text: /*
   * Copyright (c) Meta Platforms, Inc. and affiliates.
   *
   * 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 <folly/futures/ManualTimekeeper.h>
  
  #include <chrono>
  
  #include <folly/portability/GTest.h>
  
  using namespace std::literals;
  
  namespace folly {
  
  class ManualTimekeeperTest : public ::testing::Test {};
  
  TEST_F(ManualTimekeeperTest, Basic) {
    auto timekeeper = folly::ManualTimekeeper{};
    auto future = timekeeper.after(100s);
    timekeeper.advance(100s);
    EXPECT_TRUE(future.isReady());
  }
  
  TEST_F(ManualTimekeeperTest, AdvanceWithoutAnyFutures) {
    auto timekeeper = folly::ManualTimekeeper{};
    timekeeper.advance(100s);
    auto future = timekeeper.after(100s);
    EXPECT_FALSE(future.isReady());
    timekeeper.advance(100s);
    EXPECT_TRUE(future.isReady());
  }
  
  TEST_F(ManualTimekeeperTest, AdvanceWithManyFutures) {
    auto timekeeper = folly::ManualTimekeeper{};
  
    auto one = timekeeper.after(100s);
    auto two = timekeeper.after(200s);
    auto three = timekeeper.after(300s);
  
    EXPECT_FALSE(one.isReady());
    EXPECT_FALSE(two.isReady());
    EXPECT_FALSE(three.isReady());
  
    timekeeper.advance(100s);
  
    EXPECT_TRUE(one.isReady());
    EXPECT_FALSE(two.isReady());
    EXPECT_FALSE(three.isReady());
  
    timekeeper.advance(100s);
  
    EXPECT_TRUE(one.isReady());
    EXPECT_TRUE(two.isReady());
    EXPECT_FALSE(three.isReady());
  
    timekeeper.advance(100s);
  
    EXPECT_TRUE(one.isReady());
    EXPECT_TRUE(two.isReady());
    EXPECT_TRUE(three.isReady());
  
    timekeeper.advance(100s);
  
    EXPECT_TRUE(one.isReady());
    EXPECT_TRUE(two.isReady());
    EXPECT_TRUE(three.isReady());
  
    auto four = timekeeper.after(100s);
  
    EXPECT_FALSE(four.isReady());
  
    timekeeper.advance(100s);
  
    EXPECT_TRUE(one.isReady());
    EXPECT_TRUE(two.isReady());
    EXPECT_TRUE(three.isReady());
    EXPECT_TRUE(four.isReady());
  }
  
  } // namespace folly
  