Mostly a refactor of tests (#513)

.vscode/launch.json

@@ -12,10 +12,9 @@
             "name": "(gdb) Start",
             "type": "cppdbg",
             "request": "launch",
-            "program": "${workspaceFolder}/build/g3log-FATAL-contract",
+            "program": "${workspaceFolder}/build/test_signal",
             "MIMode": "gdb",
-            "cwd": "${workspaceFolder}/build"
+            "cwd": "${workspaceFolder}/build""setupCommands": [
-            "setupCommands": [
                 {
                     "description": "Enable pretty-printing for gdb",
                     "text": "-enable-pretty-printing",
@@ -28,6 +27,5 @@
                 }
             ]
         }
-
     ]
 }

.vscode/settings.json

@@ -1,4 +1,7 @@
 {
     "cmake.configureOnOpen": false,
-    "editor.formatOnSave": true
+    "editor.formatOnSave": true,
-}
+    "files.associations": {
+        "ostream": "cpp"
+    }
+}

src/crashhandler_unix.cpp

@@ -242,6 +242,30 @@ namespace g3 {
          exit(signal_number);
       }
 
+      // This function is intended to be async-signal-safe. Using write and STDERR_FILENO should be
+      // safe in a signal handler. ref: http://pubs.opengroup.org/onlinepubs/009695399/functions/write.html
+
+      // This function is intended to be async-signal-safe.
+      // It writes an error message to stderr using the write system call,
+      // which is listed as async-signal-safe by POSIX.
+      size_t writeErrorMessage(const char* message) {
+         if (message == nullptr) {
+            return 0;
+         }
+
+         // Calculate the length of the message without using std library strlen or similar
+         // this is to ensure async-signal-safe by POSIX
+         size_t length = 0;
+         for (const char* p = message; *p != '\0'; ++p) {
+            ++length;
+         }
+
+         // Write the message to STDERR_FILENO in a single call.
+         // This assumes that the message is not too large for a single write.
+         auto bytes_written = write(STDERR_FILENO, message, length);
+         return bytes_written;
+      }
+
       // restores the signal handler back to default
       void restoreFatalHandlingToDefault() {
 #if !(defined(DISABLE_FATAL_SIGNALHANDLING))
@@ -274,7 +298,8 @@ namespace g3 {
 
       if (sigaction(signal_number, &(old_action_it->second), nullptr) < 0) {
          auto signalname = std::string("sigaction - ") + signalToStr(signal_number);
-         perror(signalname.c_str());
+         // https://man7.org/linux/man-pages/man7/signal-safety.7.html (see signal-safety)
+         internal::writeErrorMessage(signalname.c_str());
       }
 
       gSavedSigActions.erase(old_action_it);

src/crashhandler_windows.cpp

@@ -14,6 +14,7 @@
 #include <windows.h>
 #include <atomic>
 #include <csignal>
+#include <cstring>
 #include <sstream>
 #include "g3log/crashhandler.hpp"
 #include "g3log/g3log.hpp"
@@ -171,6 +172,13 @@ namespace g3 {
          raise(signal_number);
       }
 
+      // FYI: Concept of async-signal-safe operations does not exist on windows
+      // we stick to perror for lack of better alternatives.
+      size_t writeErrorMessage(const char* message) {
+         perror(message);
+         return std::strlen(message);
+      }
+
       // Restore back to default fatal event handling
       void restoreFatalHandlingToDefault() {
 #if !(defined(DISABLE_FATAL_SIGNALHANDLING))
@@ -181,19 +189,19 @@ namespace g3 {
 #endif
 
          if (SIG_ERR == signal(SIGABRT, SIG_DFL))
-            perror("signal - SIGABRT");
+            internal::writeErrorMessage("signal - SIGABRT");
 
          if (SIG_ERR == signal(SIGFPE, SIG_DFL))
-            perror("signal - SIGABRT");
+            internal::writeErrorMessage("signal - SIGABRT");
 
          if (SIG_ERR == signal(SIGSEGV, SIG_DFL))
-            perror("signal - SIGABRT");
+            internal::writeErrorMessage("signal - SIGABRT");
 
          if (SIG_ERR == signal(SIGILL, SIG_DFL))
-            perror("signal - SIGABRT");
+            internal::writeErrorMessage("signal - SIGABRT");
 
          if (SIG_ERR == signal(SIGTERM, SIG_DFL))
-            perror("signal - SIGABRT");
+            internal::writeErrorMessage("signal - SIGABRT");
 #endif
       }
 
