Initial Commit

1 files changed, 1027 insertions, 0 deletions

diff --git a/absl/time/time_test.cc b/absl/time/time_test.cc
new file mode 100644
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+++ b/absl/time/time_test.cc
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+// 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 "absl/time/time.h"
+
+#include <cstring>
+#include <ctime>
+#include <iomanip>
+#include <limits>
+#include <string>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/time/clock.h"
+#include "absl/time/internal/test_util.h"
+
+namespace {
+
+// 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(Time, ConstExpr) {
+  constexpr absl::Time t0 = absl::UnixEpoch();
+  static_assert(t0 == absl::Time(), "UnixEpoch");
+  constexpr absl::Time t1 = absl::InfiniteFuture();
+  static_assert(t1 != absl::Time(), "InfiniteFuture");
+  constexpr absl::Time t2 = absl::InfinitePast();
+  static_assert(t2 != absl::Time(), "InfinitePast");
+  constexpr absl::Time t3 = absl::FromUnixNanos(0);
+  static_assert(t3 == absl::Time(), "FromUnixNanos");
+  constexpr absl::Time t4 = absl::FromUnixMicros(0);
+  static_assert(t4 == absl::Time(), "FromUnixMicros");
+  constexpr absl::Time t5 = absl::FromUnixMillis(0);
+  static_assert(t5 == absl::Time(), "FromUnixMillis");
+  constexpr absl::Time t6 = absl::FromUnixSeconds(0);
+  static_assert(t6 == absl::Time(), "FromUnixSeconds");
+  constexpr absl::Time t7 = absl::FromTimeT(0);
+  static_assert(t7 == absl::Time(), "FromTimeT");
+}
+
+TEST(Time, ValueSemantics) {
+  absl::Time a;      // Default construction
+  absl::Time b = a;  // Copy construction
+  EXPECT_EQ(a, b);
+  absl::Time c(a);  // Copy construction (again)
+  EXPECT_EQ(a, b);
+  EXPECT_EQ(a, c);
+  EXPECT_EQ(b, c);
+  b = c;       // Assignment
+  EXPECT_EQ(a, b);
+  EXPECT_EQ(a, c);
+  EXPECT_EQ(b, c);
+}
+
+TEST(Time, UnixEpoch) {
+  absl::Time::Breakdown bd = absl::UnixEpoch().In(absl::UTCTimeZone());
+  ABSL_INTERNAL_EXPECT_TIME(bd, 1970, 1, 1, 0, 0, 0, 0, false, "UTC");
+  EXPECT_EQ(absl::ZeroDuration(), bd.subsecond);
+  EXPECT_EQ(4, bd.weekday);  // Thursday
+}
+
+TEST(Time, Breakdown) {
+  absl::TimeZone tz = absl::time_internal::LoadTimeZone("America/New_York");
+  absl::Time t = absl::UnixEpoch();
+
+  // The Unix epoch as seen in NYC.
+  absl::Time::Breakdown bd = t.In(tz);
+  ABSL_INTERNAL_EXPECT_TIME(bd, 1969, 12, 31, 19, 0, 0, -18000, false, "EST");
+  EXPECT_EQ(absl::ZeroDuration(), bd.subsecond);
+  EXPECT_EQ(3, bd.weekday);  // Wednesday
+
+  // Just before the epoch.
+  t -= absl::Nanoseconds(1);
+  bd = t.In(tz);
+  ABSL_INTERNAL_EXPECT_TIME(bd, 1969, 12, 31, 18, 59, 59, -18000, false, "EST");
+  EXPECT_EQ(absl::Nanoseconds(999999999), bd.subsecond);
+  EXPECT_EQ(3, bd.weekday);  // Wednesday
+
+  // Some time later.
+  t += absl::Hours(24) * 2735;
+  t += absl::Hours(18) + absl::Minutes(30) + absl::Seconds(15) +
+       absl::Nanoseconds(9);
+  bd = t.In(tz);
+  ABSL_INTERNAL_EXPECT_TIME(bd, 1977, 6, 28, 14, 30, 15, -14400, true, "EDT");
+  EXPECT_EQ(8, bd.subsecond / absl::Nanoseconds(1));
+  EXPECT_EQ(2, bd.weekday);  // Tuesday
+}
+
+TEST(Time, AdditiveOperators) {
+  const absl::Duration d = absl::Nanoseconds(1);
+  const absl::Time t0;
+  const absl::Time t1 = t0 + d;
+
+  EXPECT_EQ(d, t1 - t0);
+  EXPECT_EQ(-d, t0 - t1);
+  EXPECT_EQ(t0, t1 - d);
+
+  absl::Time t(t0);
+  EXPECT_EQ(t0, t);
+  t += d;
+  EXPECT_EQ(t0 + d, t);
+  EXPECT_EQ(d, t - t0);
+  t -= d;
+  EXPECT_EQ(t0, t);
+
+  // Tests overflow between subseconds and seconds.
+  t = absl::UnixEpoch();
+  t += absl::Milliseconds(500);
+  EXPECT_EQ(absl::UnixEpoch() + absl::Milliseconds(500), t);
+  t += absl::Milliseconds(600);
+  EXPECT_EQ(absl::UnixEpoch() + absl::Milliseconds(1100), t);
+  t -= absl::Milliseconds(600);
+  EXPECT_EQ(absl::UnixEpoch() + absl::Milliseconds(500), t);
+  t -= absl::Milliseconds(500);
+  EXPECT_EQ(absl::UnixEpoch(), t);
+}
+
+TEST(Time, RelationalOperators) {
+  constexpr absl::Time t1 = absl::FromUnixNanos(0);
+  constexpr absl::Time t2 = absl::FromUnixNanos(1);
+  constexpr absl::Time t3 = absl::FromUnixNanos(2);
+
+  static_assert(absl::Time() == t1, "");
+  static_assert(t1 == t1, "");
+  static_assert(t2 == t2, "");
+  static_assert(t3 == t3, "");
+
+  static_assert(t1 < t2, "");
+  static_assert(t2 < t3, "");
+  static_assert(t1 < t3, "");
+
+  static_assert(t1 <= t1, "");
+  static_assert(t1 <= t2, "");
+  static_assert(t2 <= t2, "");
+  static_assert(t2 <= t3, "");
+  static_assert(t3 <= t3, "");
+  static_assert(t1 <= t3, "");
+
+  static_assert(t2 > t1, "");
+  static_assert(t3 > t2, "");
+  static_assert(t3 > t1, "");
+
+  static_assert(t2 >= t2, "");
+  static_assert(t2 >= t1, "");
+  static_assert(t3 >= t3, "");
+  static_assert(t3 >= t2, "");
+  static_assert(t1 >= t1, "");
+  static_assert(t3 >= t1, "");
+}
+
+TEST(Time, Infinity) {
+  constexpr absl::Time ifuture = absl::InfiniteFuture();
+  constexpr absl::Time ipast = absl::InfinitePast();
+
+  static_assert(ifuture == ifuture, "");
+  static_assert(ipast == ipast, "");
+  static_assert(ipast < ifuture, "");
+  static_assert(ifuture > ipast, "");
+
+  // Arithmetic saturates
+  EXPECT_EQ(ifuture, ifuture + absl::Seconds(1));
+  EXPECT_EQ(ifuture, ifuture - absl::Seconds(1));
+  EXPECT_EQ(ipast, ipast + absl::Seconds(1));
+  EXPECT_EQ(ipast, ipast - absl::Seconds(1));
+
+  EXPECT_EQ(absl::InfiniteDuration(), ifuture - ifuture);
+  EXPECT_EQ(absl::InfiniteDuration(), ifuture - ipast);
+  EXPECT_EQ(-absl::InfiniteDuration(), ipast - ifuture);
+  EXPECT_EQ(-absl::InfiniteDuration(), ipast - ipast);
+
+  constexpr absl::Time t = absl::UnixEpoch();  // Any finite time.
