OS: Update Handler unittest

#include "os/handler.h"

#include <sys/eventfd.h>

#include <future>

#include <thread>

#include "gtest/gtest.h"

#include "os/log.h"

namespace bluetooth {

namespace os {

TEST_F(HandlerTest, post_task_invoked) {

  int val = 0;

  Closure closure = [&val]() { val++; };

  std::promise<void> closure_ran;

  Closure closure = [&val, &closure_ran]() {

    val++;

    closure_ran.set_value();

  };

  handler_->Post(closure);

  std::this_thread::sleep_for(std::chrono::milliseconds(10));

  EXPECT_EQ(val, 1);

  closure_ran.get_future().wait();

  ASSERT_EQ(val, 1);

}

TEST_F(HandlerTest, post_task_cleared) {

  int val = 0;

  Closure closure = [&val]() {

  std::promise<void> closure_started;

  std::promise<void> closure_can_continue;

  auto can_continue_future = closure_can_continue.get_future();

  handler_->Post([&val, &can_continue_future, &closure_started]() {

    closure_started.set_value();

    val++;

    std::this_thread::sleep_for(std::chrono::milliseconds(5));

  };

  handler_->Post(std::move(closure));

  closure = []() {

    ASSERT_TRUE(false);

  };

  std::this_thread::sleep_for(std::chrono::milliseconds(5));

  handler_->Post(std::move(closure));

    can_continue_future.wait();

  });

  handler_->Post([]() { ASSERT_TRUE(false); });

  closure_started.get_future().wait();

  handler_->Clear();

  std::this_thread::sleep_for(std::chrono::milliseconds(10));

  EXPECT_EQ(val, 1);

  closure_can_continue.set_value();

  ASSERT_EQ(val, 1);

}

}  // namespace