about summary refs log tree commit diff
path: root/third_party/abseil_cpp/absl/synchronization/mutex_test.cc
diff options
context:
space:
mode:
authorVincent Ambo <mail@tazj.in>2022-02-07T23·05+0300
committerclbot <clbot@tvl.fyi>2022-02-07T23·09+0000
commit5aa5d282eac56a21e74611c1cdbaa97bb5db2dca (patch)
tree8cc5dce8157a1470ff76719dd15d65f648a05522 /third_party/abseil_cpp/absl/synchronization/mutex_test.cc
parenta25675804c4f429fab5ee5201fe25e89865dfd13 (diff)
chore(3p/abseil_cpp): unvendor abseil_cpp r/3786
we weren't actually using these sources anymore, okay?

Change-Id: If701571d9716de308d3512e1eb22c35db0877a66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5248
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>
Diffstat (limited to 'third_party/abseil_cpp/absl/synchronization/mutex_test.cc')
-rw-r--r--third_party/abseil_cpp/absl/synchronization/mutex_test.cc1706
1 files changed, 0 insertions, 1706 deletions
diff --git a/third_party/abseil_cpp/absl/synchronization/mutex_test.cc b/third_party/abseil_cpp/absl/synchronization/mutex_test.cc
deleted file mode 100644
index 058f757b482f..000000000000
--- a/third_party/abseil_cpp/absl/synchronization/mutex_test.cc
+++ /dev/null
@@ -1,1706 +0,0 @@
-// 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
-//
-//      https://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/synchronization/mutex.h"
-
-#ifdef _WIN32
-#include <windows.h>
-#endif
-
-#include <algorithm>
-#include <atomic>
-#include <cstdlib>
-#include <functional>
-#include <memory>
-#include <random>
-#include <string>
-#include <thread>  // NOLINT(build/c++11)
-#include <vector>
-
-#include "gtest/gtest.h"
-#include "absl/base/attributes.h"
-#include "absl/base/config.h"
-#include "absl/base/internal/raw_logging.h"
-#include "absl/base/internal/sysinfo.h"
-#include "absl/memory/memory.h"
-#include "absl/synchronization/internal/thread_pool.h"
-#include "absl/time/clock.h"
-#include "absl/time/time.h"
-
-namespace {
-
-// TODO(dmauro): Replace with a commandline flag.
-static constexpr bool kExtendedTest = false;
-
-std::unique_ptr<absl::synchronization_internal::ThreadPool> CreatePool(
-    int threads) {
-  return absl::make_unique<absl::synchronization_internal::ThreadPool>(threads);
-}
-
-std::unique_ptr<absl::synchronization_internal::ThreadPool>
-CreateDefaultPool() {
-  return CreatePool(kExtendedTest ? 32 : 10);
-}
-
-// Hack to schedule a function to run on a thread pool thread after a
-// duration has elapsed.
-static void ScheduleAfter(absl::synchronization_internal::ThreadPool *tp,
-                          absl::Duration after,
-                          const std::function<void()> &func) {
-  tp->Schedule([func, after] {
-    absl::SleepFor(after);
-    func();
-  });
-}
-
-struct TestContext {
-  int iterations;
-  int threads;
-  int g0;  // global 0
-  int g1;  // global 1
-  absl::Mutex mu;
-  absl::CondVar cv;
-};
-
-// To test whether the invariant check call occurs
-static std::atomic<bool> invariant_checked;
-
-static bool GetInvariantChecked() {
-  return invariant_checked.load(std::memory_order_relaxed);
-}
-
-static void SetInvariantChecked(bool new_value) {
-  invariant_checked.store(new_value, std::memory_order_relaxed);
-}
-
-static void CheckSumG0G1(void *v) {
-  TestContext *cxt = static_cast<TestContext *>(v);
-  ABSL_RAW_CHECK(cxt->g0 == -cxt->g1, "Error in CheckSumG0G1");
-  SetInvariantChecked(true);
-}
-
-static void TestMu(TestContext *cxt, int c) {
-  for (int i = 0; i != cxt->iterations; i++) {
-    absl::MutexLock l(&cxt->mu);
-    int a = cxt->g0 + 1;
-    cxt->g0 = a;
-    cxt->g1--;
-  }
-}
-
-static void TestTry(TestContext *cxt, int c) {
-  for (int i = 0; i != cxt->iterations; i++) {
-    do {
-      std::this_thread::yield();
-    } while (!cxt->mu.TryLock());
-    int a = cxt->g0 + 1;
-    cxt->g0 = a;
-    cxt->g1--;
-    cxt->mu.Unlock();
-  }
-}
-
-static void TestR20ms(TestContext *cxt, int c) {
-  for (int i = 0; i != cxt->iterations; i++) {
-    absl::ReaderMutexLock l(&cxt->mu);
-    absl::SleepFor(absl::Milliseconds(20));
-    cxt->mu.AssertReaderHeld();
-  }
-}
-
-static void TestRW(TestContext *cxt, int c) {
-  if ((c & 1) == 0) {
-    for (int i = 0; i != cxt->iterations; i++) {
-      absl::WriterMutexLock l(&cxt->mu);
-      cxt->g0++;
-      cxt->g1--;
-      cxt->mu.AssertHeld();
-      cxt->mu.AssertReaderHeld();
-    }
-  } else {
-    for (int i = 0; i != cxt->iterations; i++) {
-      absl::ReaderMutexLock l(&cxt->mu);
-      ABSL_RAW_CHECK(cxt->g0 == -cxt->g1, "Error in TestRW");
-      cxt->mu.AssertReaderHeld();
-    }
-  }
-}
-
-struct MyContext {
-  int target;
-  TestContext *cxt;
-  bool MyTurn();
-};
-
-bool MyContext::MyTurn() {
-  TestContext *cxt = this->cxt;
-  return cxt->g0 == this->target || cxt->g0 == cxt->iterations;
-}
-
-static void TestAwait(TestContext *cxt, int c) {
-  MyContext mc;
-  mc.target = c;
-  mc.cxt = cxt;
-  absl::MutexLock l(&cxt->mu);
-  cxt->mu.AssertHeld();
-  while (cxt->g0 < cxt->iterations) {
-    cxt->mu.Await(absl::Condition(&mc, &MyContext::MyTurn));
-    ABSL_RAW_CHECK(mc.MyTurn(), "Error in TestAwait");
-    cxt->mu.AssertHeld();
-    if (cxt->g0 < cxt->iterations) {
-      int a = cxt->g0 + 1;
-      cxt->g0 = a;
-      mc.target += cxt->threads;
-    }
-  }
-}
-
-static void TestSignalAll(TestContext *cxt, int c) {
-  int target = c;
-  absl::MutexLock l(&cxt->mu);
-  cxt->mu.AssertHeld();
-  while (cxt->g0 < cxt->iterations) {
-    while (cxt->g0 != target && cxt->g0 != cxt->iterations) {
-      cxt->cv.Wait(&cxt->mu);
-    }
-    if (cxt->g0 < cxt->iterations) {
-      int a = cxt->g0 + 1;
-      cxt->g0 = a;
-      cxt->cv.SignalAll();
-      target += cxt->threads;
-    }
-  }
-}
-
-static void TestSignal(TestContext *cxt, int c) {
-  ABSL_RAW_CHECK(cxt->threads == 2, "TestSignal should use 2 threads");
-  int target = c;
-  absl::MutexLock l(&cxt->mu);
-  cxt->mu.AssertHeld();
-  while (cxt->g0 < cxt->iterations) {
-    while (cxt->g0 != target && cxt->g0 != cxt->iterations) {
-      cxt->cv.Wait(&cxt->mu);
-    }
-    if (cxt->g0 < cxt->iterations) {
-      int a = cxt->g0 + 1;
-      cxt->g0 = a;
-      cxt->cv.Signal();
-      target += cxt->threads;
-    }
-  }
-}
-
-static void TestCVTimeout(TestContext *cxt, int c) {
-  int target = c;
-  absl::MutexLock l(&cxt->mu);
-  cxt->mu.AssertHeld();
-  while (cxt->g0 < cxt->iterations) {
-    while (cxt->g0 != target && cxt->g0 != cxt->iterations) {
-      cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(100));
-    }
-    if (cxt->g0 < cxt->iterations) {
-      int a = cxt->g0 + 1;
-      cxt->g0 = a;
-      cxt->cv.SignalAll();
-      target += cxt->threads;
-    }
-  }
-}
-
-static bool G0GE2(TestContext *cxt) { return cxt->g0 >= 2; }
-
