't matter
    EXPECT_EQ(absl::Nanoseconds(1234567890),
              Trunc(d, unit_sign * absl::Nanoseconds(1)));
    EXPECT_EQ(absl::Microseconds(1234567),
              Trunc(d, unit_sign * absl::Microseconds(1)));
    EXPECT_EQ(absl::Milliseconds(1234),
              Trunc(d, unit_sign * absl::Milliseconds(1)));
    EXPECT_EQ(absl::Seconds(1), Trunc(d, unit_sign * absl::Seconds(1)));
    EXPECT_EQ(inf, Trunc(inf, unit_sign * absl::Seconds(1)));

    EXPECT_EQ(absl::Nanoseconds(-1234567890),
              Trunc(-d, unit_sign * absl::Nanoseconds(1)));
    EXPECT_EQ(absl::Microseconds(-1234567),
              Trunc(-d, unit_sign * absl::Microseconds(1)));
    EXPECT_EQ(absl::Milliseconds(-1234),
              Trunc(-d, unit_sign * absl::Milliseconds(1)));
    EXPECT_EQ(absl::Seconds(-1), Trunc(-d, unit_sign * absl::Seconds(1)));
    EXPECT_EQ(-inf, Trunc(-inf, unit_sign * absl::Seconds(1)));
  }
}

TEST(Duration, Flooring) {
  const absl::Duration d = absl::Nanoseconds(1234567890);
  const absl::Duration inf = absl::InfiniteDuration();
  for (int unit_sign : {1, -1}) {  // sign shouldn't matter
    EXPECT_EQ(absl::Nanoseconds(1234567890),
              absl::Floor(d, unit_sign * absl::Nanoseconds(1)));
    EXPECT_EQ(absl::Microseconds(1234567),
              absl::Floor(d, unit_sign * absl::Microseconds(1)));
    EXPECT_EQ(absl::Milliseconds(1234),
              absl::Floor(d, unit_sign * absl::Milliseconds(1)));
    EXPECT_EQ(absl::Seconds(1), absl::Floor(d, unit_sign * absl::Seconds(1)));
    EXPECT_EQ(inf, absl::Floor(inf, unit_sign * absl::Seconds(1)));

    EXPECT_EQ(absl::Nanoseconds(-1234567890),
              absl::Floor(-d, unit_sign * absl::Nanoseconds(1)));
    EXPECT_EQ(absl::Microseconds(-1234568),
              absl::Floor(-d, unit_sign * absl::Microseconds(1)));
    EXPECT_EQ(absl::Milliseconds(-1235),
              absl::Floor(-d, unit_sign * absl::Milliseconds(1)));
    EXPECT_EQ(absl::Seconds(-2), absl::Floor(-d, unit_sign * absl::Seconds(1)));
    EXPECT_EQ(-inf, absl::Floor(-inf, unit_sign * absl::Seconds(1)));
  }
}

TEST(Duration, Ceiling) {
  const absl::Duration d = absl::Nanoseconds(1234567890);
  const absl::Duration inf = absl::InfiniteDuration();
  for (int unit_sign : {1, -1}) {  // // sign shouldn't matter
    EXPECT_EQ(absl::Nanoseconds(1234567890),
              absl::Ceil(d, unit_sign * absl::Nanoseconds(1)));
    EXPECT_EQ(absl::Microseconds(1234568),
              absl::Ceil(d, unit_sign * absl::Microseconds(1)));
    EXPECT_EQ(absl::Milliseconds(1235),
              absl::Ceil(d, unit_sign * absl::Milliseconds(1)));
    EXPECT_EQ(absl::Seconds(2), absl::Ceil(d, unit_sign * absl::Seconds(1)));
    EXPECT_EQ(inf, absl::Ceil(inf, unit_sign * absl::Seconds(1)));

    EXPECT_EQ(absl::Nanoseconds(-1234567890),
              absl::Ceil(-d, unit_sign * absl::Nanoseconds(1)));
    EXPECT_EQ(absl::Microseconds(-1234567),
              absl::Ceil(-d, unit_sign * absl::Microseconds(1)));
    EXPECT_EQ(absl::Milliseconds(-1234),
              absl::Ceil(-d, unit_sign * absl::Milliseconds(1)));
    EXPECT_EQ(absl::Seconds(-1), absl::Ceil(-d, unit_sign * absl::Seconds(1)));
    EXPECT_EQ(-inf, absl::Ceil(-inf, unit_sign * absl::Seconds(1)));
  }
}

TEST(Duration, RoundTripUnits) {
  const int kRange = 100000;

#define ROUND_TRIP_UNIT(U, LOW, HIGH)          \
  do {                                         \
    for (int64_t i = LOW; i < HIGH; ++i) {     \
      absl::Duration d = absl::U(i);           \
      if (d == absl::InfiniteDuration())       \
        EXPECT_EQ(kint64max, d / absl::U(1));  \
      else if (d == -absl::InfiniteDuration()) \
        EXPECT_EQ(kint64min, d / absl::U(1));  \
      else                                     \
        EXPECT_EQ(i, absl::U(i) / absl::U(1)); \
    }                                          \
  } while (0)