+  static_assert(t < ifuture, "");
+  static_assert(t > ipast, "");
+}
+
+TEST(Time, FloorConversion) {
+#define TEST_FLOOR_CONVERSION(TO, FROM) \
+  EXPECT_EQ(1, TO(FROM(1001)));         \
+  EXPECT_EQ(1, TO(FROM(1000)));         \
+  EXPECT_EQ(0, TO(FROM(999)));          \
+  EXPECT_EQ(0, TO(FROM(1)));            \
+  EXPECT_EQ(0, TO(FROM(0)));            \
+  EXPECT_EQ(-1, TO(FROM(-1)));          \
+  EXPECT_EQ(-1, TO(FROM(-999)));        \
+  EXPECT_EQ(-1, TO(FROM(-1000)));       \
+  EXPECT_EQ(-2, TO(FROM(-1001)));
+
+  TEST_FLOOR_CONVERSION(absl::ToUnixMicros, absl::FromUnixNanos);
+  TEST_FLOOR_CONVERSION(absl::ToUnixMillis, absl::FromUnixMicros);
+  TEST_FLOOR_CONVERSION(absl::ToUnixSeconds, absl::FromUnixMillis);
+  TEST_FLOOR_CONVERSION(absl::ToTimeT, absl::FromUnixMillis);
+
+#undef TEST_FLOOR_CONVERSION
+
+  // Tests ToUnixNanos.
+  EXPECT_EQ(1, absl::ToUnixNanos(absl::UnixEpoch() + absl::Nanoseconds(3) / 2));
+  EXPECT_EQ(1, absl::ToUnixNanos(absl::UnixEpoch() + absl::Nanoseconds(1)));
+  EXPECT_EQ(0, absl::ToUnixNanos(absl::UnixEpoch() + absl::Nanoseconds(1) / 2));
+  EXPECT_EQ(0, absl::ToUnixNanos(absl::UnixEpoch() + absl::Nanoseconds(0)));
+  EXPECT_EQ(-1,
+            absl::ToUnixNanos(absl::UnixEpoch() - absl::Nanoseconds(1) / 2));
+  EXPECT_EQ(-1, absl::ToUnixNanos(absl::UnixEpoch() - absl::Nanoseconds(1)));
+  EXPECT_EQ(-2,
+            absl::ToUnixNanos(absl::UnixEpoch() - absl::Nanoseconds(3) / 2));
+
+  // Tests ToUniversal, which uses a different epoch than the tests above.
+  EXPECT_EQ(1,
+            absl::ToUniversal(absl::UniversalEpoch() + absl::Nanoseconds(101)));
+  EXPECT_EQ(1,
+            absl::ToUniversal(absl::UniversalEpoch() + absl::Nanoseconds(100)));
+  EXPECT_EQ(0,
+            absl::ToUniversal(absl::UniversalEpoch() + absl::Nanoseconds(99)));
+  EXPECT_EQ(0,
+            absl::ToUniversal(absl::UniversalEpoch() + absl::Nanoseconds(1)));
+  EXPECT_EQ(0,
+            absl::ToUniversal(absl::UniversalEpoch() + absl::Nanoseconds(0)));
+  EXPECT_EQ(-1,
+            absl::ToUniversal(absl::UniversalEpoch() + absl::Nanoseconds(-1)));
+  EXPECT_EQ(-1,
+            absl::ToUniversal(absl::UniversalEpoch() + absl::Nanoseconds(-99)));
+  EXPECT_EQ(
+      -1, absl::ToUniversal(absl::UniversalEpoch() + absl::Nanoseconds(-100)));
+  EXPECT_EQ(
+      -2, absl::ToUniversal(absl::UniversalEpoch() + absl::Nanoseconds(-101)));
+
+  // Tests ToTimespec()/TimeFromTimespec()
+  const struct {
+    absl::Time t;
+    timespec ts;
+  } to_ts[] = {
+      {absl::FromUnixSeconds(1) + absl::Nanoseconds(1), {1, 1}},
+      {absl::FromUnixSeconds(1) + absl::Nanoseconds(1) / 2, {1, 0}},
+      {absl::FromUnixSeconds(1) + absl::Nanoseconds(0), {1, 0}},
+      {absl::FromUnixSeconds(0) + absl::Nanoseconds(0), {0, 0}},
+      {absl::FromUnixSeconds(0) - absl::Nanoseconds(1) / 2, {-1, 999999999}},
+      {absl::FromUnixSeconds(0) - absl::Nanoseconds(1), {-1, 999999999}},
+      {absl::FromUnixSeconds(-1) + absl::Nanoseconds(1), {-1, 1}},
+      {absl::FromUnixSeconds(-1) + absl::Nanoseconds(1) / 2, {-1, 0}},
+      {absl::FromUnixSeconds(-1) + absl::Nanoseconds(0), {-1, 0}},
+      {absl::FromUnixSeconds(-1) - absl::Nanoseconds(1) / 2, {-2, 999999999}},
+  };
+  for (const auto& test : to_ts) {
+    EXPECT_THAT(absl::ToTimespec(test.t), TimespecMatcher(test.ts));
+  }
+  const struct {
+    timespec ts;
+    absl::Time t;
+  } from_ts[] = {
+      {{1, 1}, absl::FromUnixSeconds(1) + absl::Nanoseconds(1)},
+      {{1, 0}, absl::FromUnixSeconds(1) + absl::Nanoseconds(0)},
+      {{0, 0}, absl::FromUnixSeconds(0) + absl::Nanoseconds(0)},
+      {{0, -1}, absl::FromUnixSeconds(0) - absl::Nanoseconds(1)},
+      {{-1, 999999999}, absl::FromUnixSeconds(0) - absl::Nanoseconds(1)},
+      {{-1, 1}, absl::FromUnixSeconds(-1) + absl::Nanoseconds(1)},
+      {{-1, 0}, absl::FromUnixSeconds(-1) + absl::Nanoseconds(0)},
+      {{-1, -1}, absl::FromUnixSeconds(-1) - absl::Nanoseconds(1)},
+      {{-2, 999999999}, absl::FromUnixSeconds(-1) - absl::Nanoseconds(1)},
+  };
+  for (const auto& test : from_ts) {
+    EXPECT_EQ(test.t, absl::TimeFromTimespec(test.ts));
+  }
+
+  // Tests ToTimeval()/TimeFromTimeval() (same as timespec above)
+  const struct {
+    absl::Time t;
+    timeval tv;
+  } to_tv[] = {
+      {absl::FromUnixSeconds(1) + absl::Microseconds(1), {1, 1}},
+      {absl::FromUnixSeconds(1) + absl::Microseconds(1) / 2, {1, 0}},
+      {absl::FromUnixSeconds(1) + absl::Microseconds(0), {1, 0}},
+      {absl::FromUnixSeconds(0) + absl::Microseconds(0), {0, 0}},
+      {absl::FromUnixSeconds(0) - absl::Microseconds(1) / 2, {-1, 999999}},
+      {absl::FromUnixSeconds(0) - absl::Microseconds(1), {-1, 999999}},
+      {absl::FromUnixSeconds(-1) + absl::Microseconds(1), {-1, 1}},
+      {absl::FromUnixSeconds(-1) + absl::Microseconds(1) / 2, {-1, 0}},
+      {absl::FromUnixSeconds(-1) + absl::Microseconds(0), {-1, 0}},