@@ -212,15 +220,15 @@ namespace g3 {
       if (!g_installed_thread_signal_handler) {
          g_installed_thread_signal_handler = true;
          if (SIG_ERR == signal(SIGTERM, signalHandler))
-            perror("signal - SIGTERM");
+            internal::writeErrorMessage("signal - SIGTERM");
          if (SIG_ERR == signal(SIGABRT, signalHandler))
-            perror("signal - SIGABRT");
+            internal::writeErrorMessage("signal - SIGABRT");
          if (SIG_ERR == signal(SIGFPE, signalHandler))
-            perror("signal - SIGFPE");
+            internal::writeErrorMessage("signal - SIGFPE");
          if (SIG_ERR == signal(SIGSEGV, signalHandler))
-            perror("signal - SIGSEGV");
+            internal::writeErrorMessage("signal - SIGSEGV");
          if (SIG_ERR == signal(SIGILL, signalHandler))
-            perror("signal - SIGILL");
+            internal::writeErrorMessage("signal - SIGILL");
       }
 #endif
    }

src/g3log.cpp

@@ -148,13 +148,13 @@ namespace g3 {
          message.get()->setExpression(boolean_expression);
 
          if (internal::wasFatal(level)) {
-            saveFatalMessage(level, stack_trace, message, fatal_signal);
+            saveFatalMessage(stack_trace, message, fatal_signal);
          } else {
             pushMessageToLogger(message);
          }
       }
 
-      void saveFatalMessage(const LEVELS& level, const char* stack_trace, g3::LogMessagePtr& message, int& fatal_signal) {
+      void saveFatalMessage(const char* stack_trace, g3::LogMessagePtr& message, int& fatal_signal) {
          auto fatalhook = g_fatal_pre_logging_hook;
          // In case the fatal_pre logging actually will cause a crash in its turn
          // let's not do recursive crashing!

src/g3log/crashhandler.hpp

@@ -77,5 +77,6 @@ namespace g3 {
        * This is an internal only function. Do not use it elsewhere. It is triggered
        * from g3log, g3LogWorker after flushing messages to file */
       void exitWithDefaultSignalHandler(const LEVELS& level, g3::SignalType signal_number);
+      size_t writeErrorMessage(const char* message);
    }  // namespace internal
 }  // namespace g3

src/g3log/g3log.hpp

@@ -106,7 +106,7 @@ namespace g3 {
       void saveMessage(const char* message, const char* file, int line, const char* function, const LEVELS& level,
                        const char* boolean_expression, int fatal_signal, const char* stack_trace);
 
-      void saveFatalMessage(const LEVELS& level, const char* stack_trace, g3::LogMessagePtr& message, int& fatal_signal);
+      void saveFatalMessage(const char* stack_trace, g3::LogMessagePtr& message, int& fatal_signal);
 
       // forwards the message to all sinks
       void pushMessageToLogger(LogMessagePtr log_entry);

test_unit/Test.cmake

@@ -62,7 +62,7 @@
         SET(OS_SPECIFIC_TEST test_crashhandler_windows)
      ENDIF(MSVC OR MINGW)
 
-      SET(tests_to_run test_message test_filechange test_io test_cpp_future_concepts test_concept_sink test_sink ${OS_SPECIFIC_TEST})
+      SET(tests_to_run test_message test_filechange test_io test_fatal test_signal test_cpp_future_concepts test_concept_sink test_sink ${OS_SPECIFIC_TEST})
       SET(helper ${DIR_UNIT_TEST}/testing_helpers.h ${DIR_UNIT_TEST}/testing_helpers.cpp)
       include_directories(${DIR_UNIT_TEST})
 