  ROUND_TRIP_UNIT(Nanoseconds, kint64min, kint64min + kRange);
  ROUND_TRIP_UNIT(Nanoseconds, -kRange, kRange);
  ROUND_TRIP_UNIT(Nanoseconds, kint64max - kRange, kint64max);

  ROUND_TRIP_UNIT(Microseconds, kint64min, kint64min + kRange);
  ROUND_TRIP_UNIT(Microseconds, -kRange, kRange);
  ROUND_TRIP_UNIT(Microseconds, kint64max - kRange, kint64max);

  ROUND_TRIP_UNIT(Milliseconds, kint64min, kint64min + kRange);
  ROUND_TRIP_UNIT(Milliseconds, -kRange, kRange);
  ROUND_TRIP_UNIT(Milliseconds, kint64max - kRange, kint64max);

  ROUND_TRIP_UNIT(Seconds, kint64min, kint64min + kRange);
  ROUND_TRIP_UNIT(Seconds, -kRange, kRange);
  ROUND_TRIP_UNIT(Seconds, kint64max - kRange, kint64max);

  ROUND_TRIP_UNIT(Minutes, kint64min / 60, kint64min / 60 + kRange);
  ROUND_TRIP_UNIT(Minutes, -kRange, kRange);
  ROUND_TRIP_UNIT(Minutes, kint64max / 60 - kRange, kint64max / 60);

  ROUND_TRIP_UNIT(Hours, kint64min / 3600, kint64min / 3600 + kRange);
  ROUND_TRIP_UNIT(Hours, -kRange, kRange);
  ROUND_TRIP_UNIT(Hours, kint64max / 3600 - kRange, kint64max / 3600);

#undef ROUND_TRIP_UNIT
}

TEST(Duration, TruncConversions) {
  // Tests ToTimespec()/DurationFromTimespec()
  const struct {
    absl::Duration d;
    timespec ts;
  } to_ts[] = {
      {absl::Seconds(1) + absl::Nanoseconds(1), {1, 1}},
      {absl::Seconds(1) + absl::Nanoseconds(1) / 2, {1, 0}},
      {absl::Seconds(1) + absl::Nanoseconds(0), {1, 0}},
      {absl::Seconds(0) + absl::Nanoseconds(0), {0, 0}},
      {absl::Seconds(0) - absl::Nanoseconds(1) / 2, {0, 0}},
      {absl::Seconds(0) - absl::Nanoseconds(1), {-1, 999999999}},
      {absl::Seconds(-1) + absl::Nanoseconds(1), {-1, 1}},
      {absl::Seconds(-1) + absl::Nanoseconds(1) / 2, {-1, 1}},
      {absl::Seconds(-1) + absl::Nanoseconds(0), {-1, 0}},
      {absl::Seconds(-1) - absl::Nanoseconds(1) / 2, {-1, 0}},
  };
  for (const auto& test : to_ts) {
    EXPECT_THAT(absl::ToTimespec(test.d), TimespecMatcher(test.ts));
  }
  const struct {
    timespec ts;
    absl::Duration d;
  } from_ts[] = {
      {{1, 1}, absl::Seconds(1) + absl::Nanoseconds(1)},
      {{1, 0}, absl::Seconds(1) + absl::Nanoseconds(0)},
      {{0, 0}, absl::Seconds(0) + absl::Nanoseconds(0)},
      {{0, -1}, absl::Seconds(0) - absl::Nanoseconds(1)},
      {{-1, 999999999}, absl::Seconds(0) - absl::Nanoseconds(1)},
      {{-1, 1}, absl::Seconds(-1) + absl::Nanoseconds(1)},
      {{-1, 0}, absl::Seconds(-1) + absl::Nanoseconds(0)},
      {{-1, -1}, absl::Seconds(-1) - absl::Nanoseconds(1)},
      {{-2, 999999999}, absl::Seconds(-1) - absl::Nanoseconds(1)},
  };
  for (const auto& test : from_ts) {
    EXPECT_EQ(test.d, absl::DurationFromTimespec(test.ts));
  }