+      {absl::FromUnixSeconds(-1) - absl::Microseconds(1) / 2, {-2, 999999}},
+  };
+  for (const auto& test : to_tv) {
+    EXPECT_THAT(ToTimeval(test.t), TimevalMatcher(test.tv));
+  }
+  const struct {
+    timeval tv;
+    absl::Time t;
+  } from_tv[] = {
+      {{1, 1}, absl::FromUnixSeconds(1) + absl::Microseconds(1)},
+      {{1, 0}, absl::FromUnixSeconds(1) + absl::Microseconds(0)},
+      {{0, 0}, absl::FromUnixSeconds(0) + absl::Microseconds(0)},
+      {{0, -1}, absl::FromUnixSeconds(0) - absl::Microseconds(1)},
+      {{-1, 999999}, absl::FromUnixSeconds(0) - absl::Microseconds(1)},
+      {{-1, 1}, absl::FromUnixSeconds(-1) + absl::Microseconds(1)},
+      {{-1, 0}, absl::FromUnixSeconds(-1) + absl::Microseconds(0)},
+      {{-1, -1}, absl::FromUnixSeconds(-1) - absl::Microseconds(1)},
+      {{-2, 999999}, absl::FromUnixSeconds(-1) - absl::Microseconds(1)},
+  };
+  for (const auto& test : from_tv) {
+    EXPECT_EQ(test.t, absl::TimeFromTimeval(test.tv));
+  }
+
+  // Tests flooring near negative infinity.
+  const int64_t min_plus_1 = std::numeric_limits<int64_t>::min() + 1;
+  EXPECT_EQ(min_plus_1, absl::ToUnixSeconds(absl::FromUnixSeconds(min_plus_1)));
+  EXPECT_EQ(std::numeric_limits<int64_t>::min(),
+            absl::ToUnixSeconds(
+                absl::FromUnixSeconds(min_plus_1) - absl::Nanoseconds(1) / 2));
+
+  // Tests flooring near positive infinity.
+  EXPECT_EQ(std::numeric_limits<int64_t>::max(),
+            absl::ToUnixSeconds(absl::FromUnixSeconds(
+                std::numeric_limits<int64_t>::max()) + absl::Nanoseconds(1) / 2));
+  EXPECT_EQ(std::numeric_limits<int64_t>::max(),
+            absl::ToUnixSeconds(
+                absl::FromUnixSeconds(std::numeric_limits<int64_t>::max())));
+  EXPECT_EQ(std::numeric_limits<int64_t>::max() - 1,
+            absl::ToUnixSeconds(absl::FromUnixSeconds(
+                std::numeric_limits<int64_t>::max()) - absl::Nanoseconds(1) / 2));
+}
+
+TEST(Time, RoundtripConversion) {
+#define TEST_CONVERSION_ROUND_TRIP(SOURCE, FROM, TO, MATCHER) \
+  EXPECT_THAT(TO(FROM(SOURCE)), MATCHER(SOURCE))
+
+  // FromUnixNanos() and ToUnixNanos()
+  int64_t now_ns = absl::GetCurrentTimeNanos();
+  TEST_CONVERSION_ROUND_TRIP(-1, absl::FromUnixNanos, absl::ToUnixNanos,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(0, absl::FromUnixNanos, absl::ToUnixNanos,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(1, absl::FromUnixNanos, absl::ToUnixNanos,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(now_ns, absl::FromUnixNanos, absl::ToUnixNanos,
+                             testing::Eq)
+      << now_ns;
+
+  // FromUnixMicros() and ToUnixMicros()
+  int64_t now_us = absl::GetCurrentTimeNanos() / 1000;
+  TEST_CONVERSION_ROUND_TRIP(-1, absl::FromUnixMicros, absl::ToUnixMicros,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(0, absl::FromUnixMicros, absl::ToUnixMicros,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(1, absl::FromUnixMicros, absl::ToUnixMicros,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(now_us, absl::FromUnixMicros, absl::ToUnixMicros,
+                             testing::Eq)
+      << now_us;
+
+  // FromUnixMillis() and ToUnixMillis()
+  int64_t now_ms = absl::GetCurrentTimeNanos() / 1000000;
+  TEST_CONVERSION_ROUND_TRIP(-1, absl::FromUnixMillis, absl::ToUnixMillis,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(0, absl::FromUnixMillis, absl::ToUnixMillis,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(1, absl::FromUnixMillis, absl::ToUnixMillis,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(now_ms, absl::FromUnixMillis, absl::ToUnixMillis,
+                             testing::Eq)
+      << now_ms;
+
+  // FromUnixSeconds() and ToUnixSeconds()
+  int64_t now_s = std::time(nullptr);
+  TEST_CONVERSION_ROUND_TRIP(-1, absl::FromUnixSeconds, absl::ToUnixSeconds,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(0, absl::FromUnixSeconds, absl::ToUnixSeconds,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(1, absl::FromUnixSeconds, absl::ToUnixSeconds,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(now_s, absl::FromUnixSeconds, absl::ToUnixSeconds,
+                             testing::Eq)
+      << now_s;
+
+  // FromTimeT() and ToTimeT()
+  time_t now_time_t = std::time(nullptr);
+  TEST_CONVERSION_ROUND_TRIP(-1, absl::FromTimeT, absl::ToTimeT, testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(0, absl::FromTimeT, absl::ToTimeT, testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(1, absl::FromTimeT, absl::ToTimeT, testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(now_time_t, absl::FromTimeT, absl::ToTimeT,
+                             testing::Eq)
+      << now_time_t;
+
+  // TimeFromTimeval() and ToTimeval()
+  timeval tv;
+  tv.tv_sec = -1;
+  tv.tv_usec = 0;
+  TEST_CONVERSION_ROUND_TRIP(tv, absl::TimeFromTimeval, absl::ToTimeval,
+                             TimevalMatcher);
+  tv.tv_sec = -1;
+  tv.tv_usec = 999999;
