Add missing include to "meetup" exercise test file

[collenjones]

This diff addresses the following issue where the tests assume the streaming operators will be included in meetup.h. We should not force this dependency on the user's code.

Clang++ 6.0.1
Boost version: 1.67.0_1

Error

[ 33%] Building CXX object CMakeFiles/meetup.dir/meetup_test.cpp.o
In file included from /Users/collen/exercism/cpp/meetup/meetup_test.cpp:3:
In file included from /usr/local/include/boost/test/unit_test.hpp:18:
In file included from /usr/local/include/boost/test/test_tools.hpp:46:
In file included from /usr/local/include/boost/test/tools/old/impl.hpp:24:
/usr/local/include/boost/test/tools/detail/print_helper.hpp:52:13: error: static_assert failed due to requirement 'boost::has_left_shift<std::ostream,
      date>::value' "Type has to implement operator<< to be printable"
            BOOST_STATIC_ASSERT_MSG( (boost::has_left_shift<std::ostream,T>::value),
            ^                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/local/include/boost/static_assert.hpp:31:45: note: expanded from macro 'BOOST_STATIC_ASSERT_MSG'
#     define BOOST_STATIC_ASSERT_MSG( ... ) static_assert(__VA_ARGS__)
                                            ^             ~~~~~~~~~~~
/usr/local/include/boost/test/tools/detail/print_helper.hpp:61:24: note: in instantiation of function template specialization
      'boost::test_tools::tt_detail::impl::boost_test_print_type<boost::gregorian::date>' requested here
                return boost_test_print_type(ostr, r);
                       ^
/usr/local/include/boost/test/tools/detail/print_helper.hpp:90:9: note: in instantiation of function template specialization
      'boost::test_tools::tt_detail::impl::boost_test_print_type_impl::operator()<boost::gregorian::date>' requested here
        boost_test_print_type(ostr, t);
        ^
/usr/local/include/boost/test/tools/detail/print_helper.hpp:219:5: note: in instantiation of member function
      'boost::test_tools::tt_detail::print_log_value<boost::gregorian::date>::operator()' requested here
    print_log_value<T>()( ostr, ph.m_t );
    ^
/usr/local/include/boost/test/utils/lazy_ostream.hpp:66:29: note: in instantiation of function template specialization
      'boost::test_tools::tt_detail::operator<<<boost::gregorian::date>' requested here
        return m_prev(ostr) << m_value;
                            ^
/usr/local/include/boost/test/tools/old/impl.hpp:92:50: note: in instantiation of member function
      'boost::unit_test::lazy_ostream_impl<boost::unit_test::lazy_ostream, boost::test_tools::tt_detail::print_helper_t<boost::gregorian::date>, const
      boost::test_tools::tt_detail::print_helper_t<boost::gregorian::date> &>::operator()' requested here
BOOST_PP_REPEAT( BOOST_TEST_MAX_PREDICATE_ARITY, IMPL_FRWD, _ )
                                                 ^
/usr/local/include/boost/preprocessor/repetition/repeat.hpp:29:26: note: expanded from macro 'BOOST_PP_REPEAT'
# define BOOST_PP_REPEAT BOOST_PP_CAT(BOOST_PP_REPEAT_, BOOST_PP_AUTO_REC(BOOST_PP_REPEAT_P, 4))
                         ^
/usr/local/include/boost/preprocessor/cat.hpp:22:32: note: expanded from macro 'BOOST_PP_CAT'
#    define BOOST_PP_CAT(a, b) BOOST_PP_CAT_I(a, b)
                               ^
/usr/local/include/boost/preprocessor/cat.hpp:29:34: note: expanded from macro 'BOOST_PP_CAT_I'
#    define BOOST_PP_CAT_I(a, b) a ## b
                                 ^
<scratch space>:67:1: note: expanded from here
BOOST_PP_REPEAT_1
^
/Users/collen/exercism/cpp/meetup/meetup_test.cpp:13:5: note: in instantiation of function template specialization
      'boost::test_tools::tt_detail::check_frwd<boost::test_tools::tt_detail::equal_impl_frwd, boost::gregorian::date, boost::gregorian::date>'
      requested here
    BOOST_REQUIRE_EQUAL(expected, meetup.monteenth());
    ^
/usr/local/include/boost/test/tools/old/interface.hpp:154:45: note: expanded from macro 'BOOST_REQUIRE_EQUAL'
#define BOOST_REQUIRE_EQUAL( L, R )         BOOST_TEST_TOOL_IMPL( 0, \
                                            ^
/usr/local/include/boost/test/tools/old/interface.hpp:65:47: note: expanded from macro 'BOOST_TEST_TOOL_IMPL'
    BOOST_PP_IF( frwd_type, report_assertion, check_frwd ) (                    \
                                              ^
In file included from /Users/collen/exercism/cpp/meetup/meetup_test.cpp:3:
In file included from /usr/local/include/boost/test/unit_test.hpp:18:
In file included from /usr/local/include/boost/test/test_tools.hpp:46:
In file included from /usr/local/include/boost/test/tools/old/impl.hpp:24:
/usr/local/include/boost/test/tools/detail/print_helper.hpp:54:18: error: invalid operands to binary expression ('std::ostream'
      (aka 'basic_ostream<char>') and 'const boost::gregorian::date')
            ostr << t;
            ~~~~ ^  ~
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:218:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'const void *' for 1st argument; take the address of the argument with &
    basic_ostream& operator<<(const void* __p);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:194:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'std::__1::basic_ostream<char> &(*)(std::__1::basic_ostream<char> &)' for 1st argument
    basic_ostream& operator<<(basic_ostream& (*__pf)(basic_ostream&))