-static void TestTime(TestContext *cxt, int c, bool use_cv) {
-  ABSL_RAW_CHECK(cxt->iterations == 1, "TestTime should only use 1 iteration");
-  ABSL_RAW_CHECK(cxt->threads > 2, "TestTime should use more than 2 threads");
-  const bool kFalse = false;
-  absl::Condition false_cond(&kFalse);
-  absl::Condition g0ge2(G0GE2, cxt);
-  if (c == 0) {
-    absl::MutexLock l(&cxt->mu);
-
-    absl::Time start = absl::Now();
-    if (use_cv) {
-      cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(1));
-    } else {
-      ABSL_RAW_CHECK(!cxt->mu.AwaitWithTimeout(false_cond, absl::Seconds(1)),
-                     "TestTime failed");
-    }
-    absl::Duration elapsed = absl::Now() - start;
-    ABSL_RAW_CHECK(
-        absl::Seconds(0.9) <= elapsed && elapsed <= absl::Seconds(2.0),
-        "TestTime failed");
-    ABSL_RAW_CHECK(cxt->g0 == 1, "TestTime failed");
-
-    start = absl::Now();
-    if (use_cv) {
-      cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(1));
-    } else {
-      ABSL_RAW_CHECK(!cxt->mu.AwaitWithTimeout(false_cond, absl::Seconds(1)),
-                     "TestTime failed");
-    }
-    elapsed = absl::Now() - start;
-    ABSL_RAW_CHECK(
-        absl::Seconds(0.9) <= elapsed && elapsed <= absl::Seconds(2.0),
-        "TestTime failed");
-    cxt->g0++;
-    if (use_cv) {
-      cxt->cv.Signal();
-    }
-
-    start = absl::Now();
-    if (use_cv) {
-      cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(4));
-    } else {
-      ABSL_RAW_CHECK(!cxt->mu.AwaitWithTimeout(false_cond, absl::Seconds(4)),
-                     "TestTime failed");
-    }
-    elapsed = absl::Now() - start;
-    ABSL_RAW_CHECK(
-        absl::Seconds(3.9) <= elapsed && elapsed <= absl::Seconds(6.0),
-        "TestTime failed");
-    ABSL_RAW_CHECK(cxt->g0 >= 3, "TestTime failed");
-
-    start = absl::Now();
-    if (use_cv) {
-      cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(1));
-    } else {
-      ABSL_RAW_CHECK(!cxt->mu.AwaitWithTimeout(false_cond, absl::Seconds(1)),
-                     "TestTime failed");
-    }
-    elapsed = absl::Now() - start;
-    ABSL_RAW_CHECK(
-        absl::Seconds(0.9) <= elapsed && elapsed <= absl::Seconds(2.0),
-        "TestTime failed");
-    if (use_cv) {
-      cxt->cv.SignalAll();
-    }
-
-    start = absl::Now();
-    if (use_cv) {
-      cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(1));
-    } else {
-      ABSL_RAW_CHECK(!cxt->mu.AwaitWithTimeout(false_cond, absl::Seconds(1)),
-                     "TestTime failed");
-    }
-    elapsed = absl::Now() - start;
-    ABSL_RAW_CHECK(absl::Seconds(0.9) <= elapsed &&
-                   elapsed <= absl::Seconds(2.0), "TestTime failed");
-    ABSL_RAW_CHECK(cxt->g0 == cxt->threads, "TestTime failed");
-
-  } else if (c == 1) {
-    absl::MutexLock l(&cxt->mu);
-    const absl::Time start = absl::Now();
-    if (use_cv) {
-      cxt->cv.WaitWithTimeout(&cxt->mu, absl::Milliseconds(500));
-    } else {
-      ABSL_RAW_CHECK(
-          !cxt->mu.AwaitWithTimeout(false_cond, absl::Milliseconds(500)),
-          "TestTime failed");
-    }
-    const absl::Duration elapsed = absl::Now() - start;
-    ABSL_RAW_CHECK(
-        absl::Seconds(0.4) <= elapsed && elapsed <= absl::Seconds(0.9),
-        "TestTime failed");
-    cxt->g0++;
-  } else if (c == 2) {
-    absl::MutexLock l(&cxt->mu);
-    if (use_cv) {
-      while (cxt->g0 < 2) {
-        cxt->cv.WaitWithTimeout(&cxt->mu, absl::Seconds(100));
-      }
-    } else {
-      ABSL_RAW_CHECK(cxt->mu.AwaitWithTimeout(g0ge2, absl::Seconds(100)),
-                     "TestTime failed");
-    }
-    cxt->g0++;
-  } else {
-    absl::MutexLock l(&cxt->mu);
-    if (use_cv) {
-      while (cxt->g0 < 2) {
-        cxt->cv.Wait(&cxt->mu);
-      }
-    } else {
-      cxt->mu.Await(g0ge2);
-    }
-    cxt->g0++;
-  }
-}
-
-static void TestMuTime(TestContext *cxt, int c) { TestTime(cxt, c, false); }
-
-static void TestCVTime(TestContext *cxt, int c) { TestTime(cxt, c, true); }
-
-static void EndTest(int *c0, int *c1, absl::Mutex *mu, absl::CondVar *cv,
-                    const std::function<void(int)>& cb) {
-  mu->Lock();
-  int c = (*c0)++;
-  mu->Unlock();
-  cb(c);
-  absl::MutexLock l(mu);
-  (*c1)++;
-  cv->Signal();
-}
-
-// Code common to RunTest() and RunTestWithInvariantDebugging().
-static int RunTestCommon(TestContext *cxt, void (*test)(TestContext *cxt, int),
-                         int threads, int iterations, int operations) {
-  absl::Mutex mu2;
-  absl::CondVar cv2;
-  int c0 = 0;
-  int c1 = 0;
-  cxt->g0 = 0;
-  cxt->g1 = 0;
-  cxt->iterations = iterations;
-  cxt->threads = threads;
-  absl::synchronization_internal::ThreadPool tp(threads);
-  for (int i = 0; i != threads; i++) {
-    tp.Schedule(std::bind(&EndTest, &c0, &c1, &mu2, &cv2,
-                          std::function<void(int)>(
-                              std::bind(test, cxt, std::placeholders::_1))));
-  }
-  mu2.Lock();
-  while (c1 != threads) {
-    cv2.Wait(&mu2);
-  }
-  mu2.Unlock();
-  return cxt->g0;
-}
-
-// Basis for the parameterized tests configured below.
-static int RunTest(void (*test)(TestContext *cxt, int), int threads,
-                   int iterations, int operations) {
-  TestContext cxt;
-  return RunTestCommon(&cxt, test, threads, iterations, operations);
-}
-
-// Like RunTest(), but sets an invariant on the tested Mutex and
-// verifies that the invariant check happened. The invariant function
-// will be passed the TestContext* as its arg and must call
-// SetInvariantChecked(true);
-#if !defined(ABSL_MUTEX_ENABLE_INVARIANT_DEBUGGING_NOT_IMPLEMENTED)
-static int RunTestWithInvariantDebugging(void (*test)(TestContext *cxt, int),
-                                         int threads, int iterations,
-                                         int operations,
-                                         void (*invariant)(void *)) {
-  absl::EnableMutexInvariantDebugging(true);
-  SetInvariantChecked(false);
-  TestContext cxt;
-  cxt.mu.EnableInvariantDebugging(invariant, &cxt);
-  int ret = RunTestCommon(&cxt, test, threads, iterations, operations);
-  ABSL_RAW_CHECK(GetInvariantChecked(), "Invariant not checked");
-  absl::EnableMutexInvariantDebugging(false);  // Restore.
-  return ret;
-}
-#endif
-
-// --------------------------------------------------------
-// Test for fix of bug in TryRemove()
-struct TimeoutBugStruct {
-  absl::Mutex mu;
-  bool a;
-  int a_waiter_count;
-};
-
-static void WaitForA(TimeoutBugStruct *x) {
-  x->mu.LockWhen(absl::Condition(&x->a));
-  x->a_waiter_count--;
-  x->mu.Unlock();
-}
-
-static bool NoAWaiters(TimeoutBugStruct *x) { return x->a_waiter_count == 0; }
-
-// Test that a CondVar.Wait(&mutex) can un-block a call to mutex.Await() in
-// another thread.