+  TEST_CONVERSION_ROUND_TRIP(tv, absl::TimeFromTimeval, absl::ToTimeval,
+                             TimevalMatcher);
+  tv.tv_sec = 0;
+  tv.tv_usec = 0;
+  TEST_CONVERSION_ROUND_TRIP(tv, absl::TimeFromTimeval, absl::ToTimeval,
+                             TimevalMatcher);
+  tv.tv_sec = 0;
+  tv.tv_usec = 1;
+  TEST_CONVERSION_ROUND_TRIP(tv, absl::TimeFromTimeval, absl::ToTimeval,
+                             TimevalMatcher);
+  tv.tv_sec = 1;
+  tv.tv_usec = 0;
+  TEST_CONVERSION_ROUND_TRIP(tv, absl::TimeFromTimeval, absl::ToTimeval,
+                             TimevalMatcher);
+
+  // TimeFromTimespec() and ToTimespec()
+  timespec ts;
+  ts.tv_sec = -1;
+  ts.tv_nsec = 0;
+  TEST_CONVERSION_ROUND_TRIP(ts, absl::TimeFromTimespec, absl::ToTimespec,
+                             TimespecMatcher);
+  ts.tv_sec = -1;
+  ts.tv_nsec = 999999999;
+  TEST_CONVERSION_ROUND_TRIP(ts, absl::TimeFromTimespec, absl::ToTimespec,
+                             TimespecMatcher);
+  ts.tv_sec = 0;
+  ts.tv_nsec = 0;
+  TEST_CONVERSION_ROUND_TRIP(ts, absl::TimeFromTimespec, absl::ToTimespec,
+                             TimespecMatcher);
+  ts.tv_sec = 0;
+  ts.tv_nsec = 1;
+  TEST_CONVERSION_ROUND_TRIP(ts, absl::TimeFromTimespec, absl::ToTimespec,
+                             TimespecMatcher);
+  ts.tv_sec = 1;
+  ts.tv_nsec = 0;
+  TEST_CONVERSION_ROUND_TRIP(ts, absl::TimeFromTimespec, absl::ToTimespec,
+                             TimespecMatcher);
+
+  // FromUDate() and ToUDate()
+  double now_ud = absl::GetCurrentTimeNanos() / 1000000;
+  TEST_CONVERSION_ROUND_TRIP(-1.5, absl::FromUDate, absl::ToUDate,
+                             testing::DoubleEq);
+  TEST_CONVERSION_ROUND_TRIP(-1, absl::FromUDate, absl::ToUDate,
+                             testing::DoubleEq);
+  TEST_CONVERSION_ROUND_TRIP(-0.5, absl::FromUDate, absl::ToUDate,
+                             testing::DoubleEq);
+  TEST_CONVERSION_ROUND_TRIP(0, absl::FromUDate, absl::ToUDate,
+                             testing::DoubleEq);
+  TEST_CONVERSION_ROUND_TRIP(0.5, absl::FromUDate, absl::ToUDate,
+                             testing::DoubleEq);
+  TEST_CONVERSION_ROUND_TRIP(1, absl::FromUDate, absl::ToUDate,
+                             testing::DoubleEq);
+  TEST_CONVERSION_ROUND_TRIP(1.5, absl::FromUDate, absl::ToUDate,
+                             testing::DoubleEq);
+  TEST_CONVERSION_ROUND_TRIP(now_ud, absl::FromUDate, absl::ToUDate,
+                             testing::DoubleEq)
+      << std::fixed << std::setprecision(17) << now_ud;
+
+  // FromUniversal() and ToUniversal()
+  int64_t now_uni = ((719162LL * (24 * 60 * 60)) * (1000 * 1000 * 10)) +
+                    (absl::GetCurrentTimeNanos() / 100);
+  TEST_CONVERSION_ROUND_TRIP(-1, absl::FromUniversal, absl::ToUniversal,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(0, absl::FromUniversal, absl::ToUniversal,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(1, absl::FromUniversal, absl::ToUniversal,
+                             testing::Eq);
+  TEST_CONVERSION_ROUND_TRIP(now_uni, absl::FromUniversal, absl::ToUniversal,
+                             testing::Eq)
+      << now_uni;
+
+#undef TEST_CONVERSION_ROUND_TRIP
+}
+
+TEST(Time, ConvertDateTime) {
+  const absl::TimeZone utc = absl::UTCTimeZone();
+  const absl::TimeZone goog =
+      absl::time_internal::LoadTimeZone("America/Los_Angeles");
+  const absl::TimeZone nyc =
+      absl::time_internal::LoadTimeZone("America/New_York");
+  const std::string fmt = "%a, %e %b %Y %H:%M:%S %z (%Z)";
+
+  // A simple case of normalization.
+  absl::TimeConversion oct32 = ConvertDateTime(2013, 10, 32, 8, 30, 0, goog);
+  EXPECT_TRUE(oct32.normalized);
+  EXPECT_EQ(absl::TimeConversion::UNIQUE, oct32.kind);
+  absl::TimeConversion nov01 = ConvertDateTime(2013, 11, 1, 8, 30, 0, goog);
+  EXPECT_FALSE(nov01.normalized);
+  EXPECT_EQ(absl::TimeConversion::UNIQUE, nov01.kind);
+  EXPECT_EQ(oct32.pre, nov01.pre);
+  EXPECT_EQ("Fri,  1 Nov 2013 08:30:00 -0700 (PDT)",
+            absl::FormatTime(fmt, nov01.pre, goog));
+
+  // A Spring DST transition, when there is a gap in civil time
+  // and we prefer the later of the possible interpretations of a
+  // non-existent time.
+  absl::TimeConversion mar13 = ConvertDateTime(2011, 3, 13, 2, 15, 0, nyc);
+  EXPECT_FALSE(mar13.normalized);
+  EXPECT_EQ(absl::TimeConversion::SKIPPED, mar13.kind);
+  EXPECT_EQ("Sun, 13 Mar 2011 03:15:00 -0400 (EDT)",
+            absl::FormatTime(fmt, mar13.pre, nyc));
+  EXPECT_EQ("Sun, 13 Mar 2011 03:00:00 -0400 (EDT)",
+            absl::FormatTime(fmt, mar13.trans, nyc));
+  EXPECT_EQ("Sun, 13 Mar 2011 01:15:00 -0500 (EST)",
+            absl::FormatTime(fmt, mar13.post, nyc));
+  EXPECT_EQ(mar13.pre, absl::FromDateTime(2011, 3, 13, 2, 15, 0, nyc));
+
+  // A Fall DST transition, when civil times are repeated and
+  // we prefer the earlier of the possible interpretations of an
+  // ambiguous time.
