catch2/projects/SelfTest/ToStringPair.cpp

#include "catch.hpp"

// === Pair ===
namespace Catch {
    // Note: If we put this in the right place in catch_tostring, then
    // we can make it an overload of Catch::toString
    template<typename T1, typename T2>
    struct StringMaker<std::pair<T1,T2> > {
        static std::string convert( const std::pair<T1,T2>& pair ) {
            std::ostringstream oss;
            oss << "{ "
                << toString( pair.first )
                << ", "
                << toString( pair.second )
                << " }";
            return oss.str();
        }
    };
}

TEST_CASE( "std::pair<int,std::string> -> toString", "[toString][pair]" ) {
    std::pair<int,std::string> value( 34, "xyzzy" );
    REQUIRE( Catch::toString( value ) == "{ 34, \"xyzzy\" }" );
}

TEST_CASE( "std::pair<int,const std::string> -> toString", "[toString][pair]" ) {
    std::pair<int,const std::string> value( 34, "xyzzy" );
    REQUIRE( Catch::toString(value) == "{ 34, \"xyzzy\" }" );
}

TEST_CASE( "std::vector<std::pair<std::string,int> > -> toString", "[toString][pair]" ) {
    std::vector<std::pair<std::string,int> > pr;
    pr.push_back( std::make_pair("green", 55 ) );
    REQUIRE( Catch::toString( pr ) == "{ { \"green\", 55 } }" );
}

// This is pretty contrived - I figure if this works, anything will...
TEST_CASE( "pair<pair<int,const char *,pair<std::string,int> > -> toString", "[toString][pair]" ) {
    typedef std::pair<int,const char *> left_t;
    typedef std::pair<std::string,int> right_t;

    left_t  left( 42, "Arthur" );
    right_t right( "Ford", 24 );

    std::pair<left_t,right_t> pair( left, right );
    REQUIRE( Catch::toString( pair ) == "{ { 42, \"Arthur\" }, { \"Ford\", 24 } }" );
}