| // 310-Gen-VariablesInGenerator.cpp |
| // Shows how to use variables when creating generators. |
| |
| // Note that using variables inside generators is dangerous and should |
| // be done only if you know what you are doing, because the generators |
| // _WILL_ outlive the variables -- thus they should be either captured |
| // by value directly, or copied by the generators during construction. |
| |
| #include <catch2/catch.hpp> |
| |
| TEST_CASE("Generate random doubles across different ranges", |
| "[generator][example][advanced]") { |
| // Workaround for old libstdc++ |
| using record = std::tuple<double, double>; |
| // Set up 3 ranges to generate numbers from |
| auto r = GENERATE(table<double, double>({ |
| record{3, 4}, |
| record{-4, -3}, |
| record{10, 1000} |
| })); |
| |
| // This will not compile (intentionally), because it accesses a variable |
| // auto number = GENERATE(take(50, random(std::get<0>(r), std::get<1>(r)))); |
| |
| // GENERATE_COPY copies all variables mentioned inside the expression |
| // thus this will work. |
| auto number = GENERATE_COPY(take(50, random(std::get<0>(r), std::get<1>(r)))); |
| |
| REQUIRE(std::abs(number) > 0); |
| } |
| |
| // Compiling and running this file will result in 150 successful assertions |
| |