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:198:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'basic_ios<std::__1::basic_ostream<char, std::__1::char_traits<char> >::char_type,
      std::__1::basic_ostream<char, std::__1::char_traits<char> >::traits_type> &(*)(basic_ios<std::__1::basic_ostream<char,
      std::__1::char_traits<char> >::char_type, std::__1::basic_ostream<char, std::__1::char_traits<char> >::traits_type> &)' (aka 'basic_ios<char,
      std::__1::char_traits<char> > &(*)(basic_ios<char, std::__1::char_traits<char> > &)') for 1st argument
    basic_ostream& operator<<(basic_ios<char_type, traits_type>&
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:203:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'std::__1::ios_base &(*)(std::__1::ios_base &)' for 1st argument
    basic_ostream& operator<<(ios_base& (*__pf)(ios_base&))
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:206:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'bool' for 1st argument
    basic_ostream& operator<<(bool __n);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:207:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'short' for 1st argument
    basic_ostream& operator<<(short __n);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:208:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'unsigned short' for 1st argument
    basic_ostream& operator<<(unsigned short __n);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:209:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'int' for 1st argument
    basic_ostream& operator<<(int __n);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:210:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'unsigned int' for 1st argument
    basic_ostream& operator<<(unsigned int __n);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:211:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'long' for 1st argument
    basic_ostream& operator<<(long __n);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:212:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'unsigned long' for 1st argument
    basic_ostream& operator<<(unsigned long __n);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:213:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'long long' for 1st argument
    basic_ostream& operator<<(long long __n);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:214:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'unsigned long long' for 1st argument
    basic_ostream& operator<<(unsigned long long __n);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:215:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'float' for 1st argument
    basic_ostream& operator<<(float __f);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:216:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'double' for 1st argument
    basic_ostream& operator<<(double __f);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:217:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'long double' for 1st argument
    basic_ostream& operator<<(long double __f);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:219:20: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'basic_streambuf<std::__1::basic_ostream<char, std::__1::char_traits<char> >::char_type,
      std::__1::basic_ostream<char, std::__1::char_traits<char> >::traits_type> *' (aka 'basic_streambuf<char, std::__1::char_traits<char> > *') for
      1st argument
    basic_ostream& operator<<(basic_streambuf<char_type, traits_type>* __sb);
                   ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:755:1: note: candidate function not viable: no known conversion from 'const boost::gregorian::date'
      to 'char' for 2nd argument
operator<<(basic_ostream<_CharT, _Traits>& __os, char __cn)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:788:1: note: candidate function not viable: no known conversion from 'const boost::gregorian::date'
      to 'char' for 2nd argument
operator<<(basic_ostream<char, _Traits>& __os, char __c)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:795:1: note: candidate function not viable: no known conversion from 'const boost::gregorian::date'
      to 'signed char' for 2nd argument
operator<<(basic_ostream<char, _Traits>& __os, signed char __c)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:802:1: note: candidate function not viable: no known conversion from 'const boost::gregorian::date'
      to 'unsigned char' for 2nd argument
operator<<(basic_ostream<char, _Traits>& __os, unsigned char __c)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:816:1: note: candidate function not viable: no known conversion from 'const boost::gregorian::date'
      to 'const char *' for 2nd argument
operator<<(basic_ostream<_CharT, _Traits>& __os, const char* __strn)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:862:1: note: candidate function not viable: no known conversion from 'const boost::gregorian::date'
      to 'const char *' for 2nd argument
operator<<(basic_ostream<char, _Traits>& __os, const char* __str)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:869:1: note: candidate function not viable: no known conversion from 'const boost::gregorian::date'
      to 'const signed char *' for 2nd argument
operator<<(basic_ostream<char, _Traits>& __os, const signed char* __str)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:877:1: note: candidate function not viable: no known conversion from 'const boost::gregorian::date'