-TEST(Mutex, CondVarWaitSignalsAwait) {
-  // Use a struct so the lock annotations apply.
-  struct {
-    absl::Mutex barrier_mu;
-    bool barrier ABSL_GUARDED_BY(barrier_mu) = false;
-
-    absl::Mutex release_mu;
-    bool release ABSL_GUARDED_BY(release_mu) = false;
-    absl::CondVar released_cv;
-  } state;
-
-  auto pool = CreateDefaultPool();
-
-  // Thread A.  Sets barrier, waits for release using Mutex::Await, then
-  // signals released_cv.
-  pool->Schedule([&state] {
-    state.release_mu.Lock();
-
-    state.barrier_mu.Lock();
-    state.barrier = true;
-    state.barrier_mu.Unlock();
-
-    state.release_mu.Await(absl::Condition(&state.release));
-    state.released_cv.Signal();
-    state.release_mu.Unlock();
-  });
-
-  state.barrier_mu.LockWhen(absl::Condition(&state.barrier));
-  state.barrier_mu.Unlock();
-  state.release_mu.Lock();
-  // Thread A is now blocked on release by way of Mutex::Await().
-
-  // Set release.  Calling released_cv.Wait() should un-block thread A,
-  // which will signal released_cv.  If not, the test will hang.
-  state.release = true;
-  state.released_cv.Wait(&state.release_mu);
-  state.release_mu.Unlock();
-}
-
-// Test that a CondVar.WaitWithTimeout(&mutex) can un-block a call to
-// mutex.Await() in another thread.
-TEST(Mutex, CondVarWaitWithTimeoutSignalsAwait) {
-  // Use a struct so the lock annotations apply.
-  struct {
-    absl::Mutex barrier_mu;
-    bool barrier ABSL_GUARDED_BY(barrier_mu) = false;
-
-    absl::Mutex release_mu;
-    bool release ABSL_GUARDED_BY(release_mu) = false;
-    absl::CondVar released_cv;
-  } state;
-
-  auto pool = CreateDefaultPool();
-
-  // Thread A.  Sets barrier, waits for release using Mutex::Await, then
-  // signals released_cv.
-  pool->Schedule([&state] {
-    state.release_mu.Lock();
-
-    state.barrier_mu.Lock();
-    state.barrier = true;
-    state.barrier_mu.Unlock();
-
-    state.release_mu.Await(absl::Condition(&state.release));
-    state.released_cv.Signal();
-    state.release_mu.Unlock();
-  });
-
-  state.barrier_mu.LockWhen(absl::Condition(&state.barrier));
-  state.barrier_mu.Unlock();
-  state.release_mu.Lock();
-  // Thread A is now blocked on release by way of Mutex::Await().
-
-  // Set release.  Calling released_cv.Wait() should un-block thread A,
-  // which will signal released_cv.  If not, the test will hang.
-  state.release = true;
-  EXPECT_TRUE(
-      !state.released_cv.WaitWithTimeout(&state.release_mu, absl::Seconds(10)))
-      << "; Unrecoverable test failure: CondVar::WaitWithTimeout did not "
-         "unblock the absl::Mutex::Await call in another thread.";
-
-  state.release_mu.Unlock();
-}
-
-// Test for regression of a bug in loop of TryRemove()
-TEST(Mutex, MutexTimeoutBug) {
-  auto tp = CreateDefaultPool();
-
-  TimeoutBugStruct x;
-  x.a = false;
-  x.a_waiter_count = 2;
-  tp->Schedule(std::bind(&WaitForA, &x));
-  tp->Schedule(std::bind(&WaitForA, &x));
-  absl::SleepFor(absl::Seconds(1));  // Allow first two threads to hang.
-  // The skip field of the second will point to the first because there are
-  // only two.
-
-  // Now cause a thread waiting on an always-false to time out
-  // This would deadlock when the bug was present.
-  bool always_false = false;
-  x.mu.LockWhenWithTimeout(absl::Condition(&always_false),
-                           absl::Milliseconds(500));
-
-  // if we get here, the bug is not present.   Cleanup the state.
-
-  x.a = true;                                    // wakeup the two waiters on A
-  x.mu.Await(absl::Condition(&NoAWaiters, &x));  // wait for them to exit
-  x.mu.Unlock();
-}
-
-struct CondVarWaitDeadlock : testing::TestWithParam<int> {
-  absl::Mutex mu;
-  absl::CondVar cv;
-  bool cond1 = false;
-  bool cond2 = false;
-  bool read_lock1;
-  bool read_lock2;
-  bool signal_unlocked;
-
-  CondVarWaitDeadlock() {
-    read_lock1 = GetParam() & (1 << 0);
-    read_lock2 = GetParam() & (1 << 1);
-    signal_unlocked = GetParam() & (1 << 2);
-  }
-
-  void Waiter1() {
-    if (read_lock1) {
-      mu.ReaderLock();
-      while (!cond1) {
-        cv.Wait(&mu);
-      }
-      mu.ReaderUnlock();
-    } else {
-      mu.Lock();
-      while (!cond1) {
-        cv.Wait(&mu);
-      }
-      mu.Unlock();
-    }
-  }
-
-  void Waiter2() {
-    if (read_lock2) {
-      mu.ReaderLockWhen(absl::Condition(&cond2));
-      mu.ReaderUnlock();
-    } else {
-      mu.LockWhen(absl::Condition(&cond2));
-      mu.Unlock();
-    }
-  }
-};
-
-// Test for a deadlock bug in Mutex::Fer().
-// The sequence of events that lead to the deadlock is:
-// 1. waiter1 blocks on cv in read mode (mu bits = 0).
-// 2. waiter2 blocks on mu in either mode (mu bits = kMuWait).
-// 3. main thread locks mu, sets cond1, unlocks mu (mu bits = kMuWait).
-// 4. main thread signals on cv and this eventually calls Mutex::Fer().
-// Currently Fer wakes waiter1 since mu bits = kMuWait (mutex is unlocked).
-// Before the bug fix Fer neither woke waiter1 nor queued it on mutex,
-// which resulted in deadlock.
-TEST_P(CondVarWaitDeadlock, Test) {
-  auto waiter1 = CreatePool(1);
-  auto waiter2 = CreatePool(1);
-  waiter1->Schedule([this] { this->Waiter1(); });
-  waiter2->Schedule([this] { this->Waiter2(); });
-
-  // Wait while threads block (best-effort is fine).
-  absl::SleepFor(absl::Milliseconds(100));
-
-  // Wake condwaiter.
-  mu.Lock();
-  cond1 = true;
-  if (signal_unlocked) {
-    mu.Unlock();
-    cv.Signal();
-  } else {
-    cv.Signal();
-    mu.Unlock();
-  }
-  waiter1.reset();  // "join" waiter1
-
-  // Wake waiter.
-  mu.Lock();
-  cond2 = true;
-  mu.Unlock();
-  waiter2.reset();  // "join" waiter2
-}
-
-INSTANTIATE_TEST_SUITE_P(CondVarWaitDeadlockTest, CondVarWaitDeadlock,
-                         ::testing::Range(0, 8),
-                         ::testing::PrintToStringParamName());
-
-// --------------------------------------------------------
-// Test for fix of bug in DequeueAllWakeable()
-// Bug was that if there was more than one waiting reader
-// and all should be woken, the most recently blocked one
-// would not be.
-
-struct DequeueAllWakeableBugStruct {
-  absl::Mutex mu;
-  absl::Mutex mu2;       // protects all fields below
-  int unfinished_count;  // count of unfinished readers; under mu2
-  bool done1;            // unfinished_count == 0; under mu2
-  int finished_count;    // count of finished readers, under mu2
-  bool done2;            // finished_count == 0; under mu2
-};
-
-// Test for regression of a bug in loop of DequeueAllWakeable()
-static void AcquireAsReader(DequeueAllWakeableBugStruct *x) {
-  x->mu.ReaderLock();
-  x->mu2.Lock();
-  x->unfinished_count--;
-  x->done1 = (x->unfinished_count == 0);
-  x->mu2.Unlock();
-  // make sure that both readers acquired mu before we release it.
