~LogCapture() should be noexcept (false) ?

[ripopov]

In a g3log.hpp I read:

// 'Design By Contract' stream API. For Broken Contracts:
// unit testing: it will throw std::runtime_error when a contract breaks
// I.R.L : it will exit the application by using fatal signal SIGABRT

So my understanding is that for unit testing I can install setFatalPreLoggingHook that will throw, so I can unit-test contracts with EXPECT_THROW(). However LogCapture() destructor is noexcept (by default), so any attempt to throw from CHECK() will lead to std::terminate.

[KjellKod]

Hi,

g3log uses SIGABRT for exiting when a failed contract is discovered.
For unit testing you can replace the default fatal handling with a custom one using

g3log/src/g3log.cpp

Line 110 in a6788f8

/** REPLACE fatalCallToLogger for fatalCallForUnitTest

using: setFatalExitHandler(...)

You can see test_io.cpp which does this frequently using RestoreFileLogger::RestoreFileLogger(...) which sets this.

g3log/test_unit/testing_helpers.cpp

Line 117 in a6788f8

setFatalExitHandler(&mockFatalCall);

[KjellKod]

The setFatalPreLoggingHook was added by community request to trigger specific actions before going into the fatal handling. It's the setFatalExitHandler that you are after for unit testing.

[ripopov]

In either case it will be called from destructor, so

g3::setFatalExitHandler([](g3::FatalMessagePtr){
    throw std::runtime_error("unit test exception");
});

will also lead to abort.

So I don't think those comments in source code are correct:

// 'Design By Contract' stream API. For Broken Contracts:
//         unit testing: it will throw std::runtime_error when a contract breaks
//         I.R.L : it will exit the application by using fatal signal SIGABRT
#define CHECK(boolean_expression)        \

// Design By Contract, printf-like API syntax with variadic input parameters.
// Throws std::runtime_eror if contract breaks
#define CHECKF(boolean_expression, printf_like_message, ...)    \

// Backwards compatible. The same as CHECKF.
// Design By Contract, printf-like API syntax with variadic input parameters.
// Throws std::runtime_eror if contract breaks
#define CHECK_F(boolean_expression, printf_like_message, ...)    \

[KjellKod]

Check the test_io.cpp . I'm running many, many tests with FATAL LOG calls and CHECK(...)

[KjellKod]

You are correct that the code comment should be updated.
With the information I have provided you should be able to run your own unit tests

[ripopov]

Sorry, I still don't get it, probably I've missing something. I've checked test_io.cpp and I don't see EXPECT_THROW tests there, instead mock installs fatal handler that will push message to logger but will allow code with broken invariant to continue.

[ripopov]

I think throwing exception from CHECK, as comments suggest is a good idea for unit testing.

[KjellKod]

As it’s currently implemented that’s not how it’s done. I’ve provided the pattern for verifying failed CHECK.

If that doesn’t work for your requirements then please provide a PR that targets your concerns and I will take it under evaluation