#include "doctest/doctest.h" #include "misc/TestUtilities.h" #include "quill/Backend.h" #include "quill/Frontend.h" #include "quill/LogMacros.h" #include "quill/sinks/FileSink.h" #include #include #include using namespace quill; /***/ TEST_CASE("log_arguments_evaluation") { static constexpr char const* filename = "log_arguments_evaluation.log"; // Start the logging backend thread Backend::start(); Frontend::preallocate(); // Set writing logging to a file auto file_sink = Frontend::create_or_get_sink( filename, []() { FileSinkConfig cfg; cfg.set_open_mode('w'); return cfg; }(), FileEventNotifier{}); std::string const logger_name = "logger"; Logger* logger = Frontend::create_or_get_logger(logger_name, std::move(file_sink)); size_t cnt{0}; auto arg_str = [&cnt]() { ++cnt; return "expensive_calculation"; }; // 1. checks that log arguments are not evaluated when we don't log logger->set_log_level(quill::LogLevel::Info); LOG_DEBUG(logger, "Test log arguments {}", arg_str()); LOG_TRACE_L1(logger, "Test log arguments {}", arg_str()); REQUIRE_EQ(cnt, 0); // 2. checks that log arguments are evaluated only once per log statement LOG_INFO(logger, "Test log arguments {}", arg_str()); REQUIRE_EQ(cnt, 1); logger->flush_log(); Frontend::remove_logger(logger); // Wait until the backend thread stops for test stability Backend::stop(); // Read file and check std::vector const file_contents = quill::testing::file_contents(filename); REQUIRE_EQ(file_contents.size(), 1); testing::remove_file(filename); }