-  absl::SleepFor(absl::Seconds(2));
-  x->mu.ReaderUnlock();
-
-  x->mu2.Lock();
-  x->finished_count--;
-  x->done2 = (x->finished_count == 0);
-  x->mu2.Unlock();
-}
-
-// Test for regression of a bug in loop of DequeueAllWakeable()
-TEST(Mutex, MutexReaderWakeupBug) {
-  auto tp = CreateDefaultPool();
-
-  DequeueAllWakeableBugStruct x;
-  x.unfinished_count = 2;
-  x.done1 = false;
-  x.finished_count = 2;
-  x.done2 = false;
-  x.mu.Lock();  // acquire mu exclusively
-  // queue two thread that will block on reader locks on x.mu
-  tp->Schedule(std::bind(&AcquireAsReader, &x));
-  tp->Schedule(std::bind(&AcquireAsReader, &x));
-  absl::SleepFor(absl::Seconds(1));  // give time for reader threads to block
-  x.mu.Unlock();                     // wake them up
-
-  // both readers should finish promptly
-  EXPECT_TRUE(
-      x.mu2.LockWhenWithTimeout(absl::Condition(&x.done1), absl::Seconds(10)));
-  x.mu2.Unlock();
-
-  EXPECT_TRUE(
-      x.mu2.LockWhenWithTimeout(absl::Condition(&x.done2), absl::Seconds(10)));
-  x.mu2.Unlock();
-}
-
-struct LockWhenTestStruct {
-  absl::Mutex mu1;
-  bool cond = false;
-
-  absl::Mutex mu2;
-  bool waiting = false;
-};
-
-static bool LockWhenTestIsCond(LockWhenTestStruct* s) {
-  s->mu2.Lock();
-  s->waiting = true;
-  s->mu2.Unlock();
-  return s->cond;
-}
-
-static void LockWhenTestWaitForIsCond(LockWhenTestStruct* s) {
-  s->mu1.LockWhen(absl::Condition(&LockWhenTestIsCond, s));
-  s->mu1.Unlock();
-}
-
-TEST(Mutex, LockWhen) {
-  LockWhenTestStruct s;
-
-  std::thread t(LockWhenTestWaitForIsCond, &s);
-  s.mu2.LockWhen(absl::Condition(&s.waiting));
-  s.mu2.Unlock();
-
-  s.mu1.Lock();
-  s.cond = true;
-  s.mu1.Unlock();
-
-  t.join();
-}
-
-TEST(Mutex, LockWhenGuard) {
-  absl::Mutex mu;
-  int n = 30;
-  bool done = false;
-
-  // We don't inline the lambda because the conversion is ambiguous in MSVC.
-  bool (*cond_eq_10)(int *) = [](int *p) { return *p == 10; };
-  bool (*cond_lt_10)(int *) = [](int *p) { return *p < 10; };
-
-  std::thread t1([&mu, &n, &done, cond_eq_10]() {
-    absl::ReaderMutexLock lock(&mu, absl::Condition(cond_eq_10, &n));
-    done = true;
-  });
-
-  std::thread t2[10];
-  for (std::thread &t : t2) {
-    t = std::thread([&mu, &n, cond_lt_10]() {
-      absl::WriterMutexLock lock(&mu, absl::Condition(cond_lt_10, &n));
-      ++n;
-    });
-  }
-
-  {
-    absl::MutexLock lock(&mu);
-    n = 0;
-  }
-
-  for (std::thread &t : t2) t.join();
-  t1.join();
-
-  EXPECT_TRUE(done);
-  EXPECT_EQ(n, 10);
-}
-
-// --------------------------------------------------------
-// The following test requires Mutex::ReaderLock to be a real shared
-// lock, which is not the case in all builds.
-#if !defined(ABSL_MUTEX_READER_LOCK_IS_EXCLUSIVE)
-
-// Test for fix of bug in UnlockSlow() that incorrectly decremented the reader
-// count when putting a thread to sleep waiting for a false condition when the
-// lock was not held.
-
-// For this bug to strike, we make a thread wait on a free mutex with no
-// waiters by causing its wakeup condition to be false.   Then the
-// next two acquirers must be readers.   The bug causes the lock
-// to be released when one reader unlocks, rather than both.
-
-struct ReaderDecrementBugStruct {
-  bool cond;  // to delay first thread (under mu)
-  int done;   // reference count (under mu)
-  absl::Mutex mu;
-
-  bool waiting_on_cond;   // under mu2
-  bool have_reader_lock;  // under mu2
-  bool complete;          // under mu2
-  absl::Mutex mu2;        // > mu
-};
-
-// L >= mu, L < mu_waiting_on_cond
-static bool IsCond(void *v) {
-  ReaderDecrementBugStruct *x = reinterpret_cast<ReaderDecrementBugStruct *>(v);
-  x->mu2.Lock();
-  x->waiting_on_cond = true;
-  x->mu2.Unlock();
-  return x->cond;
-}
-
-// L >= mu
-static bool AllDone(void *v) {
-  ReaderDecrementBugStruct *x = reinterpret_cast<ReaderDecrementBugStruct *>(v);
-  return x->done == 0;
-}
-
-// L={}
-static void WaitForCond(ReaderDecrementBugStruct *x) {
-  absl::Mutex dummy;
-  absl::MutexLock l(&dummy);
-  x->mu.LockWhen(absl::Condition(&IsCond, x));
-  x->done--;
-  x->mu.Unlock();
-}
-
-// L={}
-static void GetReadLock(ReaderDecrementBugStruct *x) {
-  x->mu.ReaderLock();
-  x->mu2.Lock();
-  x->have_reader_lock = true;
-  x->mu2.Await(absl::Condition(&x->complete));
-  x->mu2.Unlock();
-  x->mu.ReaderUnlock();
-  x->mu.Lock();
-  x->done--;
-  x->mu.Unlock();
-}
-
-// Test for reader counter being decremented incorrectly by waiter
-// with false condition.
-TEST(Mutex, MutexReaderDecrementBug) ABSL_NO_THREAD_SAFETY_ANALYSIS {
-  ReaderDecrementBugStruct x;
-  x.cond = false;
-  x.waiting_on_cond = false;
-  x.have_reader_lock = false;
-  x.complete = false;
-  x.done = 2;  // initial ref count
-
-  // Run WaitForCond() and wait for it to sleep
-  std::thread thread1(WaitForCond, &x);
-  x.mu2.LockWhen(absl::Condition(&x.waiting_on_cond));
-  x.mu2.Unlock();
-
-  // Run GetReadLock(), and wait for it to get the read lock
-  std::thread thread2(GetReadLock, &x);
-  x.mu2.LockWhen(absl::Condition(&x.have_reader_lock));
-  x.mu2.Unlock();
-
-  // Get the reader lock ourselves, and release it.
-  x.mu.ReaderLock();
-  x.mu.ReaderUnlock();
-
-  // The lock should be held in read mode by GetReadLock().
-  // If we have the bug, the lock will be free.
-  x.mu.AssertReaderHeld();
-
-  // Wake up all the threads.
-  x.mu2.Lock();
-  x.complete = true;
-  x.mu2.Unlock();
-
-  // TODO(delesley): turn on analysis once lock upgrading is supported.
-  // (This call upgrades the lock from shared to exclusive.)
-  x.mu.Lock();
-  x.cond = true;
-  x.mu.Await(absl::Condition(&AllDone, &x));
-  x.mu.Unlock();
-
-  thread1.join();
-  thread2.join();
-}
-#endif  // !ABSL_MUTEX_READER_LOCK_IS_EXCLUSIVE
-
-// Test that we correctly handle the situation when a lock is
-// held and then destroyed (w/o unlocking).
-#ifdef ABSL_HAVE_THREAD_SANITIZER
-// TSAN reports errors when locked Mutexes are destroyed.
-TEST(Mutex, DISABLED_LockedMutexDestructionBug) NO_THREAD_SAFETY_ANALYSIS {
-#else
-TEST(Mutex, LockedMutexDestructionBug) ABSL_NO_THREAD_SAFETY_ANALYSIS {
-#endif
-  for (int i = 0; i != 10; i++) {
-    // Create, lock and destroy 10 locks.