+  absl::TimeConversion nov06 = ConvertDateTime(2011, 11, 6, 1, 15, 0, nyc);
+  EXPECT_FALSE(nov06.normalized);
+  EXPECT_EQ(absl::TimeConversion::REPEATED, nov06.kind);
+  EXPECT_EQ("Sun,  6 Nov 2011 01:15:00 -0400 (EDT)",
+            absl::FormatTime(fmt, nov06.pre, nyc));
+  EXPECT_EQ("Sun,  6 Nov 2011 01:00:00 -0500 (EST)",
+            absl::FormatTime(fmt, nov06.trans, nyc));
+  EXPECT_EQ("Sun,  6 Nov 2011 01:15:00 -0500 (EST)",
+            absl::FormatTime(fmt, nov06.post, nyc));
+  EXPECT_EQ(nov06.pre, absl::FromDateTime(2011, 11, 6, 1, 15, 0, nyc));
+
+  // Check that (time_t) -1 is handled correctly.
+  absl::TimeConversion minus1 = ConvertDateTime(1969, 12, 31, 18, 59, 59, nyc);
+  EXPECT_FALSE(minus1.normalized);
+  EXPECT_EQ(absl::TimeConversion::UNIQUE, minus1.kind);
+  EXPECT_EQ(-1, absl::ToTimeT(minus1.pre));
+  EXPECT_EQ("Wed, 31 Dec 1969 18:59:59 -0500 (EST)",
+            absl::FormatTime(fmt, minus1.pre, nyc));
+  EXPECT_EQ("Wed, 31 Dec 1969 23:59:59 +0000 (UTC)",
+            absl::FormatTime(fmt, minus1.pre, utc));
+}
+
+// FromDateTime(year, mon, day, hour, min, sec, UTCTimeZone()) has
+// a specialized fastpath implementation which we exercise here.
+TEST(Time, FromDateTimeUTC) {
+  const absl::TimeZone utc = absl::UTCTimeZone();
+  const std::string fmt = "%a, %e %b %Y %H:%M:%S %z (%Z)";
+  const int kMax = std::numeric_limits<int>::max();
+  const int kMin = std::numeric_limits<int>::min();
+  absl::Time t;
+
+  // 292091940881 is the last positive year to use the fastpath.
+  t = absl::FromDateTime(292091940881, kMax, kMax, kMax, kMax, kMax, utc);
+  EXPECT_EQ("Fri, 25 Nov 292277026596 12:21:07 +0000 (UTC)",
+            absl::FormatTime(fmt, t, utc));
+  t = absl::FromDateTime(292091940882, kMax, kMax, kMax, kMax, kMax, utc);
+  EXPECT_EQ("infinite-future", absl::FormatTime(fmt, t, utc));  // no overflow
+  t = absl::FromDateTime(
+      std::numeric_limits<int64_t>::max(), kMax, kMax, kMax, kMax, kMax, utc);
+  EXPECT_EQ("infinite-future", absl::FormatTime(fmt, t, utc));  // no overflow
+
+  // -292091936940 is the last negative year to use the fastpath.
+  t = absl::FromDateTime(-292091936940, kMin, kMin, kMin, kMin, kMin, utc);
+  EXPECT_EQ("Fri,  1 Nov -292277022657 10:37:52 +0000 (UTC)",
+            absl::FormatTime(fmt, t, utc));
+  t = absl::FromDateTime(-292091936941, kMin, kMin, kMin, kMin, kMin, utc);
+  EXPECT_EQ("infinite-past", absl::FormatTime(fmt, t, utc));  // no underflow
+  t = absl::FromDateTime(
+      std::numeric_limits<int64_t>::min(), kMin, kMin, kMin, kMin, kMin, utc);
+  EXPECT_EQ("infinite-past", absl::FormatTime(fmt, t, utc));  // no overflow
+
+  // Check that we're counting leap years correctly.
+  t = absl::FromDateTime(1900, 2, 28, 23, 59, 59, utc);
+  EXPECT_EQ("Wed, 28 Feb 1900 23:59:59 +0000 (UTC)",
+            absl::FormatTime(fmt, t, utc));
+  t = absl::FromDateTime(1900, 3, 1, 0, 0, 0, utc);
+  EXPECT_EQ("Thu,  1 Mar 1900 00:00:00 +0000 (UTC)",
+            absl::FormatTime(fmt, t, utc));
+  t = absl::FromDateTime(2000, 2, 29, 23, 59, 59, utc);
+  EXPECT_EQ("Tue, 29 Feb 2000 23:59:59 +0000 (UTC)",
+            absl::FormatTime(fmt, t, utc));
+  t = absl::FromDateTime(2000, 3, 1, 0, 0, 0, utc);
+  EXPECT_EQ("Wed,  1 Mar 2000 00:00:00 +0000 (UTC)",
+            absl::FormatTime(fmt, t, utc));
+
+  // Check normalization.
+  const std::string ymdhms = "%Y-%m-%d %H:%M:%S";
+  t = absl::FromDateTime(2015, 1, 1, 0, 0, 60, utc);
+  EXPECT_EQ("2015-01-01 00:01:00", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, 1, 1, 0, 60, 0, utc);
+  EXPECT_EQ("2015-01-01 01:00:00", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, 1, 1, 24, 0, 0, utc);
+  EXPECT_EQ("2015-01-02 00:00:00", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, 1, 32, 0, 0, 0, utc);
+  EXPECT_EQ("2015-02-01 00:00:00", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, 13, 1, 0, 0, 0, utc);
+  EXPECT_EQ("2016-01-01 00:00:00", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, 13, 32, 60, 60, 60, utc);
+  EXPECT_EQ("2016-02-03 13:01:00", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, 1, 1, 0, 0, -1, utc);
+  EXPECT_EQ("2014-12-31 23:59:59", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, 1, 1, 0, -1, 0, utc);
+  EXPECT_EQ("2014-12-31 23:59:00", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, 1, 1, -1, 0, 0, utc);
+  EXPECT_EQ("2014-12-31 23:00:00", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, 1, -1, 0, 0, 0, utc);
+  EXPECT_EQ("2014-12-30 00:00:00", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, -1, 1, 0, 0, 0, utc);
+  EXPECT_EQ("2014-11-01 00:00:00", absl::FormatTime(ymdhms, t, utc));
+  t = absl::FromDateTime(2015, -1, -1, -1, -1, -1, utc);
+  EXPECT_EQ("2014-10-29 22:58:59", absl::FormatTime(ymdhms, t, utc));
+}
+
+TEST(Time, ToTM) {
+  const absl::TimeZone utc = absl::UTCTimeZone();
+
+  // Compares the results of ToTM() to gmtime_r() for lots of times over the
+  // course of a few days.