test_unit/test_fatal.cpp

@@ -0,0 +1,349 @@
+/** ==========================================================================re
+ * 2011 by KjellKod.cc. This is PUBLIC DOMAIN to use at your own risk and comes
+ * with no warranties. This code is yours to share, use and modify with no
+ * strings attached and no restrictions or obligations.
+ *
+ * For more information see g3log/LICENSE or refer refer to http://unlicense.org
+ * ============================================================================*/
+
+#include <gtest/gtest.h>
+#include "g3log/g3log.hpp"
+#include "g3log/generated_definitions.hpp"
+#include "g3log/loglevels.hpp"
+#include "g3log/logworker.hpp"
+#include "testing_helpers.h"
+
+#include <algorithm>
+#include <chrono>
+#include <cstdio>
+#include <exception>
+#include <iomanip>
+#include <memory>
+#include <string>
+#include <thread>
+
+namespace {
+   const std::string log_directory = "./";
+   const std::string t_info = "test INFO ";
+   const std::string t_info2 = "test INFO 123";
+   const std::string t_debug = "test DEBUG ";
+   const std::string t_debug3 = "test DEBUG 1.123456";
+   const std::string t_warning = "test WARNING ";
+   const std::string t_warning3 = "test WARNING yello";
+
+   std::atomic<size_t> g_fatal_counter = {0};
+   void fatalCounter() {
+      ++g_fatal_counter;
+   }
+
+}  // end anonymous namespace
+
+using namespace testing_helpers;
+TEST(LogTest, LOGF__FATAL) {
+   RestoreFileLogger logger(log_directory);
+   ASSERT_FALSE(mockFatalWasCalled());
+   LOGF(FATAL, "This message should throw %d", 0);
+   EXPECT_TRUE(mockFatalWasCalled());
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "This message should throw 0")) << "\n****" << mockFatalMessage();
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "FATAL"));
+
+   auto file_content = logger.resetAndRetrieveContent();
+   EXPECT_TRUE(verifyContent(file_content, "This message should throw 0")) << "\n****" << file_content;
+   EXPECT_TRUE(verifyContent(file_content, "FATAL"));
+}
+
+#ifndef DISABLE_FATAL_SIGNALHANDLING
+
+TEST(LogTest, FatalSIGTERM__UsingDefaultHandler) {
+   RestoreFileLogger logger(log_directory);
+   g_fatal_counter.store(0);
+   g3::setFatalPreLoggingHook(fatalCounter);
+   raise(SIGTERM);
+   logger.reset();
+   EXPECT_EQ(g_fatal_counter.load(), size_t{1});
+}
+
+#if !(defined(WIN32) || defined(_WIN32) || defined(__WIN32__))
+namespace {
+   std::atomic<size_t> customFatalCounter = {0};
+   std::atomic<int> lastEncounteredSignal = {0};
+   void customSignalHandler(int signal_number, siginfo_t* info, void* unused_context) {
+      lastEncounteredSignal.store(signal_number);
+      ++customFatalCounter;
+   }
+   void installCustomSIGTERM() {
+      struct sigaction action;
+      memset(&action, 0, sizeof(action));
+      sigemptyset(&action.sa_mask);
+      action.sa_sigaction = &customSignalHandler;
+      action.sa_flags = SA_SIGINFO;
+      sigaction(SIGTERM, &action, nullptr);
+   }
+
+   std::atomic<bool> oldSigTermCheck = {false};
+   void customOldSignalHandler(int signal_number, siginfo_t* info, void* unused_context) {
+      lastEncounteredSignal.store(signal_number);
+      oldSigTermCheck.store(true);
+   }
+   void installCustomOldSIGTERM() {
+      struct sigaction action;
+      memset(&action, 0, sizeof(action));
+      sigemptyset(&action.sa_mask);
+      action.sa_sigaction = &customOldSignalHandler;
+      action.sa_flags = SA_SIGINFO;
+      sigaction(SIGTERM, &action, nullptr);
+   }
+
+}  // namespace
+
+// Override of signal handling and testing of it should be fairly easy to port to windows
+// ref: https://github.com/KjellKod/g3log/blob/master/src/crashhandler_windows.cpp
