[Boost-users] [test] User objects with BOOST_CHECK_EQUAL

From: Robert Dailey (rcdailey_at_[hidden])
Date: 2008-05-02 15:54:19

Hi,

I'm having a bit of trouble getting user-defined objects working with
Boost.Test. I skimmed through the docs and I didn't see anything on this
subject, but the boost documentation isn't the most intuitive documentation,
so it is a bit easy to miss obvious stuff like this.

Anyway, I have a class named "Foo", and I've given it an overloaded boolean
== operator. When I do the following, it fails to compile under MSVC9:

Foo a, b;
BOOST_TEST_EQUAL( a, b );

The class is defined as follows:

class Foo
{
private:
    std::string data;

public:
    Foo()
        : data( "Testing 123" )
    {}

    Foo( Foo const& other )
    {
        data = other.data;
    }

    bool operator== ( Foo const& operand )
    {
        return data == operand.data;
    }
};

Below is the error I'm getting. How can I make this work? I've truncated it
a little bit since it's insanely long:

1>c:\it\tfs\crusades\sdks\boost\boost\test\test_tools.hpp(342) : error
C2679: binary '<<' : no operator found which takes a right-hand operand of
type 'const Foo' (or there is no acceptable conversion)
1>        c:\program files\microsoft visual studio
9.0\vc\include\ostream(653): could be 'std::basic_ostream<_Elem,_Traits>
&std::operator
<<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,const
char *)' [found using argument-dependent lookup]
1>        with
1>        [
1>            _Elem=char,
1>            _Traits=std::char_traits<char>
1>        ]
1>        c:\program files\microsoft visual studio
9.0\vc\include\ostream(700): or       'std::basic_ostream<_Elem,_Traits>
&std::operator
<<<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits> &,char)'
[found using argument-dependent lookup]
1>        with
1>        [
1>            _Elem=char,
1>            _Traits=std::char_traits<char>
1>        ]
1>        c:\program files\microsoft visual studio
9.0\vc\include\ostream(738): or       'std::basic_ostream<_Elem,_Traits>
&std::operator <<<std::char_traits<char>>(std::basic_ostream<_Elem,_Traits>
&,const char *)' [found using argument-dependent lookup]
1>        with
1>        [
1>            _Elem=char,
1>            _Traits=std::char_traits<char>
1>        ]