1 // Copyright 2021 The Chromium Authors 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_TEST_TEST_FUTURE_INTERNAL_H_ 6 #define BASE_TEST_TEST_FUTURE_INTERNAL_H_ 7 8 #include <tuple> 9 #include <type_traits> 10 11 namespace base::test::internal { 12 13 // Helper to only implement a method if the future holds one or more values. 14 template <typename Tuple> 15 concept IsNonEmptyTuple = std::tuple_size<Tuple>::value > 0; 16 17 // Helper to only implement a method if the future holds a single value. 18 template <typename Tuple> 19 concept IsSingleValuedTuple = std::tuple_size<Tuple>::value == 1; 20 21 // Helper to only implement a method if the future holds multiple values. 22 template <typename Tuple> 23 concept IsMultiValuedTuple = std::tuple_size<Tuple>::value > 1; 24 25 } // namespace base::test::internal 26 27 #endif // BASE_TEST_TEST_FUTURE_INTERNAL_H_ 28