-    const int kNumLocks = 10;
-    auto mu = absl::make_unique<absl::Mutex[]>(kNumLocks);
-    for (int j = 0; j != kNumLocks; j++) {
-      if ((j % 2) == 0) {
-        mu[j].WriterLock();
-      } else {
-        mu[j].ReaderLock();
-      }
-    }
-  }
-}
-
-// --------------------------------------------------------
-// Test for bug with pattern of readers using a condvar.  The bug was that if a
-// reader went to sleep on a condition variable while one or more other readers
-// held the lock, but there were no waiters, the reader count (held in the
-// mutex word) would be lost.  (This is because Enqueue() had at one time
-// always placed the thread on the Mutex queue.  Later (CL 4075610), to
-// tolerate re-entry into Mutex from a Condition predicate, Enqueue() was
-// changed so that it could also place a thread on a condition-variable.  This
-// introduced the case where Enqueue() returned with an empty queue, and this
-// case was handled incorrectly in one place.)
-
-static void ReaderForReaderOnCondVar(absl::Mutex *mu, absl::CondVar *cv,
-                                     int *running) {
-  std::random_device dev;
-  std::mt19937 gen(dev());
-  std::uniform_int_distribution<int> random_millis(0, 15);
-  mu->ReaderLock();
-  while (*running == 3) {
-    absl::SleepFor(absl::Milliseconds(random_millis(gen)));
-    cv->WaitWithTimeout(mu, absl::Milliseconds(random_millis(gen)));
-  }
-  mu->ReaderUnlock();
-  mu->Lock();
-  (*running)--;
-  mu->Unlock();
-}
-
-struct True {
-  template <class... Args>
-  bool operator()(Args...) const {
-    return true;
-  }
-};
-
-struct DerivedTrue : True {};
-
-TEST(Mutex, FunctorCondition) {
-  {  // Variadic
-    True f;
-    EXPECT_TRUE(absl::Condition(&f).Eval());
-  }
-
-  {  // Inherited
-    DerivedTrue g;
-    EXPECT_TRUE(absl::Condition(&g).Eval());
-  }
-
-  {  // lambda
-    int value = 3;
-    auto is_zero = [&value] { return value == 0; };
-    absl::Condition c(&is_zero);
-    EXPECT_FALSE(c.Eval());
-    value = 0;
-    EXPECT_TRUE(c.Eval());
-  }
-
-  {  // bind
-    int value = 0;
-    auto is_positive = std::bind(std::less<int>(), 0, std::cref(value));
-    absl::Condition c(&is_positive);
-    EXPECT_FALSE(c.Eval());
-    value = 1;
-    EXPECT_TRUE(c.Eval());
-  }
-
-  {  // std::function
-    int value = 3;
-    std::function<bool()> is_zero = [&value] { return value == 0; };
-    absl::Condition c(&is_zero);
-    EXPECT_FALSE(c.Eval());
-    value = 0;
-    EXPECT_TRUE(c.Eval());
-  }
-}
-
-static bool IntIsZero(int *x) { return *x == 0; }
-
-// Test for reader waiting condition variable when there are other readers
-// but no waiters.
-TEST(Mutex, TestReaderOnCondVar) {
-  auto tp = CreateDefaultPool();
-  absl::Mutex mu;
-  absl::CondVar cv;
-  int running = 3;
-  tp->Schedule(std::bind(&ReaderForReaderOnCondVar, &mu, &cv, &running));
-  tp->Schedule(std::bind(&ReaderForReaderOnCondVar, &mu, &cv, &running));
-  absl::SleepFor(absl::Seconds(2));
-  mu.Lock();
-  running--;
-  mu.Await(absl::Condition(&IntIsZero, &running));
-  mu.Unlock();
-}
-
-// --------------------------------------------------------
-struct AcquireFromConditionStruct {
-  absl::Mutex mu0;   // protects value, done
-  int value;         // times condition function is called; under mu0,
-  bool done;         // done with test?  under mu0
-  absl::Mutex mu1;   // used to attempt to mess up state of mu0
-  absl::CondVar cv;  // so the condition function can be invoked from
-                     // CondVar::Wait().
-};
-
-static bool ConditionWithAcquire(AcquireFromConditionStruct *x) {
-  x->value++;  // count times this function is called
-
-  if (x->value == 2 || x->value == 3) {
-    // On the second and third invocation of this function, sleep for 100ms,
-    // but with the side-effect of altering the state of a Mutex other than
-    // than one for which this is a condition.  The spec now explicitly allows
-    // this side effect; previously it did not.  it was illegal.
-    bool always_false = false;
-    x->mu1.LockWhenWithTimeout(absl::Condition(&always_false),
-                               absl::Milliseconds(100));
-    x->mu1.Unlock();
-  }
-  ABSL_RAW_CHECK(x->value < 4, "should not be invoked a fourth time");
-
-  // We arrange for the condition to return true on only the 2nd and 3rd calls.
-  return x->value == 2 || x->value == 3;
-}
-
-static void WaitForCond2(AcquireFromConditionStruct *x) {
-  // wait for cond0 to become true
-  x->mu0.LockWhen(absl::Condition(&ConditionWithAcquire, x));
-  x->done = true;
-  x->mu0.Unlock();
-}
-
-// Test for Condition whose function acquires other Mutexes
-TEST(Mutex, AcquireFromCondition) {
-  auto tp = CreateDefaultPool();
-
-  AcquireFromConditionStruct x;
-  x.value = 0;
-  x.done = false;
-  tp->Schedule(
-      std::bind(&WaitForCond2, &x));  // run WaitForCond2() in a thread T
-  // T will hang because the first invocation of ConditionWithAcquire() will
-  // return false.
-  absl::SleepFor(absl::Milliseconds(500));  // allow T time to hang
-
-  x.mu0.Lock();
-  x.cv.WaitWithTimeout(&x.mu0, absl::Milliseconds(500));  // wake T
-  // T will be woken because the Wait() will call ConditionWithAcquire()
-  // for the second time, and it will return true.
-
-  x.mu0.Unlock();
-
-  // T will then acquire the lock and recheck its own condition.
-  // It will find the condition true, as this is the third invocation,
-  // but the use of another Mutex by the calling function will
-  // cause the old mutex implementation to think that the outer
-  // LockWhen() has timed out because the inner LockWhenWithTimeout() did.
-  // T will then check the condition a fourth time because it finds a
-  // timeout occurred.  This should not happen in the new
-  // implementation that allows the Condition function to use Mutexes.
-
-  // It should also succeed, even though the Condition function
-  // is being invoked from CondVar::Wait, and thus this thread
-  // is conceptually waiting both on the condition variable, and on mu2.
-
-  x.mu0.LockWhen(absl::Condition(&x.done));
-  x.mu0.Unlock();
-}
-
-TEST(Mutex, DeadlockDetector) {
-  absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kAbort);
-
-  // check that we can call ForgetDeadlockInfo() on a lock with the lock held
-  absl::Mutex m1;
-  absl::Mutex m2;
-  absl::Mutex m3;
-  absl::Mutex m4;
-
-  m1.Lock();  // m1 gets ID1
-  m2.Lock();  // m2 gets ID2
-  m3.Lock();  // m3 gets ID3
-  m3.Unlock();
-  m2.Unlock();
-  // m1 still held
-  m1.ForgetDeadlockInfo();  // m1 loses ID
-  m2.Lock();                // m2 gets ID2
-  m3.Lock();                // m3 gets ID3
-  m4.Lock();                // m4 gets ID4
-  m3.Unlock();
-  m2.Unlock();
-  m4.Unlock();
-  m1.Unlock();
-}
-
-// Bazel has a test "warning" file that programs can write to if the
-// test should pass with a warning.  This class disables the warning
-// file until it goes out of scope.
-class ScopedDisableBazelTestWarnings {
- public:
-  ScopedDisableBazelTestWarnings() {
-#ifdef _WIN32
-    char file[MAX_PATH];
-    if (GetEnvironmentVariableA(kVarName, file, sizeof(file)) < sizeof(file)) {
-      warnings_output_file_ = file;
-      SetEnvironmentVariableA(kVarName, nullptr);
-    }
-#else
-    const char *file = getenv(kVarName);
-    if (file != nullptr) {
-      warnings_output_file_ = file;
-      unsetenv(kVarName);
-    }
-#endif
-  }
-
-  ~ScopedDisableBazelTestWarnings() {
-    if (!warnings_output_file_.empty()) {
-#ifdef _WIN32
-      SetEnvironmentVariableA(kVarName, warnings_output_file_.c_str());
-#else
-      setenv(kVarName, warnings_output_file_.c_str(), 0);
-#endif
-    }
-  }
-
- private:
-  static const char kVarName[];
-  std::string warnings_output_file_;
-};
-const char ScopedDisableBazelTestWarnings::kVarName[] =
-    "TEST_WARNINGS_OUTPUT_FILE";
-
-#ifdef ABSL_HAVE_THREAD_SANITIZER
-// This test intentionally creates deadlocks to test the deadlock detector.