  // Tests ToTimeval()/DurationFromTimeval() (same as timespec above)
  const struct {
    absl::Duration d;
    timeval tv;
  } to_tv[] = {
      {absl::Seconds(1) + absl::Microseconds(1), {1, 1}},
      {absl::Seconds(1) + absl::Microseconds(1) / 2, {1, 0}},
      {absl::Seconds(1) + absl::Microseconds(0), {1, 0}},
      {absl::Seconds(0) + absl::Microseconds(0), {0, 0}},
      {absl::Seconds(0) - absl::Microseconds(1) / 2, {0, 0}},
      {absl::Seconds(0) - absl::Microseconds(1), {-1, 999999}},
      {absl::Seconds(-1) + absl::Microseconds(1), {-1, 1}},
      {absl::Seconds(-1) + absl::Microseconds(1) / 2, {-1, 1}},
      {absl::Seconds(-1) + absl::Microseconds(0), {-1, 0}},
      {absl::Seconds(-1) - absl::Microseconds(1) / 2, {-1, 0}},
  };
  for (const auto& test : to_tv) {
    EXPECT_THAT(absl::ToTimeval(test.d), TimevalMatcher(test.tv));
  }
  const struct {
    timeval tv;
    absl::Duration d;
  } from_tv[] = {
      {{1, 1}, absl::Seconds(1) + absl::Microseconds(1)},
      {{1, 0}, absl::Seconds(1) + absl::Microseconds(0)},
      {{0, 0}, absl::Seconds(0) + absl::Microseconds(0)},
      {{0, -1}, absl::Seconds(0) - absl::Microseconds(1)},
      {{-1, 999999}, absl::Seconds(0) - absl::Microseconds(1)},
      {{-1, 1}, absl::Seconds(-1) + absl::Microseconds(1)},
      {{-1, 0}, absl::Seconds(-1) + absl::Microseconds(0)},
      {{-1, -1}, absl::Seconds(-1) - absl::Microseconds(1)},
      {{-2, 999999}, absl::Seconds(-1) - absl::Microseconds(1)},
  };
  for (const auto& test : from_tv) {
    EXPECT_EQ(test.d, absl::DurationFromTimeval(test.tv));
  }
}

TEST(Duration, SmallConversions) {
  // Special tests for conversions of small durations.

  EXPECT_EQ(absl::ZeroDuration(), absl::Seconds(0));
  // TODO(bww): Is the next one OK?
  EXPECT_EQ(absl::ZeroDuration(), absl::Seconds(0.124999999e-9));
  EXPECT_EQ(absl::Nanoseconds(1) / 4, absl::Seconds(0.125e-9));
  EXPECT_EQ(absl::Nanoseconds(1) / 4, absl::Seconds(0.250e-9));
  EXPECT_EQ(absl::Nanoseconds(1) / 2, absl::Seconds(0.375e-9));
  EXPECT_EQ(absl::Nanoseconds(1) / 2, absl::Seconds(0.500e-9));
  EXPECT_EQ(absl::Nanoseconds(3) / 4, absl::Seconds(0.625e-9));
  EXPECT_EQ(absl::Nanoseconds(3) / 4, absl::Seconds(0.750e-9));
  EXPECT_EQ(absl::Nanoseconds(1), absl::Seconds(0.875e-9));
  EXPECT_EQ(absl::Nanoseconds(1), absl::Seconds(1.000e-9));

  EXPECT_EQ(absl::ZeroDuration(), absl::Seconds(-0.124999999e-9));
  EXPECT_EQ(-absl::Nanoseconds(1) / 4, absl::Seconds(-0.125e-9));
  EXPECT_EQ(-absl::Nanoseconds(1) / 4, absl::Seconds(-0.250e-9));
  EXPECT_EQ(-absl::Nanoseconds(1) / 2, absl::Seconds(-0.375e-9));
  EXPECT_EQ(-absl::Nanoseconds(1) / 2, absl::Seconds(-0.500e-9));
  EXPECT_EQ(-absl::Nanoseconds(3) / 4, absl::Seconds(-0.625e-9));
  EXPECT_EQ(-absl::Nanoseconds(3) / 4, absl::Seconds(-0.750e-9));
  EXPECT_EQ(-absl::Nanoseconds(1), absl::Seconds(-0.875e-9));
  EXPECT_EQ(-absl::Nanoseconds(1), absl::Seconds(-1.000e-9));

  timespec ts;
  ts.tv_sec = 0;
  ts.tv_nsec = 0;
  EXPECT_THAT(ToTimespec(absl::Nanoseconds(0)), TimespecMatcher(ts));
  // TODO(bww): Are the next three OK?
  EXPECT_THAT(ToTimespec(absl::Nanoseconds(1) / 4), TimespecMatcher(ts));
  EXPECT_THAT(ToTimespec(absl::Nanoseconds(2) / 4), TimespecMatcher(ts));
  EXPECT_THAT(ToTimespec(absl::Nanoseconds(3) / 4), TimespecMatcher(ts));
  ts.tv_nsec = 1;
  EXPECT_THAT(ToTimespec(absl::Nanoseconds(4) / 4), TimespecMatcher(ts));
  EXPECT_THAT(ToTimespec(absl::Nanoseconds(5) / 4), TimespecMatcher(ts));
  EXPECT_THAT(ToTimespec(absl::Nanoseconds(6) / 4), TimespecMatcher(ts));
  EXPECT_THAT(ToTimespec(absl::Nanoseconds(7) / 4), TimespecMatcher(ts));
  ts.tv_nsec = 2;
  EXPECT_THAT(ToTimespec(absl::Nanoseconds(8) / 4), TimespecMatcher(ts));

