Core/Utilities/FunctionCompositionTests.cpp

0001 // This file is part of the ACTS project.
0002 //
0003 // Copyright (C) 2016 CERN for the benefit of the ACTS project
0004 //
0005 // This Source Code Form is subject to the terms of the Mozilla Public
0006 // License, v. 2.0. If a copy of the MPL was not distributed with this
0007 // file, You can obtain one at https://mozilla.org/MPL/2.0/.
0008
0009 #include <boost/test/unit_test.hpp>
0010
0011 #include "Acts/Utilities/FunctionComposition.hpp"
0012
0013 #include <memory>
0014 #include <string>
0015
0016 namespace ActsTests {
0017
0018 BOOST_AUTO_TEST_SUITE(UtilitiesSuite)
0019
0020 BOOST_AUTO_TEST_CASE(ComposeTwoFunctions) {
0021   auto addOne = [](int x) { return x + 1; };
0022   auto doubleValue = [](int x) { return 2 * x; };
0023
0024   auto composed = Acts::compose(doubleValue, addOne);
0025
0026   BOOST_CHECK_EQUAL(composed(3), 8);
0027 }
0028
0029 BOOST_AUTO_TEST_CASE(ComposeMultipleFunctions) {
0030   auto decorate = [](const std::string& s) { return "[" + s + "]"; };
0031   auto appendB = [](const std::string& s) { return s + "b"; };
0032   auto appendA = [](const std::string& s) { return s + "a"; };
0033
0034   auto composed = Acts::compose(decorate, appendB, appendA);
0035
0036   BOOST_CHECK_EQUAL(composed(std::string{"x"}), "[xab]");
0037 }
0038
0039 BOOST_AUTO_TEST_CASE(ComposeForwardsMoveOnlyInput) {
0040   auto timesTwo = [](int x) { return x * 2; };
0041   auto takeOwnership = [](std::unique_ptr<int> ptr) { return *ptr + 1; };
0042
0043   auto composed = Acts::compose(timesTwo, takeOwnership);
0044
0045   BOOST_CHECK_EQUAL(composed(std::make_unique<int>(4)), 10);
0046 }
0047
0048 BOOST_AUTO_TEST_SUITE_END()
0049
0050 }  // namespace ActsTests