-TEST(Mutex, DISABLED_DeadlockDetectorBazelWarning) {
-#else
-TEST(Mutex, DeadlockDetectorBazelWarning) {
-#endif
-  absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kReport);
-
-  // Cause deadlock detection to detect something, if it's
-  // compiled in and enabled.  But turn off the bazel warning.
-  ScopedDisableBazelTestWarnings disable_bazel_test_warnings;
-
-  absl::Mutex mu0;
-  absl::Mutex mu1;
-  bool got_mu0 = mu0.TryLock();
-  mu1.Lock();  // acquire mu1 while holding mu0
-  if (got_mu0) {
-    mu0.Unlock();
-  }
-  if (mu0.TryLock()) {  // try lock shouldn't cause deadlock detector to fire
-    mu0.Unlock();
-  }
-  mu0.Lock();  // acquire mu0 while holding mu1; should get one deadlock
-               // report here
-  mu0.Unlock();
-  mu1.Unlock();
-
-  absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kAbort);
-}
-
-// This test is tagged with NO_THREAD_SAFETY_ANALYSIS because the
-// annotation-based static thread-safety analysis is not currently
-// predicate-aware and cannot tell if the two for-loops that acquire and
-// release the locks have the same predicates.
-TEST(Mutex, DeadlockDetectorStressTest) ABSL_NO_THREAD_SAFETY_ANALYSIS {
-  // Stress test: Here we create a large number of locks and use all of them.
-  // If a deadlock detector keeps a full graph of lock acquisition order,
-  // it will likely be too slow for this test to pass.
-  const int n_locks = 1 << 17;
-  auto array_of_locks = absl::make_unique<absl::Mutex[]>(n_locks);
-  for (int i = 0; i < n_locks; i++) {
-    int end = std::min(n_locks, i + 5);
-    // acquire and then release locks i, i+1, ..., i+4
-    for (int j = i; j < end; j++) {
-      array_of_locks[j].Lock();
-    }
-    for (int j = i; j < end; j++) {
-      array_of_locks[j].Unlock();
-    }
-  }
-}
-
-#ifdef ABSL_HAVE_THREAD_SANITIZER
-// TSAN reports errors when locked Mutexes are destroyed.
-TEST(Mutex, DISABLED_DeadlockIdBug) NO_THREAD_SAFETY_ANALYSIS {
-#else
-TEST(Mutex, DeadlockIdBug) ABSL_NO_THREAD_SAFETY_ANALYSIS {
-#endif
-  // Test a scenario where a cached deadlock graph node id in the
-  // list of held locks is not invalidated when the corresponding
-  // mutex is deleted.
-  absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kAbort);
-  // Mutex that will be destroyed while being held
-  absl::Mutex *a = new absl::Mutex;
-  // Other mutexes needed by test
-  absl::Mutex b, c;
-
-  // Hold mutex.
-  a->Lock();
-
-  // Force deadlock id assignment by acquiring another lock.
-  b.Lock();
-  b.Unlock();
-
-  // Delete the mutex. The Mutex destructor tries to remove held locks,
-  // but the attempt isn't foolproof.  It can fail if:
-  //   (a) Deadlock detection is currently disabled.
-  //   (b) The destruction is from another thread.
-  // We exploit (a) by temporarily disabling deadlock detection.
-  absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kIgnore);
-  delete a;
-  absl::SetMutexDeadlockDetectionMode(absl::OnDeadlockCycle::kAbort);
-
-  // Now acquire another lock which will force a deadlock id assignment.
-  // We should end up getting assigned the same deadlock id that was
-  // freed up when "a" was deleted, which will cause a spurious deadlock
-  // report if the held lock entry for "a" was not invalidated.
-  c.Lock();
-  c.Unlock();
-}
-
-// --------------------------------------------------------
-// Test for timeouts/deadlines on condition waits that are specified using
-// absl::Duration and absl::Time.  For each waiting function we test with
-// a timeout/deadline that has already expired/passed, one that is infinite
-// and so never expires/passes, and one that will expire/pass in the near
-// future.
-
-static absl::Duration TimeoutTestAllowedSchedulingDelay() {
-  // Note: we use a function here because Microsoft Visual Studio fails to
-  // properly initialize constexpr static absl::Duration variables.
-  return absl::Milliseconds(150);
-}
-
-// Returns true if `actual_delay` is close enough to `expected_delay` to pass
-// the timeouts/deadlines test.  Otherwise, logs warnings and returns false.
-ABSL_MUST_USE_RESULT
-static bool DelayIsWithinBounds(absl::Duration expected_delay,
-                                absl::Duration actual_delay) {
-  bool pass = true;
-  // Do not allow the observed delay to be less than expected.  This may occur
-  // in practice due to clock skew or when the synchronization primitives use a
-  // different clock than absl::Now(), but these cases should be handled by the
-  // the retry mechanism in each TimeoutTest.
-  if (actual_delay < expected_delay) {
-    ABSL_RAW_LOG(WARNING,
-                 "Actual delay %s was too short, expected %s (difference %s)",
-                 absl::FormatDuration(actual_delay).c_str(),
-                 absl::FormatDuration(expected_delay).c_str(),
-                 absl::FormatDuration(actual_delay - expected_delay).c_str());
-    pass = false;
-  }
-  // If the expected delay is <= zero then allow a small error tolerance, since
-  // we do not expect context switches to occur during test execution.
-  // Otherwise, thread scheduling delays may be substantial in rare cases, so
-  // tolerate up to kTimeoutTestAllowedSchedulingDelay of error.
-  absl::Duration tolerance = expected_delay <= absl::ZeroDuration()
-                                 ? absl::Milliseconds(10)
-                                 : TimeoutTestAllowedSchedulingDelay();
-  if (actual_delay > expected_delay + tolerance) {
-    ABSL_RAW_LOG(WARNING,
-                 "Actual delay %s was too long, expected %s (difference %s)",
-                 absl::FormatDuration(actual_delay).c_str(),
-                 absl::FormatDuration(expected_delay).c_str(),
-                 absl::FormatDuration(actual_delay - expected_delay).c_str());
-    pass = false;
-  }
-  return pass;
-}
-
-// Parameters for TimeoutTest, below.
-struct TimeoutTestParam {
-  // The file and line number (used for logging purposes only).
-  const char *from_file;
-  int from_line;
-
-  // Should the absolute deadline API based on absl::Time be tested?  If false,
-  // the relative deadline API based on absl::Duration is tested.
-  bool use_absolute_deadline;
-
-  // The deadline/timeout used when calling the API being tested
-  // (e.g. Mutex::LockWhenWithDeadline).
-  absl::Duration wait_timeout;
-
-  // The delay before the condition will be set true by the test code.  If zero
-  // or negative, the condition is set true immediately (before calling the API
-  // being tested).  Otherwise, if infinite, the condition is never set true.
-  // Otherwise a closure is scheduled for the future that sets the condition
-  // true.
-  absl::Duration satisfy_condition_delay;
-
-  // The expected result of the condition after the call to the API being
-  // tested. Generally `true` means the condition was true when the API returns,
-  // `false` indicates an expected timeout.
-  bool expected_result;
-
-  // The expected delay before the API under test returns.  This is inherently
-  // flaky, so some slop is allowed (see `DelayIsWithinBounds` above), and the
-  // test keeps trying indefinitely until this constraint passes.
-  absl::Duration expected_delay;
-};
-
-// Print a `TimeoutTestParam` to a debug log.
-std::ostream &operator<<(std::ostream &os, const TimeoutTestParam &param) {
-  return os << "from: " << param.from_file << ":" << param.from_line
-            << " use_absolute_deadline: "
-            << (param.use_absolute_deadline ? "true" : "false")
-            << " wait_timeout: " << param.wait_timeout
-            << " satisfy_condition_delay: " << param.satisfy_condition_delay
-            << " expected_result: "
-            << (param.expected_result ? "true" : "false")
-            << " expected_delay: " << param.expected_delay;
-}
-
-std::string FormatString(const TimeoutTestParam &param) {
-  std::ostringstream os;
-  os << param;
-  return os.str();
-}
-
-// Like `thread::Executor::ScheduleAt` except:
-// a) Delays zero or negative are executed immediately in the current thread.