  timeval tv;
  tv.tv_sec = 0;
  tv.tv_usec = 0;
  EXPECT_THAT(ToTimeval(absl::Nanoseconds(0)), TimevalMatcher(tv));
  // TODO(bww): Is the next one OK?
  EXPECT_THAT(ToTimeval(absl::Nanoseconds(999)), TimevalMatcher(tv));
  tv.tv_usec = 1;
  EXPECT_THAT(ToTimeval(absl::Nanoseconds(1000)), TimevalMatcher(tv));
  EXPECT_THAT(ToTimeval(absl::Nanoseconds(1999)), TimevalMatcher(tv));
  tv.tv_usec = 2;
  EXPECT_THAT(ToTimeval(absl::Nanoseconds(2000)), TimevalMatcher(tv));
}

void VerifySameAsMul(double time_as_seconds, int* const misses) {
  auto direct_seconds = absl::Seconds(time_as_seconds);
  auto mul_by_one_second = time_as_seconds * absl::Seconds(1);
  if (direct_seconds != mul_by_one_second) {
    if (*misses > 10) return;
    ASSERT_LE(++(*misses), 10) << "Too many errors, not reporting more.";
    EXPECT_EQ(direct_seconds, mul_by_one_second)
        << "given double time_as_seconds = " << std::setprecision(17)
        << time_as_seconds;
  }
}

// For a variety of interesting durations, we find the exact point
// where one double converts to that duration, and the very next double
// converts to the next duration.  For both of those points, verify that
// Seconds(point) returns the same duration as point * Seconds(1.0)
TEST(Duration, ToDoubleSecondsCheckEdgeCases) {
  constexpr uint32_t kTicksPerSecond = absl::time_internal::kTicksPerSecond;
  constexpr auto duration_tick = absl::time_internal::MakeDuration(0, 1u);
  int misses = 0;
  for (int64_t seconds = 0; seconds < 99; ++seconds) {
    uint32_t tick_vals[] = {0, +999, +999999, +999999999, kTicksPerSecond - 1,
                            0, 1000, 1000000, 1000000000, kTicksPerSecond,
                            1, 1001, 1000001, 1000000001, kTicksPerSecond + 1,
                            2, 1002, 1000002, 1000000002, kTicksPerSecond + 2,
                            3, 1003, 1000003, 1000000003, kTicksPerSecond + 3,
                            4, 1004, 1000004, 1000000004, kTicksPerSecond + 4,
                            5, 6,    7,       8,          9};
    for (uint32_t ticks : tick_vals) {
      absl::Duration s_plus_t = absl::Seconds(seconds) + ticks * duration_tick;
      for (absl::Duration d : {s_plus_t, -s_plus_t}) {
        absl::Duration after_d = d + duration_tick;
        EXPECT_NE(d, after_d);
        EXPECT_EQ(after_d - d, duration_tick);

        double low_edge = ToDoubleSeconds(d);
        EXPECT_EQ(d, absl::Seconds(low_edge));

        double high_edge = ToDoubleSeconds(after_d);
        EXPECT_EQ(after_d, absl::Seconds(high_edge));

        for (;;) {
          double midpoint = low_edge + (high_edge - low_edge) / 2;
          if (midpoint == low_edge || midpoint == high_edge) break;
          absl::Duration mid_duration = absl::Seconds(midpoint);
          if (mid_duration == d) {
            low_edge = midpoint;
          } else {
            EXPECT_EQ(mid_duration, after_d);
            high_edge = midpoint;
          }
        }
        // Now low_edge is the highest double that converts to Duration d,
        // and high_edge is the lowest double that converts to Duration after_d.
        VerifySameAsMul(low_edge, &misses);
        VerifySameAsMul(high_edge, &misses);
      }
    }
  }
}

TEST(Duration, ToDoubleSecondsCheckRandom) {
  std::random_device rd;
  std::seed_seq seed({rd(), rd(), rd(), rd(), rd(), rd(), rd(), rd()});
  std::mt19937_64 gen(seed);
  // We want doubles distributed from 1/8ns up to 2^63, where
  // as many values are tested from 1ns to 2ns as from 1sec to 2sec,
  // so even distribute along a log-scale of those values, and
  // exponentiate before using them.  (9.223377e+18 is just slightly
  // out of bounds for absl::Duration.)
  std::uniform_real_distribution<double> uniform(std::log(0.125e-9),
                                                 std::log(9.223377e+18));
  int misses = 0;
  for (int i = 0; i < 1000000; ++i) {
    double d = std::exp(uniform(gen));
    VerifySameAsMul(d, &misses);
    VerifySameAsMul(-d, &misses);
  }
}

TEST(Duration, ConversionSaturation) {
  absl::Duration d;

  const auto max_timeval_sec =
      std::numeric_limits<decltype(timeval::tv_sec)>::max();
  const auto min_timeval_sec =
      std::numeric_limits<decltype(timeval::tv_sec)>::min();
  timeval tv;
  tv.tv_sec = max_timeval_sec;
  tv.tv_usec = 999998;
  d = absl::DurationFromTimeval(tv);
  tv = ToTimeval(d);
  EXPECT_EQ(max_timeval_sec, tv.tv_sec);
  EXPECT_EQ(999998, tv.tv_usec);
  d += absl::Microseconds(1);
  tv = ToTimeval(d);
  EXPECT_EQ(max_timeval_sec, tv.tv_sec);
  EXPECT_EQ(999999, tv.tv_usec);
  d += absl::Microseconds(1);  // no effect
  tv = ToTimeval(d);
  EXPECT_EQ(max_timeval_sec, tv.tv_sec);
  EXPECT_EQ(999999, tv.tv_usec);

