1 // 301-Gen-MapTypeConversion.cpp 2 // Shows how to use map to modify generator's return type. 3 4 // TODO 5 6 #include <catch2/catch.hpp> 7 8 #include <string> 9 #include <sstream> 10 11 // Returns a line from a stream. You could have it e.g. read lines from 12 // a file, but to avoid problems with paths in examples, we will use 13 // a fixed stringstream. 14 class LineGenerator : public Catch::Generators::IGenerator<std::string> { 15 std::string m_line; 16 std::stringstream m_stream; 17 public: LineGenerator()18 LineGenerator() { 19 m_stream.str("1\n2\n3\n4\n"); 20 if (!next()) { 21 throw Catch::GeneratorException("Couldn't read a single line"); 22 } 23 } 24 get() const25 std::string const& get() const override { 26 return m_line; 27 } 28 next()29 bool next() override { 30 return !!std::getline(m_stream, m_line); 31 } 32 }; 33 34 // This helper function provides a nicer UX when instantiating the generator 35 // Notice that it returns an instance of GeneratorWrapper<std::string>, which 36 // is a value-wrapper around std::unique_ptr<IGenerator<std::string>>. lines(std::string)37Catch::Generators::GeneratorWrapper<std::string> lines(std::string /* ignored for example */) { 38 return Catch::Generators::GeneratorWrapper<std::string>( 39 std::unique_ptr<Catch::Generators::IGenerator<std::string>>( 40 new LineGenerator() 41 ) 42 ); 43 } 44 45 46 47 TEST_CASE("filter can convert types inside the generator expression", "[example][generator]") { __anonf1d2ebcb0102(std::string const& line) 48 auto num = GENERATE(map<int>([](std::string const& line) { return std::stoi(line); }, 49 lines("fake-file"))); 50 51 REQUIRE(num > 0); 52 } 53 54 // Compiling and running this file will result in 4 successful assertions 55