No QOS operator<< / GMock no match for operator<<

[NoeSechet]

Hi!

Were are trying to test our application with GTest and its mocking feature.

We would get the following error:

/home/n.sechet/{....}/include/gtest/gtest-printers.h:291:36: error: no matching function for call to ‘testing::internal::internal_stream_operator_without_lexical_name_lookup::StreamPrinter::PrintValue(const dds::core::TEntityQos<org::eclipse::cyclonedds::pub::qos::PublisherQosDelegate>&, std::nullptr_t)’
     T, decltype(Printer::PrintValue(std::declval<const T&>(), nullptr)),
                 ~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/n.sechet/{....}/include/gtest/gtest-printers.h:212:15: note: candidate: template<class T, class, class> static void testing::internal::internal_stream_operator_without_lexical_name_lookup::StreamPrinter::PrintValue(const T&, std::ostream*)
   static void PrintValue(const T& value, ::std::ostream* os) {
               ^~~~~~~~~~
/home/n.sechet/{....}/include/gtest/gtest-printers.h:212:15: note:   template argument deduction/substitution failed:
/home/n.sechet/{....}/include/gtest/gtest-printers.h:211:33: error: no match for ‘operator<<’ (operand types are ‘std::basic_ostream<char>’ and ‘const dds::core::TEntityQos<org::eclipse::cyclonedds::pub::qos::PublisherQosDelegate>’)
             typename = decltype(std::declval<std::ostream&>()
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                                 << std::declval<const T&>())>
                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~

We believe it's because in the current QOS classes do not overwrite the operator<<, which the GTest library uses in the background.

Is there any plan to overwrite more operators in the QOS classes?

Thank you for your work

[eboasson]

I am afraid I don't feel qualified to answer this question (too C++-y for me). @e-hndrks does this sounds like a feasible extension, would it run into other ways in which << is already used for QoS's, or is there some other reason to think we may come to regret it if we do this?