  tv.tv_sec = min_timeval_sec;
  tv.tv_usec = 1;
  d = absl::DurationFromTimeval(tv);
  tv = ToTimeval(d);
  EXPECT_EQ(min_timeval_sec, tv.tv_sec);
  EXPECT_EQ(1, tv.tv_usec);
  d -= absl::Microseconds(1);
  tv = ToTimeval(d);
  EXPECT_EQ(min_timeval_sec, tv.tv_sec);
  EXPECT_EQ(0, tv.tv_usec);
  d -= absl::Microseconds(1);  // no effect
  tv = ToTimeval(d);
  EXPECT_EQ(min_timeval_sec, tv.tv_sec);
  EXPECT_EQ(0, tv.tv_usec);

  const auto max_timespec_sec =
      std::numeric_limits<decltype(timespec::tv_sec)>::max();
  const auto min_timespec_sec =
      std::numeric_limits<decltype(timespec::tv_sec)>::min();
  timespec ts;
  ts.tv_sec = max_timespec_sec;
  ts.tv_nsec = 999999998;
  d = absl::DurationFromTimespec(ts);
  ts = absl::ToTimespec(d);
  EXPECT_EQ(max_timespec_sec, ts.tv_sec);
  EXPECT_EQ(999999998, ts.tv_nsec);
  d += absl::Nanoseconds(1);
  ts = absl::ToTimespec(d);
  EXPECT_EQ(max_timespec_sec, ts.tv_sec);
  EXPECT_EQ(999999999, ts.tv_nsec);
  d += absl::Nanoseconds(1);  // no effect
  ts = absl::ToTimespec(d);
  EXPECT_EQ(max_timespec_sec, ts.tv_sec);
  EXPECT_EQ(999999999, ts.tv_nsec);

  ts.tv_sec = min_timespec_sec;
  ts.tv_nsec = 1;
  d = absl::DurationFromTimespec(ts);
  ts = absl::ToTimespec(d);
  EXPECT_EQ(min_timespec_sec, ts.tv_sec);
  EXPECT_EQ(1, ts.tv_nsec);
  d -= absl::Nanoseconds(1);
  ts = absl::ToTimespec(d);
  EXPECT_EQ(min_timespec_sec, ts.tv_sec);
  EXPECT_EQ(0, ts.tv_nsec);
  d -= absl::Nanoseconds(1);  // no effect
  ts = absl::ToTimespec(d);
  EXPECT_EQ(min_timespec_sec, ts.tv_sec);
  EXPECT_EQ(0, ts.tv_nsec);
}

TEST(Duration, FormatDuration) {
  // Example from Go's docs.
  EXPECT_EQ("72h3m0.5s",
            absl::FormatDuration(absl::Hours(72) + absl::Minutes(3) +
                                 absl::Milliseconds(500)));
  // Go's largest time: 2540400h10m10.000000000s
  EXPECT_EQ("2540400h10m10s",
            absl::FormatDuration(absl::Hours(2540400) + absl::Minutes(10) +
                                 absl::Seconds(10)));

  EXPECT_EQ("0", absl::FormatDuration(absl::ZeroDuration()));
  EXPECT_EQ("0", absl::FormatDuration(absl::Seconds(0)));
  EXPECT_EQ("0", absl::FormatDuration(absl::Nanoseconds(0)));

  EXPECT_EQ("1ns", absl::FormatDuration(absl::Nanoseconds(1)));
  EXPECT_EQ("1us", absl::FormatDuration(absl::Microseconds(1)));
  EXPECT_EQ("1ms", absl::FormatDuration(absl::Milliseconds(1)));
  EXPECT_EQ("1s", absl::FormatDuration(absl::Seconds(1)));
  EXPECT_EQ("1m", absl::FormatDuration(absl::Minutes(1)));
  EXPECT_EQ("1h", absl::FormatDuration(absl::Hours(1)));

  EXPECT_EQ("1h1m", absl::FormatDuration(absl::Hours(1) + absl::Minutes(1)));
  EXPECT_EQ("1h1s", absl::FormatDuration(absl::Hours(1) + absl::Seconds(1)));
  EXPECT_EQ("1m1s", absl::FormatDuration(absl::Minutes(1) + absl::Seconds(1)));

  EXPECT_EQ("1h0.25s",
            absl::FormatDuration(absl::Hours(1) + absl::Milliseconds(250)));
  EXPECT_EQ("1m0.25s",
            absl::FormatDuration(absl::Minutes(1) + absl::Milliseconds(250)));
  EXPECT_EQ("1h1m0.25s",
            absl::FormatDuration(absl::Hours(1) + absl::Minutes(1) +
                                 absl::Milliseconds(250)));
  EXPECT_EQ("1h0.0005s",
            absl::FormatDuration(absl::Hours(1) + absl::Microseconds(500)));
  EXPECT_EQ("1h0.0000005s",
            absl::FormatDuration(absl::Hours(1) + absl::Nanoseconds(500)));

