text: // Copyright 2021 gRPC 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 "src/core/lib/promise/try_join.h"
  
  #include <functional>
  #include <tuple>
  #include <utility>
  
  #include "absl/utility/utility.h"
  #include "gtest/gtest.h"
  
  namespace grpc_core {
  
  template <typename T>
  using P = std::function<Poll<absl::StatusOr<T>>()>;
  
  template <typename T>
  P<T> instant_ok(T x) {
    return [x] { return absl::StatusOr<T>(x); };
  }
  
  template <typename T>
  P<T> instant_fail() {
    return [] { return absl::StatusOr<T>(); };
  }
  
  template <typename... T>
  Poll<absl::StatusOr<std::tuple<T...>>> ok(T... x) {
    return absl::StatusOr<std::tuple<T...>>(absl::in_place, x...);
  }
  
  template <typename... T>
  Poll<absl::StatusOr<std::tuple<T...>>> fail() {
    return absl::StatusOr<std::tuple<T...>>();
  }
  
  template <typename T>
  P<T> pending() {
    return []() -> Poll<absl::StatusOr<T>> { return Pending(); };
  }
  
  TEST(TryJoinTest, Join1) { EXPECT_EQ(TryJoin(instant_ok(1))(), ok(1)); }
  
  TEST(TryJoinTest, Join1Fail) {
    EXPECT_EQ(TryJoin(instant_fail<int>())(), fail<int>());
  }
  
  TEST(TryJoinTest, Join2Success) {
    EXPECT_EQ(TryJoin(instant_ok(1), instant_ok(2))(), ok(1, 2));
  }
  
  TEST(TryJoinTest, Join2Fail1) {
    EXPECT_EQ(TryJoin(instant_ok(1), instant_fail<int>())(), (fail<int, int>()));
  }
  
  TEST(TryJoinTest, Join2Fail2) {
    EXPECT_EQ(TryJoin(instant_fail<int>(), instant_ok(2))(), (fail<int, int>()));
  }
  
  TEST(TryJoinTest, Join2Fail1P) {
    EXPECT_EQ(TryJoin(pending<int>(), instant_fail<int>())(), (fail<int, int>()));
  }
  
  TEST(TryJoinTest, Join2Fail2P) {
    EXPECT_EQ(TryJoin(instant_fail<int>(), pending<int>())(), (fail<int, int>()));
  }
  
  }  // namespace grpc_core
  
  int main(int argc, char** argv) {
    ::testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
  }
  