+  const absl::Time start = absl::FromDateTime(2014, 1, 2, 3, 4, 5, utc);
+  const absl::Time end = absl::FromDateTime(2014, 1, 5, 3, 4, 5, utc);
+  for (absl::Time t = start; t < end; t += absl::Seconds(30)) {
+    const struct tm tm_bt = ToTM(t, utc);
+    const time_t tt = absl::ToTimeT(t);
+    struct tm tm_lc;
+#ifdef _WIN32
+    gmtime_s(&tm_lc, &tt);
+#else
+    gmtime_r(&tt, &tm_lc);
+#endif
+    EXPECT_EQ(tm_lc.tm_year, tm_bt.tm_year);
+    EXPECT_EQ(tm_lc.tm_mon, tm_bt.tm_mon);
+    EXPECT_EQ(tm_lc.tm_mday, tm_bt.tm_mday);
+    EXPECT_EQ(tm_lc.tm_hour, tm_bt.tm_hour);
+    EXPECT_EQ(tm_lc.tm_min, tm_bt.tm_min);
+    EXPECT_EQ(tm_lc.tm_sec, tm_bt.tm_sec);
+    EXPECT_EQ(tm_lc.tm_wday, tm_bt.tm_wday);
+    EXPECT_EQ(tm_lc.tm_yday, tm_bt.tm_yday);
+    EXPECT_EQ(tm_lc.tm_isdst, tm_bt.tm_isdst);
+
+    ASSERT_FALSE(HasFailure());
+  }
+
+  // Checks that the tm_isdst field is correct when in standard time.
+  const absl::TimeZone nyc =
+      absl::time_internal::LoadTimeZone("America/New_York");
+  absl::Time t = absl::FromDateTime(2014, 3, 1, 0, 0, 0, nyc);
+  struct tm tm = ToTM(t, nyc);
+  EXPECT_FALSE(tm.tm_isdst);
+
+  // Checks that the tm_isdst field is correct when in daylight time.
+  t = absl::FromDateTime(2014, 4, 1, 0, 0, 0, nyc);
+  tm = ToTM(t, nyc);
+  EXPECT_TRUE(tm.tm_isdst);
+
+  // Checks overflow.
+  tm = ToTM(absl::InfiniteFuture(), nyc);
+  EXPECT_EQ(std::numeric_limits<int>::max() - 1900, tm.tm_year);
+  EXPECT_EQ(11, tm.tm_mon);
+  EXPECT_EQ(31, tm.tm_mday);
+  EXPECT_EQ(23, tm.tm_hour);
+  EXPECT_EQ(59, tm.tm_min);
+  EXPECT_EQ(59, tm.tm_sec);
+  EXPECT_EQ(4, tm.tm_wday);
+  EXPECT_EQ(364, tm.tm_yday);
+  EXPECT_FALSE(tm.tm_isdst);
+
+  // Checks underflow.
+  tm = ToTM(absl::InfinitePast(), nyc);
+  EXPECT_EQ(std::numeric_limits<int>::min(), tm.tm_year);
+  EXPECT_EQ(0, tm.tm_mon);
+  EXPECT_EQ(1, tm.tm_mday);
+  EXPECT_EQ(0, tm.tm_hour);
+  EXPECT_EQ(0, tm.tm_min);
+  EXPECT_EQ(0, tm.tm_sec);
+  EXPECT_EQ(0, tm.tm_wday);
+  EXPECT_EQ(0, tm.tm_yday);
+  EXPECT_FALSE(tm.tm_isdst);
+}
+
+TEST(Time, FromTM) {
+  const absl::TimeZone nyc =
+      absl::time_internal::LoadTimeZone("America/New_York");
+
+  // Verifies that tm_isdst doesn't affect anything when the time is unique.
+  struct tm tm;
+  std::memset(&tm, 0, sizeof(tm));
+  tm.tm_year = 2014 - 1900;
+  tm.tm_mon = 6 - 1;
+  tm.tm_mday = 28;
+  tm.tm_hour = 1;
+  tm.tm_min = 2;
+  tm.tm_sec = 3;
+  tm.tm_isdst = -1;
+  absl::Time t = FromTM(tm, nyc);
+  EXPECT_EQ("2014-06-28T01:02:03-04:00", absl::FormatTime(t, nyc));  // DST
+  tm.tm_isdst = 0;
+  t = FromTM(tm, nyc);
+  EXPECT_EQ("2014-06-28T01:02:03-04:00", absl::FormatTime(t, nyc));  // DST
+  tm.tm_isdst = 1;
+  t = FromTM(tm, nyc);
+  EXPECT_EQ("2014-06-28T01:02:03-04:00", absl::FormatTime(t, nyc));  // DST
+
+  // Adjusts tm to refer to an ambiguous time.
+  tm.tm_year = 2014 - 1900;
+  tm.tm_mon = 11 - 1;
+  tm.tm_mday = 2;
+  tm.tm_hour = 1;
+  tm.tm_min = 30;
+  tm.tm_sec = 42;
+  tm.tm_isdst = -1;
+  t = FromTM(tm, nyc);
+  EXPECT_EQ("2014-11-02T01:30:42-04:00", absl::FormatTime(t, nyc));  // DST
+  tm.tm_isdst = 0;
+  t = FromTM(tm, nyc);
+  EXPECT_EQ("2014-11-02T01:30:42-05:00", absl::FormatTime(t, nyc));  // STD
+  tm.tm_isdst = 1;
+  t = FromTM(tm, nyc);
+  EXPECT_EQ("2014-11-02T01:30:42-04:00", absl::FormatTime(t, nyc));  // DST
+
+  // Adjusts tm to refer to a skipped time.
+  tm.tm_year = 2014 - 1900;
+  tm.tm_mon = 3 - 1;
+  tm.tm_mday = 9;
+  tm.tm_hour = 2;
+  tm.tm_min = 30;
+  tm.tm_sec = 42;
+  tm.tm_isdst = -1;
+  t = FromTM(tm, nyc);
+  EXPECT_EQ("2014-03-09T03:30:42-04:00", absl::FormatTime(t, nyc));  // DST
+  tm.tm_isdst = 0;
+  t = FromTM(tm, nyc);
+  EXPECT_EQ("2014-03-09T01:30:42-05:00", absl::FormatTime(t, nyc));  // STD
+  tm.tm_isdst = 1;
+  t = FromTM(tm, nyc);
+  EXPECT_EQ("2014-03-09T03:30:42-04:00", absl::FormatTime(t, nyc));  // DST
+}
+
+TEST(Time, TMRoundTrip) {
+  const absl::TimeZone nyc =
+      absl::time_internal::LoadTimeZone("America/New_York");
+
+  // Test round-tripping across a skipped transition
+  absl::Time start = absl::FromDateTime(2014, 3, 9, 0, 0, 0, nyc);
+  absl::Time end = absl::FromDateTime(2014, 3, 9, 4, 0, 0, nyc);
+  for (absl::Time t = start; t < end; t += absl::Minutes(1)) {
+    struct tm tm = ToTM(t, nyc);
+    absl::Time rt = FromTM(tm, nyc);
+    EXPECT_EQ(rt, t);
+  }
+
+  // Test round-tripping across an ambiguous transition
+  start = absl::FromDateTime(2014, 11, 2, 0, 0, 0, nyc);
+  end = absl::FromDateTime(2014, 11, 2, 4, 0, 0, nyc);
+  for (absl::Time t = start; t < end; t += absl::Minutes(1)) {
+    struct tm tm = ToTM(t, nyc);
+    absl::Time rt = FromTM(tm, nyc);
+    EXPECT_EQ(rt, t);
+  }
+
+  // Test round-tripping of unique instants crossing a day boundary
+  start = absl::FromDateTime(2014, 6, 27, 22, 0, 0, nyc);
+  end = absl::FromDateTime(2014, 6, 28, 4, 0, 0, nyc);
+  for (absl::Time t = start; t < end; t += absl::Minutes(1)) {
+    struct tm tm = ToTM(t, nyc);
+    absl::Time rt = FromTM(tm, nyc);
+    EXPECT_EQ(rt, t);
+  }
+}
+
+TEST(Time, Range) {
+  // The API's documented range is +/- 100 billion years.