  // Subsecond special case.
  EXPECT_EQ("1.5ns", absl::FormatDuration(absl::Nanoseconds(1) +
                                          absl::Nanoseconds(1) / 2));
  EXPECT_EQ("1.25ns", absl::FormatDuration(absl::Nanoseconds(1) +
                                           absl::Nanoseconds(1) / 4));
  EXPECT_EQ("1ns", absl::FormatDuration(absl::Nanoseconds(1) +
                                        absl::Nanoseconds(1) / 9));
  EXPECT_EQ("1.2us", absl::FormatDuration(absl::Microseconds(1) +
                                          absl::Nanoseconds(200)));
  EXPECT_EQ("1.2ms", absl::FormatDuration(absl::Milliseconds(1) +
                                          absl::Microseconds(200)));
  EXPECT_EQ("1.0002ms", absl::FormatDuration(absl::Milliseconds(1) +
                                             absl::Nanoseconds(200)));
  EXPECT_EQ("1.00001ms", absl::FormatDuration(absl::Milliseconds(1) +
                                              absl::Nanoseconds(10)));
  EXPECT_EQ("1.000001ms",
            absl::FormatDuration(absl::Milliseconds(1) + absl::Nanoseconds(1)));

  // Negative durations.
  EXPECT_EQ("-1ns", absl::FormatDuration(absl::Nanoseconds(-1)));
  EXPECT_EQ("-1us", absl::FormatDuration(absl::Microseconds(-1)));
  EXPECT_EQ("-1ms", absl::FormatDuration(absl::Milliseconds(-1)));
  EXPECT_EQ("-1s", absl::FormatDuration(absl::Seconds(-1)));
  EXPECT_EQ("-1m", absl::FormatDuration(absl::Minutes(-1)));
  EXPECT_EQ("-1h", absl::FormatDuration(absl::Hours(-1)));

  EXPECT_EQ("-1h1m",
            absl::FormatDuration(-(absl::Hours(1) + absl::Minutes(1))));
  EXPECT_EQ("-1h1s",
            absl::FormatDuration(-(absl::Hours(1) + absl::Seconds(1))));
  EXPECT_EQ("-1m1s",
            absl::FormatDuration(-(absl::Minutes(1) + absl::Seconds(1))));

  EXPECT_EQ("-1ns", absl::FormatDuration(absl::Nanoseconds(-1)));
  EXPECT_EQ("-1.2us", absl::FormatDuration(
                          -(absl::Microseconds(1) + absl::Nanoseconds(200))));
  EXPECT_EQ("-1.2ms", absl::FormatDuration(
                          -(absl::Milliseconds(1) + absl::Microseconds(200))));
  EXPECT_EQ("-1.0002ms", absl::FormatDuration(-(absl::Milliseconds(1) +
                                                absl::Nanoseconds(200))));
  EXPECT_EQ("-1.00001ms", absl::FormatDuration(-(absl::Milliseconds(1) +
                                                 absl::Nanoseconds(10))));
  EXPECT_EQ("-1.000001ms", absl::FormatDuration(-(absl::Milliseconds(1) +
                                                  absl::Nanoseconds(1))));

  //
  // Interesting corner cases.
  //

  const absl::Duration qns = absl::Nanoseconds(1) / 4;
  const absl::Duration max_dur =
      absl::Seconds(kint64max) + (absl::Seconds(1) - qns);
  const absl::Duration min_dur = absl::Seconds(kint64min);

  EXPECT_EQ("0.25ns", absl::FormatDuration(qns));
  EXPECT_EQ("-0.25ns", absl::FormatDuration(-qns));
  EXPECT_EQ("2562047788015215h30m7.99999999975s",
            absl::FormatDuration(max_dur));
  EXPECT_EQ("-2562047788015215h30m8s", absl::FormatDuration(min_dur));

  // Tests printing full precision from units that print using FDivDuration
  EXPECT_EQ("55.00000000025s", absl::FormatDuration(absl::Seconds(55) + qns));
  EXPECT_EQ("55.00000025ms",
            absl::FormatDuration(absl::Milliseconds(55) + qns));
  EXPECT_EQ("55.00025us", absl::FormatDuration(absl::Microseconds(55) + qns));
  EXPECT_EQ("55.25ns", absl::FormatDuration(absl::Nanoseconds(55) + qns));

  // Formatting infinity
  EXPECT_EQ("inf", absl::FormatDuration(absl::InfiniteDuration()));
  EXPECT_EQ("-inf", absl::FormatDuration(-absl::InfiniteDuration()));

  // Formatting approximately +/- 100 billion years
  const absl::Duration huge_range = ApproxYears(100000000000);
  EXPECT_EQ("876000000000000h", absl::FormatDuration(huge_range));
  EXPECT_EQ("-876000000000000h", absl::FormatDuration(-huge_range));