-// b) Infinite delays are never scheduled.
-// c) Calls this test's `ScheduleAt` helper instead of using `pool` directly.
-static void RunAfterDelay(absl::Duration delay,
-                          absl::synchronization_internal::ThreadPool *pool,
-                          const std::function<void()> &callback) {
-  if (delay <= absl::ZeroDuration()) {
-    callback();  // immediate
-  } else if (delay != absl::InfiniteDuration()) {
-    ScheduleAfter(pool, delay, callback);
-  }
-}
-
-class TimeoutTest : public ::testing::Test,
-                    public ::testing::WithParamInterface<TimeoutTestParam> {};
-
-std::vector<TimeoutTestParam> MakeTimeoutTestParamValues() {
-  // The `finite` delay is a finite, relatively short, delay.  We make it larger
-  // than our allowed scheduling delay (slop factor) to avoid confusion when
-  // diagnosing test failures.  The other constants here have clear meanings.
-  const absl::Duration finite = 3 * TimeoutTestAllowedSchedulingDelay();
-  const absl::Duration never = absl::InfiniteDuration();
-  const absl::Duration negative = -absl::InfiniteDuration();
-  const absl::Duration immediate = absl::ZeroDuration();
-
-  // Every test case is run twice; once using the absolute deadline API and once
-  // using the relative timeout API.
-  std::vector<TimeoutTestParam> values;
-  for (bool use_absolute_deadline : {false, true}) {
-    // Tests with a negative timeout (deadline in the past), which should
-    // immediately return current state of the condition.
-
-    // The condition is already true:
-    values.push_back(TimeoutTestParam{
-        __FILE__, __LINE__, use_absolute_deadline,
-        negative,   // wait_timeout
-        immediate,  // satisfy_condition_delay
-        true,       // expected_result
-        immediate,  // expected_delay
-    });
-
-    // The condition becomes true, but the timeout has already expired:
-    values.push_back(TimeoutTestParam{
-        __FILE__, __LINE__, use_absolute_deadline,
-        negative,  // wait_timeout
-        finite,    // satisfy_condition_delay
-        false,     // expected_result
-        immediate  // expected_delay
-    });
-
-    // The condition never becomes true:
-    values.push_back(TimeoutTestParam{
-        __FILE__, __LINE__, use_absolute_deadline,
-        negative,  // wait_timeout
-        never,     // satisfy_condition_delay
-        false,     // expected_result
-        immediate  // expected_delay
-    });
-
-    // Tests with an infinite timeout (deadline in the infinite future), which
-    // should only return when the condition becomes true.
-
-    // The condition is already true:
-    values.push_back(TimeoutTestParam{
-        __FILE__, __LINE__, use_absolute_deadline,
-        never,      // wait_timeout
-        immediate,  // satisfy_condition_delay
-        true,       // expected_result
-        immediate   // expected_delay
-    });
-
-    // The condition becomes true before the (infinite) expiry:
-    values.push_back(TimeoutTestParam{
-        __FILE__, __LINE__, use_absolute_deadline,
-        never,   // wait_timeout
-        finite,  // satisfy_condition_delay
-        true,    // expected_result
-        finite,  // expected_delay
-    });
-
-    // Tests with a (small) finite timeout (deadline soon), with the condition
-    // becoming true both before and after its expiry.
-
-    // The condition is already true:
-    values.push_back(TimeoutTestParam{
-        __FILE__, __LINE__, use_absolute_deadline,
-        never,      // wait_timeout
-        immediate,  // satisfy_condition_delay
-        true,       // expected_result
-        immediate   // expected_delay
-    });
-
-    // The condition becomes true before the expiry:
-    values.push_back(TimeoutTestParam{
-        __FILE__, __LINE__, use_absolute_deadline,
-        finite * 2,  // wait_timeout
-        finite,      // satisfy_condition_delay
-        true,        // expected_result
-        finite       // expected_delay
-    });
-
-    // The condition becomes true, but the timeout has already expired:
-    values.push_back(TimeoutTestParam{
-        __FILE__, __LINE__, use_absolute_deadline,
-        finite,      // wait_timeout
-        finite * 2,  // satisfy_condition_delay
-        false,       // expected_result
-        finite       // expected_delay
-    });
-
-    // The condition never becomes true:
-    values.push_back(TimeoutTestParam{
-        __FILE__, __LINE__, use_absolute_deadline,
-        finite,  // wait_timeout
-        never,   // satisfy_condition_delay
-        false,   // expected_result
-        finite   // expected_delay
-    });
-  }
-  return values;
-}
-
-// Instantiate `TimeoutTest` with `MakeTimeoutTestParamValues()`.
-INSTANTIATE_TEST_SUITE_P(All, TimeoutTest,
-                         testing::ValuesIn(MakeTimeoutTestParamValues()));
-
-TEST_P(TimeoutTest, Await) {
-  const TimeoutTestParam params = GetParam();
-  ABSL_RAW_LOG(INFO, "Params: %s", FormatString(params).c_str());
-
-  // Because this test asserts bounds on scheduling delays it is flaky.  To
-  // compensate it loops forever until it passes.  Failures express as test
-  // timeouts, in which case the test log can be used to diagnose the issue.
-  for (int attempt = 1;; ++attempt) {
-    ABSL_RAW_LOG(INFO, "Attempt %d", attempt);
-
-    absl::Mutex mu;
-    bool value = false;  // condition value (under mu)
-
-    std::unique_ptr<absl::synchronization_internal::ThreadPool> pool =
-        CreateDefaultPool();
-    RunAfterDelay(params.satisfy_condition_delay, pool.get(), [&] {
-      absl::MutexLock l(&mu);
-      value = true;
-    });
-
-    absl::MutexLock lock(&mu);
-    absl::Time start_time = absl::Now();
-    absl::Condition cond(&value);
-    bool result =
-        params.use_absolute_deadline
-            ? mu.AwaitWithDeadline(cond, start_time + params.wait_timeout)
-            : mu.AwaitWithTimeout(cond, params.wait_timeout);
-    if (DelayIsWithinBounds(params.expected_delay, absl::Now() - start_time)) {
-      EXPECT_EQ(params.expected_result, result);
-      break;
-    }
-  }
-}
-
-TEST_P(TimeoutTest, LockWhen) {
-  const TimeoutTestParam params = GetParam();
-  ABSL_RAW_LOG(INFO, "Params: %s", FormatString(params).c_str());
-
-  // Because this test asserts bounds on scheduling delays it is flaky.  To
-  // compensate it loops forever until it passes.  Failures express as test
-  // timeouts, in which case the test log can be used to diagnose the issue.
-  for (int attempt = 1;; ++attempt) {
-    ABSL_RAW_LOG(INFO, "Attempt %d", attempt);
-
-    absl::Mutex mu;
-    bool value = false;  // condition value (under mu)
-
-    std::unique_ptr<absl::synchronization_internal::ThreadPool> pool =
-        CreateDefaultPool();
-    RunAfterDelay(params.satisfy_condition_delay, pool.get(), [&] {
-      absl::MutexLock l(&mu);
-      value = true;
-    });
-
-    absl::Time start_time = absl::Now();
-    absl::Condition cond(&value);
-    bool result =
-        params.use_absolute_deadline
-            ? mu.LockWhenWithDeadline(cond, start_time + params.wait_timeout)
-            : mu.LockWhenWithTimeout(cond, params.wait_timeout);
-    mu.Unlock();
-
-    if (DelayIsWithinBounds(params.expected_delay, absl::Now() - start_time)) {
-      EXPECT_EQ(params.expected_result, result);
-      break;
-    }
-  }
-}
-
-TEST_P(TimeoutTest, ReaderLockWhen) {
-  const TimeoutTestParam params = GetParam();
-  ABSL_RAW_LOG(INFO, "Params: %s", FormatString(params).c_str());
-
-  // Because this test asserts bounds on scheduling delays it is flaky.  To
-  // compensate it loops forever until it passes.  Failures express as test
-  // timeouts, in which case the test log can be used to diagnose the issue.