+  const absl::Duration range = absl::Hours(24) * 365.2425 * 100000000000;
+
+  // Arithmetic and comparison still works at +/-range around base values.
+  absl::Time bases[2] = {absl::UnixEpoch(), absl::Now()};
+  for (const auto base : bases) {
+    absl::Time bottom = base - range;
+    EXPECT_GT(bottom, bottom - absl::Nanoseconds(1));
+    EXPECT_LT(bottom, bottom + absl::Nanoseconds(1));
+    absl::Time top = base + range;
+    EXPECT_GT(top, top - absl::Nanoseconds(1));
+    EXPECT_LT(top, top + absl::Nanoseconds(1));
+    absl::Duration full_range = 2 * range;
+    EXPECT_EQ(full_range, top - bottom);
+    EXPECT_EQ(-full_range, bottom - top);
+  }
+}
+
+TEST(Time, Limits) {
+  // It is an implementation detail that Time().rep_ == ZeroDuration(),
+  // and that the resolution of a Duration is 1/4 of a nanosecond.
+  const absl::Time zero;
+  const absl::Time max =
+      zero + absl::Seconds(std::numeric_limits<int64_t>::max()) +
+      absl::Nanoseconds(999999999) + absl::Nanoseconds(3) / 4;
+  const absl::Time min =
+      zero + absl::Seconds(std::numeric_limits<int64_t>::min());
+
+  // Some simple max/min bounds checks.
+  EXPECT_LT(max, absl::InfiniteFuture());
+  EXPECT_GT(min, absl::InfinitePast());
+  EXPECT_LT(zero, max);
+  EXPECT_GT(zero, min);
+  EXPECT_GE(absl::UnixEpoch(), min);
+  EXPECT_LT(absl::UnixEpoch(), max);
+
+  // Check sign of Time differences.
+  EXPECT_LT(absl::ZeroDuration(), max - zero);
+  EXPECT_LT(absl::ZeroDuration(),
+            zero - absl::Nanoseconds(1) / 4 - min);  // avoid zero - min
+
+  // Arithmetic works at max - 0.25ns and min + 0.25ns.
+  EXPECT_GT(max, max - absl::Nanoseconds(1) / 4);
+  EXPECT_LT(min, min + absl::Nanoseconds(1) / 4);
+}
+
+TEST(Time, ConversionSaturation) {
+  const absl::TimeZone utc = absl::UTCTimeZone();
+  absl::Time t;
+
+  const auto max_time_t = std::numeric_limits<time_t>::max();
+  const auto min_time_t = std::numeric_limits<time_t>::min();
+  time_t tt = max_time_t - 1;
+  t = absl::FromTimeT(tt);
+  tt = absl::ToTimeT(t);
+  EXPECT_EQ(max_time_t - 1, tt);
+  t += absl::Seconds(1);
+  tt = absl::ToTimeT(t);
+  EXPECT_EQ(max_time_t, tt);
+  t += absl::Seconds(1);  // no effect
+  tt = absl::ToTimeT(t);
+  EXPECT_EQ(max_time_t, tt);
+
+  tt = min_time_t + 1;
+  t = absl::FromTimeT(tt);
+  tt = absl::ToTimeT(t);
+  EXPECT_EQ(min_time_t + 1, tt);
+  t -= absl::Seconds(1);
+  tt = absl::ToTimeT(t);
+  EXPECT_EQ(min_time_t, tt);
+  t -= absl::Seconds(1);  // no effect
+  tt = absl::ToTimeT(t);
+  EXPECT_EQ(min_time_t, tt);
+
+  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;
+  t = absl::TimeFromTimeval(tv);
+  tv = ToTimeval(t);
+  EXPECT_EQ(max_timeval_sec, tv.tv_sec);
+  EXPECT_EQ(999998, tv.tv_usec);
+  t += absl::Microseconds(1);
+  tv = ToTimeval(t);
+  EXPECT_EQ(max_timeval_sec, tv.tv_sec);
+  EXPECT_EQ(999999, tv.tv_usec);
+  t += absl::Microseconds(1);  // no effect
+  tv = ToTimeval(t);
+  EXPECT_EQ(max_timeval_sec, tv.tv_sec);
+  EXPECT_EQ(999999, tv.tv_usec);
+
+  tv.tv_sec = min_timeval_sec;
+  tv.tv_usec = 1;
+  t = absl::TimeFromTimeval(tv);
+  tv = ToTimeval(t);
+  EXPECT_EQ(min_timeval_sec, tv.tv_sec);
+  EXPECT_EQ(1, tv.tv_usec);
+  t -= absl::Microseconds(1);
+  tv = ToTimeval(t);
+  EXPECT_EQ(min_timeval_sec, tv.tv_sec);
+  EXPECT_EQ(0, tv.tv_usec);
+  t -= absl::Microseconds(1);  // no effect
+  tv = ToTimeval(t);
+  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;
+  t = absl::TimeFromTimespec(ts);
+  ts = absl::ToTimespec(t);
+  EXPECT_EQ(max_timespec_sec, ts.tv_sec);
+  EXPECT_EQ(999999998, ts.tv_nsec);
+  t += absl::Nanoseconds(1);
+  ts = absl::ToTimespec(t);
+  EXPECT_EQ(max_timespec_sec, ts.tv_sec);
+  EXPECT_EQ(999999999, ts.tv_nsec);
+  t += absl::Nanoseconds(1);  // no effect
+  ts = absl::ToTimespec(t);
+  EXPECT_EQ(max_timespec_sec, ts.tv_sec);
+  EXPECT_EQ(999999999, ts.tv_nsec);
+
+  ts.tv_sec = min_timespec_sec;
+  ts.tv_nsec = 1;
+  t = absl::TimeFromTimespec(ts);
+  ts = absl::ToTimespec(t);
+  EXPECT_EQ(min_timespec_sec, ts.tv_sec);
+  EXPECT_EQ(1, ts.tv_nsec);
+  t -= absl::Nanoseconds(1);
+  ts = absl::ToTimespec(t);
+  EXPECT_EQ(min_timespec_sec, ts.tv_sec);
+  EXPECT_EQ(0, ts.tv_nsec);
+  t -= absl::Nanoseconds(1);  // no effect
+  ts = absl::ToTimespec(t);
+  EXPECT_EQ(min_timespec_sec, ts.tv_sec);
+  EXPECT_EQ(0, ts.tv_nsec);
+
+  // Checks how Time::In() saturates on infinities.