  EXPECT_EQ("876000000000000h0.999999999s",
            absl::FormatDuration(huge_range +
                                 (absl::Seconds(1) - absl::Nanoseconds(1))));
  EXPECT_EQ("876000000000000h0.9999999995s",
            absl::FormatDuration(
                huge_range + (absl::Seconds(1) - absl::Nanoseconds(1) / 2)));
  EXPECT_EQ("876000000000000h0.99999999975s",
            absl::FormatDuration(
                huge_range + (absl::Seconds(1) - absl::Nanoseconds(1) / 4)));

  EXPECT_EQ("-876000000000000h0.999999999s",
            absl::FormatDuration(-huge_range -
                                 (absl::Seconds(1) - absl::Nanoseconds(1))));
  EXPECT_EQ("-876000000000000h0.9999999995s",
            absl::FormatDuration(
                -huge_range - (absl::Seconds(1) - absl::Nanoseconds(1) / 2)));
  EXPECT_EQ("-876000000000000h0.99999999975s",
            absl::FormatDuration(
                -huge_range - (absl::Seconds(1) - absl::Nanoseconds(1) / 4)));
}

TEST(Duration, ParseDuration) {
  absl::Duration d;

  // No specified unit. Should only work for zero and infinity.
  EXPECT_TRUE(absl::ParseDuration("0", &d));
  EXPECT_EQ(absl::ZeroDuration(), d);
  EXPECT_TRUE(absl::ParseDuration("+0", &d));
  EXPECT_EQ(absl::ZeroDuration(), d);
  EXPECT_TRUE(absl::ParseDuration("-0", &d));
  EXPECT_EQ(absl::ZeroDuration(), d);

  EXPECT_TRUE(absl::ParseDuration("inf", &d));
  EXPECT_EQ(absl::InfiniteDuration(), d);
  EXPECT_TRUE(absl::ParseDuration("+inf", &d));
  EXPECT_EQ(absl::InfiniteDuration(), d);
  EXPECT_TRUE(absl::ParseDuration("-inf", &d));
  EXPECT_EQ(-absl::InfiniteDuration(), d);
  EXPECT_FALSE(absl::ParseDuration("infBlah", &d));

  // Illegal input forms.
  EXPECT_FALSE(absl::ParseDuration("", &d));
  EXPECT_FALSE(absl::ParseDuration("0.0", &d));
  EXPECT_FALSE(absl::ParseDuration(".0", &d));
  EXPECT_FALSE(absl::ParseDuration(".", &d));
  EXPECT_FALSE(absl::ParseDuration("01", &d));
  EXPECT_FALSE(absl::ParseDuration("1", &d));
  EXPECT_FALSE(absl::ParseDuration("-1", &d));
  EXPECT_FALSE(absl::ParseDuration("2", &d));
  EXPECT_FALSE(absl::ParseDuration("2 s", &d));
  EXPECT_FALSE(absl::ParseDuration(".s", &d));
  EXPECT_FALSE(absl::ParseDuration("-.s", &d));
  EXPECT_FALSE(absl::ParseDuration("s", &d));
  EXPECT_FALSE(absl::ParseDuration(" 2s", &d));
  EXPECT_FALSE(absl::ParseDuration("2s ", &d));
  EXPECT_FALSE(absl::ParseDuration(" 2s ", &d));
  EXPECT_FALSE(absl::ParseDuration("2mt", &d));
  EXPECT_FALSE(absl::ParseDuration("1e3s", &d));

  // One unit type.
  EXPECT_TRUE(absl::ParseDuration("1ns", &d));
  EXPECT_EQ(absl::Nanoseconds(1), d);
  EXPECT_TRUE(absl::ParseDuration("1us", &d));
  EXPECT_EQ(absl::Microseconds(1), d);
  EXPECT_TRUE(absl::ParseDuration("1ms", &d));
  EXPECT_EQ(absl::Milliseconds(1), d);
  EXPECT_TRUE(absl::ParseDuration("1s", &d));
  EXPECT_EQ(absl::Seconds(1), d);
  EXPECT_TRUE(absl::ParseDuration("2m", &d));
  EXPECT_EQ(absl::Minutes(2), d);
  EXPECT_TRUE(absl::ParseDuration("2h", &d));
  EXPECT_EQ(absl::Hours(2), d);

  // Huge counts of a unit.
  EXPECT_TRUE(absl::ParseDuration("9223372036854775807us", &d));
  EXPECT_EQ(absl::Microseconds(9223372036854775807), d);
  EXPECT_TRUE(absl::ParseDuration("-9223372036854775807us", &d));
  EXPECT_EQ(absl::Microseconds(-9223372036854775807), d);

  // Multiple units.
  EXPECT_TRUE(absl::ParseDuration("2h3m4s", &d));
  EXPECT_EQ(absl::Hours(2) + absl::Minutes(3) + absl::Seconds(4), d);
  EXPECT_TRUE(absl::ParseDuration("3m4s5us", &d));
  EXPECT_EQ(absl::Minutes(3) + absl::Seconds(4) + absl::Microseconds(5), d);
  EXPECT_TRUE(absl::ParseDuration("2h3m4s5ms6us7ns", &d));
  EXPECT_EQ(absl::Hours(2) + absl::Minutes(3) + absl::Seconds(4) +
                absl::Milliseconds(5) + absl::Microseconds(6) +
                absl::Nanoseconds(7),
            d);