      to 'const unsigned char *' for 2nd argument
operator<<(basic_ostream<char, _Traits>& __os, const unsigned char* __str)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:1061:1: note: candidate function not viable: no known conversion from
      'const boost::gregorian::date' to 'const std::__1::error_code' for 2nd argument
operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __ec)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:748:1: note: candidate template ignored: deduced conflicting types for parameter '_CharT'
      ('char' vs. 'boost::gregorian::date')
operator<<(basic_ostream<_CharT, _Traits>& __os, _CharT __c)
^
/usr/local/include/boost/smart_ptr/shared_ptr.hpp:991:64: note: candidate template ignored: could not match 'shared_ptr<type-parameter-0-2>' against
      'const boost::gregorian::date'
template<class E, class T, class Y> std::basic_ostream<E, T> & operator<< (std::basic_ostream<E, T> & os, shared_ptr<Y> const & p)
                                                               ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:809:1: note: candidate template ignored: could not match 'const _CharT *' against
      'boost::gregorian::date'
operator<<(basic_ostream<_CharT, _Traits>& __os, const _CharT* __str)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:1044:1: note: candidate template ignored: could not match 'basic_string<type-parameter-0-0,
      type-parameter-0-1, type-parameter-0-2>' against 'const boost::gregorian::date'
operator<<(basic_ostream<_CharT, _Traits>& __os,
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:1069:1: note: candidate template ignored: could not match 'shared_ptr<type-parameter-0-2>' against
      'const boost::gregorian::date'
operator<<(basic_ostream<_CharT, _Traits>& __os, shared_ptr<_Yp> const& __p)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:1090:1: note: candidate template ignored: could not match 'bitset<_Size>' against
      'const boost::gregorian::date'
operator<<(basic_ostream<_CharT, _Traits>& __os, const bitset<_Size>& __x)
^
/usr/local/include/boost/test/utils/wrap_stringstream.hpp:64:1: note: candidate template ignored: could not match 'basic_wrap_stringstream' against
      'basic_ostream'
operator<<( basic_wrap_stringstream<CharT>& targ, T const& t )
^
/usr/local/include/boost/test/utils/wrap_stringstream.hpp:109:1: note: candidate template ignored: could not match 'basic_wrap_stringstream' against
      'basic_ostream'
operator<<( basic_wrap_stringstream<CharT>& targ, basic_wrap_stringstream<CharT>& src )
^
/usr/local/include/boost/test/utils/wrap_stringstream.hpp:121:1: note: candidate template ignored: could not match 'basic_wrap_stringstream' against
      'basic_ostream'
operator<<( basic_wrap_stringstream<CharT>& targ, std::ios_base& (BOOST_TEST_CALL_DECL *man)(std::ios_base&) )
^
/usr/local/include/boost/test/utils/wrap_stringstream.hpp:131:1: note: candidate template ignored: could not match 'basic_wrap_stringstream' against
      'basic_ostream'
operator<<( basic_wrap_stringstream<CharT>& targ, std::basic_ostream<Elem,Tr>& (BOOST_TEST_CALL_DECL *man)(std::basic_ostream<Elem, Tr>&) )
^
/usr/local/include/boost/test/utils/wrap_stringstream.hpp:141:1: note: candidate template ignored: could not match 'basic_wrap_stringstream' against
      'basic_ostream'
operator<<( basic_wrap_stringstream<CharT>& targ, std::basic_ios<Elem, Tr>& (BOOST_TEST_CALL_DECL *man)(std::basic_ios<Elem, Tr>&) )
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:1034:1: note: candidate template ignored: requirement '!is_lvalue_reference<basic_ostream<char>
      &>::value' was not satisfied [with _Stream = std::__1::basic_ostream<char> &, _Tp = boost::gregorian::date]
operator<<(_Stream&& __os, const _Tp& __x)
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:1052:1: note: candidate template ignored: could not match 'basic_string_view<type-parameter-0-0,
      type-parameter-0-1>' against 'boost::gregorian::date'
operator<<(basic_ostream<_CharT, _Traits>& __os,
^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/ostream:1082:1: note: candidate template ignored: could not match 'unique_ptr<type-parameter-0-2,
      type-parameter-0-3>' against 'const boost::gregorian::date'
operator<<(basic_ostream<_CharT, _Traits>& __os, unique_ptr<_Yp, _Dp> const& __p)
^
/usr/local/include/boost/date_time/int_adapter.hpp:463:3: note: candidate template ignored: could not match 'int_adapter<type-parameter-0-2>' against
      'const boost::gregorian::date'
  operator<<(std::basic_ostream<charT, traits>& os, const int_adapter<int_type>& ia)
  ^
/usr/local/Cellar/llvm/6.0.1/include/c++/v1/complex:1431:1: note: candidate template ignored: could not match 'complex<type-parameter-0-0>' against
      'const boost::gregorian::date'
operator<<(basic_ostream<_CharT, _Traits>& __os, const complex<_Tp>& __x)
^
2 errors generated.
make[2]: *** [CMakeFiles/meetup.dir/meetup_test.cpp.o] Error 1
make[1]: *** [CMakeFiles/meetup.dir/all] Error 2
make: *** [all] Error 2

[arcuru]

I've been against this in the past (since you have to put in real effort to write an implementation that actually needs this include in the test suite), but given how many issues we've seen with people hitting initial compile problems withmeetup and gigasecond (See #201, #142, #149, #150) I'm going to stop being stubborn and just merge it.