-  for (int attempt = 0;; ++attempt) {
-    ABSL_RAW_LOG(INFO, "Attempt %d", attempt);
-
-    absl::Mutex mu;
-    bool value = false;  // condition value (under mu)
-
-    std::unique_ptr<absl::synchronization_internal::ThreadPool> pool =
-        CreateDefaultPool();
-    RunAfterDelay(params.satisfy_condition_delay, pool.get(), [&] {
-      absl::MutexLock l(&mu);
-      value = true;
-    });
-
-    absl::Time start_time = absl::Now();
-    bool result =
-        params.use_absolute_deadline
-            ? mu.ReaderLockWhenWithDeadline(absl::Condition(&value),
-                                            start_time + params.wait_timeout)
-            : mu.ReaderLockWhenWithTimeout(absl::Condition(&value),
-                                           params.wait_timeout);
-    mu.ReaderUnlock();
-
-    if (DelayIsWithinBounds(params.expected_delay, absl::Now() - start_time)) {
-      EXPECT_EQ(params.expected_result, result);
-      break;
-    }
-  }
-}
-
-TEST_P(TimeoutTest, Wait) {
-  const TimeoutTestParam params = GetParam();
-  ABSL_RAW_LOG(INFO, "Params: %s", FormatString(params).c_str());
-
-  // Because this test asserts bounds on scheduling delays it is flaky.  To
-  // compensate it loops forever until it passes.  Failures express as test
-  // timeouts, in which case the test log can be used to diagnose the issue.
-  for (int attempt = 0;; ++attempt) {
-    ABSL_RAW_LOG(INFO, "Attempt %d", attempt);
-
-    absl::Mutex mu;
-    bool value = false;  // condition value (under mu)
-    absl::CondVar cv;    // signals a change of `value`
-
-    std::unique_ptr<absl::synchronization_internal::ThreadPool> pool =
-        CreateDefaultPool();
-    RunAfterDelay(params.satisfy_condition_delay, pool.get(), [&] {
-      absl::MutexLock l(&mu);
-      value = true;
-      cv.Signal();
-    });
-
-    absl::MutexLock lock(&mu);
-    absl::Time start_time = absl::Now();
-    absl::Duration timeout = params.wait_timeout;
-    absl::Time deadline = start_time + timeout;
-    while (!value) {
-      if (params.use_absolute_deadline ? cv.WaitWithDeadline(&mu, deadline)
-                                       : cv.WaitWithTimeout(&mu, timeout)) {
-        break;  // deadline/timeout exceeded
-      }
-      timeout = deadline - absl::Now();  // recompute
-    }
-    bool result = value;  // note: `mu` is still held
-
-    if (DelayIsWithinBounds(params.expected_delay, absl::Now() - start_time)) {
-      EXPECT_EQ(params.expected_result, result);
-      break;
-    }
-  }
-}
-
-TEST(Mutex, Logging) {
-  // Allow user to look at logging output
-  absl::Mutex logged_mutex;
-  logged_mutex.EnableDebugLog("fido_mutex");
-  absl::CondVar logged_cv;
-  logged_cv.EnableDebugLog("rover_cv");
-  logged_mutex.Lock();
-  logged_cv.WaitWithTimeout(&logged_mutex, absl::Milliseconds(20));
-  logged_mutex.Unlock();
-  logged_mutex.ReaderLock();
-  logged_mutex.ReaderUnlock();
-  logged_mutex.Lock();
-  logged_mutex.Unlock();
-  logged_cv.Signal();
-  logged_cv.SignalAll();
-}
-
-// --------------------------------------------------------
-
-// Generate the vector of thread counts for tests parameterized on thread count.
-static std::vector<int> AllThreadCountValues() {
-  if (kExtendedTest) {
-    return {2, 4, 8, 10, 16, 20, 24, 30, 32};
-  }
-  return {2, 4, 10};
-}
-
-// A test fixture parameterized by thread count.
-class MutexVariableThreadCountTest : public ::testing::TestWithParam<int> {};
-
-// Instantiate the above with AllThreadCountOptions().
-INSTANTIATE_TEST_SUITE_P(ThreadCounts, MutexVariableThreadCountTest,
-                         ::testing::ValuesIn(AllThreadCountValues()),
-                         ::testing::PrintToStringParamName());
-
-// Reduces iterations by some factor for slow platforms
-// (determined empirically).
-static int ScaleIterations(int x) {
-  // ABSL_MUTEX_READER_LOCK_IS_EXCLUSIVE is set in the implementation
-  // of Mutex that uses either std::mutex or pthread_mutex_t. Use
-  // these as keys to determine the slow implementation.
-#if defined(ABSL_MUTEX_READER_LOCK_IS_EXCLUSIVE)
-  return x / 10;
-#else
-  return x;
-#endif
-}
-
-TEST_P(MutexVariableThreadCountTest, Mutex) {
-  int threads = GetParam();
-  int iterations = ScaleIterations(10000000) / threads;
-  int operations = threads * iterations;
-  EXPECT_EQ(RunTest(&TestMu, threads, iterations, operations), operations);
-#if !defined(ABSL_MUTEX_ENABLE_INVARIANT_DEBUGGING_NOT_IMPLEMENTED)
-  iterations = std::min(iterations, 10);
-  operations = threads * iterations;
-  EXPECT_EQ(RunTestWithInvariantDebugging(&TestMu, threads, iterations,
-                                          operations, CheckSumG0G1),
-            operations);
-#endif
-}
-
-TEST_P(MutexVariableThreadCountTest, Try) {
-  int threads = GetParam();
-  int iterations = 1000000 / threads;
-  int operations = iterations * threads;
-  EXPECT_EQ(RunTest(&TestTry, threads, iterations, operations), operations);
-#if !defined(ABSL_MUTEX_ENABLE_INVARIANT_DEBUGGING_NOT_IMPLEMENTED)
-  iterations = std::min(iterations, 10);
-  operations = threads * iterations;
-  EXPECT_EQ(RunTestWithInvariantDebugging(&TestTry, threads, iterations,
-                                          operations, CheckSumG0G1),
-            operations);
-#endif
-}
-
-TEST_P(MutexVariableThreadCountTest, R20ms) {
-  int threads = GetParam();
-  int iterations = 100;
-  int operations = iterations * threads;
-  EXPECT_EQ(RunTest(&TestR20ms, threads, iterations, operations), 0);
-}
-
-TEST_P(MutexVariableThreadCountTest, RW) {
-  int threads = GetParam();
-  int iterations = ScaleIterations(20000000) / threads;
-  int operations = iterations * threads;
-  EXPECT_EQ(RunTest(&TestRW, threads, iterations, operations), operations / 2);
-#if !defined(ABSL_MUTEX_ENABLE_INVARIANT_DEBUGGING_NOT_IMPLEMENTED)
-  iterations = std::min(iterations, 10);
-  operations = threads * iterations;
-  EXPECT_EQ(RunTestWithInvariantDebugging(&TestRW, threads, iterations,
-                                          operations, CheckSumG0G1),
-            operations / 2);
-#endif
-}
-
-TEST_P(MutexVariableThreadCountTest, Await) {
-  int threads = GetParam();
-  int iterations = ScaleIterations(500000);
-  int operations = iterations;
-  EXPECT_EQ(RunTest(&TestAwait, threads, iterations, operations), operations);
-}
-
-TEST_P(MutexVariableThreadCountTest, SignalAll) {
-  int threads = GetParam();
-  int iterations = 200000 / threads;
-  int operations = iterations;
-  EXPECT_EQ(RunTest(&TestSignalAll, threads, iterations, operations),
-            operations);
-}
-
-TEST(Mutex, Signal) {
-  int threads = 2;  // TestSignal must use two threads
-  int iterations = 200000;
-  int operations = iterations;
-  EXPECT_EQ(RunTest(&TestSignal, threads, iterations, operations), operations);
-}
-
-TEST(Mutex, Timed) {
-  int threads = 10;  // Use a fixed thread count of 10
-  int iterations = 1000;
-  int operations = iterations;
-  EXPECT_EQ(RunTest(&TestCVTimeout, threads, iterations, operations),
-            operations);
-}
-
-TEST(Mutex, CVTime) {
-  int threads = 10;  // Use a fixed thread count of 10
-  int iterations = 1;
-  EXPECT_EQ(RunTest(&TestCVTime, threads, iterations, 1),
-            threads * iterations);
-}
-
-TEST(Mutex, MuTime) {
-  int threads = 10;  // Use a fixed thread count of 10
-  int iterations = 1;
-  EXPECT_EQ(RunTest(&TestMuTime, threads, iterations, 1), threads * iterations);
-}
-
-}  // namespace