+  absl::Time::Breakdown bd = absl::InfiniteFuture().In(utc);
+  ABSL_INTERNAL_EXPECT_TIME(bd, std::numeric_limits<int64_t>::max(), 12, 31, 23,
+                            59, 59, 0, false, "-0000");
+  EXPECT_EQ(absl::InfiniteDuration(), bd.subsecond);
+  EXPECT_EQ(4, bd.weekday);  // Thursday
+  EXPECT_EQ(365, bd.yearday);
+  bd = absl::InfinitePast().In(utc);
+  ABSL_INTERNAL_EXPECT_TIME(bd, std::numeric_limits<int64_t>::min(), 1, 1, 0, 0,
+                            0, 0, false, "-0000");
+  EXPECT_EQ(-absl::InfiniteDuration(), bd.subsecond);
+  EXPECT_EQ(7, bd.weekday);  // Sunday
+  EXPECT_EQ(1, bd.yearday);
+
+  // Approach the maximal Time value from below.
+  t = absl::FromDateTime(292277026596, 12, 4, 15, 30, 6, utc);
+  EXPECT_EQ("292277026596-12-04T15:30:06+00:00",
+            absl::FormatTime(absl::RFC3339_full, t, utc));
+  t = absl::FromDateTime(292277026596, 12, 4, 15, 30, 7, utc);
+  EXPECT_EQ("292277026596-12-04T15:30:07+00:00",
+            absl::FormatTime(absl::RFC3339_full, t, utc));
+  EXPECT_EQ(
+      absl::UnixEpoch() + absl::Seconds(std::numeric_limits<int64_t>::max()), t);
+
+  // Checks that we can also get the maximal Time value for a far-east zone.
+  const absl::TimeZone plus14 = absl::FixedTimeZone(14 * 60 * 60);
+  t = absl::FromDateTime(292277026596, 12, 5, 5, 30, 7, plus14);
+  EXPECT_EQ("292277026596-12-05T05:30:07+14:00",
+            absl::FormatTime(absl::RFC3339_full, t, plus14));
+  EXPECT_EQ(
+      absl::UnixEpoch() + absl::Seconds(std::numeric_limits<int64_t>::max()), t);
+
+  // One second later should push us to infinity.
+  t = absl::FromDateTime(292277026596, 12, 4, 15, 30, 8, utc);
+  EXPECT_EQ("infinite-future", absl::FormatTime(absl::RFC3339_full, t, utc));
+
+  // Approach the minimal Time value from above.
+  t = absl::FromDateTime(-292277022657, 1, 27, 8, 29, 53, utc);
+  EXPECT_EQ("-292277022657-01-27T08:29:53+00:00",
+            absl::FormatTime(absl::RFC3339_full, t, utc));
+  t = absl::FromDateTime(-292277022657, 1, 27, 8, 29, 52, utc);
+  EXPECT_EQ("-292277022657-01-27T08:29:52+00:00",
+            absl::FormatTime(absl::RFC3339_full, t, utc));
+  EXPECT_EQ(
+      absl::UnixEpoch() + absl::Seconds(std::numeric_limits<int64_t>::min()), t);
+
+  // Checks that we can also get the minimal Time value for a far-west zone.
+  const absl::TimeZone minus12 = absl::FixedTimeZone(-12 * 60 * 60);
+  t = absl::FromDateTime(-292277022657, 1, 26, 20, 29, 52, minus12);
+  EXPECT_EQ("-292277022657-01-26T20:29:52-12:00",
+            absl::FormatTime(absl::RFC3339_full, t, minus12));
+  EXPECT_EQ(
+      absl::UnixEpoch() + absl::Seconds(std::numeric_limits<int64_t>::min()), t);
+
+  // One second before should push us to -infinity.
+  t = absl::FromDateTime(-292277022657, 1, 27, 8, 29, 51, utc);
+  EXPECT_EQ("infinite-past", absl::FormatTime(absl::RFC3339_full, t, utc));
+}
+
+// In zones with POSIX-style recurring rules we use special logic to
+// handle conversions in the distant future.  Here we check the limits
+// of those conversions, particularly with respect to integer overflow.
+TEST(Time, ExtendedConversionSaturation) {
+  const absl::TimeZone syd =
+      absl::time_internal::LoadTimeZone("Australia/Sydney");
+  const absl::TimeZone nyc =
+      absl::time_internal::LoadTimeZone("America/New_York");
+  const absl::Time max =
+      absl::FromUnixSeconds(std::numeric_limits<int64_t>::max());
+  absl::Time::Breakdown bd;
+  absl::Time t;
+
+  // The maximal time converted in each zone.
+  bd = max.In(syd);
+  ABSL_INTERNAL_EXPECT_TIME(bd, 292277026596, 12, 5, 2, 30, 7, 39600, true,
+                            "AEDT");
+  t = absl::FromDateTime(292277026596, 12, 5, 2, 30, 7, syd);
+  EXPECT_EQ(max, t);
+  bd = max.In(nyc);
+  ABSL_INTERNAL_EXPECT_TIME(bd, 292277026596, 12, 4, 10, 30, 7, -18000, false,
+                            "EST");
+  t = absl::FromDateTime(292277026596, 12, 4, 10, 30, 7, nyc);
+  EXPECT_EQ(max, t);
+
+  // One second later should push us to infinity.
+  t = absl::FromDateTime(292277026596, 12, 5, 2, 30, 8, syd);
+  EXPECT_EQ(absl::InfiniteFuture(), t);
+  t = absl::FromDateTime(292277026596, 12, 4, 10, 30, 8, nyc);
+  EXPECT_EQ(absl::InfiniteFuture(), t);
+
+  // And we should stick there.
+  t = absl::FromDateTime(292277026596, 12, 5, 2, 30, 9, syd);
+  EXPECT_EQ(absl::InfiniteFuture(), t);
+  t = absl::FromDateTime(292277026596, 12, 4, 10, 30, 9, nyc);
+  EXPECT_EQ(absl::InfiniteFuture(), t);
+
+  // All the way up to a saturated date/time, without overflow.
+  t = absl::FromDateTime(
+      std::numeric_limits<int64_t>::max(), 12, 31, 23, 59, 59, syd);
+  EXPECT_EQ(absl::InfiniteFuture(), t);
+  t = absl::FromDateTime(
+      std::numeric_limits<int64_t>::max(), 12, 31, 23, 59, 59, nyc);
+  EXPECT_EQ(absl::InfiniteFuture(), t);
+}
+
+}  // namespace