  // Multiple units out of order.
  EXPECT_TRUE(absl::ParseDuration("2us3m4s5h", &d));
  EXPECT_EQ(absl::Hours(5) + absl::Minutes(3) + absl::Seconds(4) +
                absl::Microseconds(2),
            d);

  // Fractional values of units.
  EXPECT_TRUE(absl::ParseDuration("1.5ns", &d));
  EXPECT_EQ(1.5 * absl::Nanoseconds(1), d);
  EXPECT_TRUE(absl::ParseDuration("1.5us", &d));
  EXPECT_EQ(1.5 * absl::Microseconds(1), d);
  EXPECT_TRUE(absl::ParseDuration("1.5ms", &d));
  EXPECT_EQ(1.5 * absl::Milliseconds(1), d);
  EXPECT_TRUE(absl::ParseDuration("1.5s", &d));
  EXPECT_EQ(1.5 * absl::Seconds(1), d);
  EXPECT_TRUE(absl::ParseDuration("1.5m", &d));
  EXPECT_EQ(1.5 * absl::Minutes(1), d);
  EXPECT_TRUE(absl::ParseDuration("1.5h", &d));
  EXPECT_EQ(1.5 * absl::Hours(1), d);

  // Huge fractional counts of a unit.
  EXPECT_TRUE(absl::ParseDuration("0.4294967295s", &d));
  EXPECT_EQ(absl::Nanoseconds(429496729) + absl::Nanoseconds(1) / 2, d);
  EXPECT_TRUE(absl::ParseDuration("0.429496729501234567890123456789s", &d));
  EXPECT_EQ(absl::Nanoseconds(429496729) + absl::Nanoseconds(1) / 2, d);

  // Negative durations.
  EXPECT_TRUE(absl::ParseDuration("-1s", &d));
  EXPECT_EQ(absl::Seconds(-1), d);
  EXPECT_TRUE(absl::ParseDuration("-1m", &d));
  EXPECT_EQ(absl::Minutes(-1), d);
  EXPECT_TRUE(absl::ParseDuration("-1h", &d));
  EXPECT_EQ(absl::Hours(-1), d);

  EXPECT_TRUE(absl::ParseDuration("-1h2s", &d));
  EXPECT_EQ(-(absl::Hours(1) + absl::Seconds(2)), d);
  EXPECT_FALSE(absl::ParseDuration("1h-2s", &d));
  EXPECT_FALSE(absl::ParseDuration("-1h-2s", &d));
  EXPECT_FALSE(absl::ParseDuration("-1h -2s", &d));
}

TEST(Duration, FormatParseRoundTrip) {
#define TEST_PARSE_ROUNDTRIP(d)                \
  do {                                         \
    std::string s = absl::FormatDuration(d);        \
    absl::Duration dur;                        \
    EXPECT_TRUE(absl::ParseDuration(s, &dur)); \
    EXPECT_EQ(d, dur);                         \
  } while (0)

  TEST_PARSE_ROUNDTRIP(absl::Nanoseconds(1));
  TEST_PARSE_ROUNDTRIP(absl::Microseconds(1));
  TEST_PARSE_ROUNDTRIP(absl::Milliseconds(1));
  TEST_PARSE_ROUNDTRIP(absl::Seconds(1));
  TEST_PARSE_ROUNDTRIP(absl::Minutes(1));
  TEST_PARSE_ROUNDTRIP(absl::Hours(1));
  TEST_PARSE_ROUNDTRIP(absl::Hours(1) + absl::Nanoseconds(2));

  TEST_PARSE_ROUNDTRIP(absl::Nanoseconds(-1));
  TEST_PARSE_ROUNDTRIP(absl::Microseconds(-1));
  TEST_PARSE_ROUNDTRIP(absl::Milliseconds(-1));
  TEST_PARSE_ROUNDTRIP(absl::Seconds(-1));
  TEST_PARSE_ROUNDTRIP(absl::Minutes(-1));
  TEST_PARSE_ROUNDTRIP(absl::Hours(-1));

  TEST_PARSE_ROUNDTRIP(absl::Hours(-1) + absl::Nanoseconds(2));
  TEST_PARSE_ROUNDTRIP(absl::Hours(1) + absl::Nanoseconds(-2));
  TEST_PARSE_ROUNDTRIP(absl::Hours(-1) + absl::Nanoseconds(-2));

  TEST_PARSE_ROUNDTRIP(absl::Nanoseconds(1) +
                       absl::Nanoseconds(1) / 4);  // 1.25ns

  const absl::Duration huge_range = ApproxYears(100000000000);
  TEST_PARSE_ROUNDTRIP(huge_range);
  TEST_PARSE_ROUNDTRIP(huge_range + (absl::Seconds(1) - absl::Nanoseconds(1)));

#undef TEST_PARSE_ROUNDTRIP
}

}  // namespace