+// what is missing is the override of signals and custom installation of signals
+// ref: https://github.com/KjellKod/g3log/blob/master/src/crashhandler_unix.cpp
+//      functions: void restoreFatalHandlingToDefault()
+//                 void overrideSetupSignals(const std::map<int, std::string> overrideSignals)
+//                 void restoreSignalHandler(int signal_number)
+//
+// It would require some adding of unit test (see the test below)
+// and good Windows experience. Since I am not currently working much on the Windows
+// side I am reaching out to the community for this one:
+//
+//
+// For the test to work the following code should be added in this test
+//void customSignalHandler(int signal_number) {
+//	lastEncounteredSignal.store(signal_number);
+//	++customFatalCounter;
+//}
+//
+//void installCustomSIGTERM() {
+//	ASSERT_TRUE(SIG_ERR != signal(SIGTERM, customSignalHandler));
+//}
+
+TEST(LogTest, FatalSIGTERM__UsingCustomHandler) {
+   RestoreFileLogger logger(log_directory);
+   g_fatal_counter.store(0);
+   g3::setFatalPreLoggingHook(fatalCounter);
+   installCustomSIGTERM();
+   g3::overrideSetupSignals({{SIGABRT, "SIGABRT"}, {SIGFPE, "SIGFPE"}, {SIGILL, "SIGILL"}});
+
+   installCustomSIGTERM();
+   EXPECT_EQ(customFatalCounter.load(), size_t{0});
+   EXPECT_EQ(lastEncounteredSignal.load(), 0);
+
+   raise(SIGTERM);
+   logger.reset();
+   EXPECT_EQ(g_fatal_counter.load(), size_t{0});
+   EXPECT_EQ(lastEncounteredSignal.load(), SIGTERM);
+   EXPECT_EQ(customFatalCounter.load(), size_t{1});
+}
+
+TEST(LogTest, FatalSIGTERM__VerifyingOldCustomHandler) {
+   RestoreFileLogger logger(log_directory);
+   g_fatal_counter.store(0);
+   customFatalCounter.store(0);
+   lastEncounteredSignal.store(0);
+
+   g3::setFatalPreLoggingHook(fatalCounter);
+   installCustomOldSIGTERM();
+   g3::overrideSetupSignals({{SIGABRT, "SIGABRT"}, {SIGFPE, "SIGFPE"}, {SIGILL, "SIGILL"}, {SIGTERM, "SIGTERM"}});
+   g3::restoreSignalHandler(SIGTERM);  // revert SIGTERM installation
+
+   EXPECT_EQ(customFatalCounter.load(), size_t{0});
+   EXPECT_EQ(lastEncounteredSignal.load(), 0);
+   EXPECT_FALSE(oldSigTermCheck.load());
+   raise(SIGTERM);
+   logger.reset();
+   EXPECT_EQ(g_fatal_counter.load(), size_t{0});
+   EXPECT_EQ(lastEncounteredSignal.load(), SIGTERM);
+   EXPECT_TRUE(oldSigTermCheck.load());
+}
+
+#endif  // DISABLE_FATAL_SIGNALHANDLING
+#endif  // !(defined(WIN32) || defined(_WIN32) || defined(__WIN32__))
+
+TEST(LogTest, LOG_preFatalLogging_hook) {
+   {
+      RestoreFileLogger logger(log_directory);
+      ASSERT_FALSE(mockFatalWasCalled());
+      g_fatal_counter.store(0);
+      g3::setFatalPreLoggingHook(fatalCounter);
+      LOG(FATAL) << "This message is fatal";
+      logger.reset();
+      EXPECT_EQ(g_fatal_counter.load(), size_t{1});
+   }
+   {
+      // Now with no fatal pre-logging-hook
+      RestoreFileLogger logger(log_directory);
+      ASSERT_FALSE(mockFatalWasCalled());
+      g_fatal_counter.store(0);
+      LOG(FATAL) << "This message is fatal";
+      EXPECT_EQ(g_fatal_counter.load(), size_t{0});
+   }
+}
+
+TEST(LogTest, LOG_FATAL) {
+   RestoreFileLogger logger(log_directory);
+   ASSERT_FALSE(mockFatalWasCalled());
+
+   LOG(FATAL) << "This message is fatal";
+   EXPECT_TRUE(mockFatalWasCalled());
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "This message is fatal"))
+      << "\ncontent: [[" << mockFatalMessage() << "]]";
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "FATAL"));
+
+   logger.reset();
+   std::string file_content = readFileToText(logger.logFile());
+   EXPECT_TRUE(verifyContent(file_content, "This message is fatal"));
+   EXPECT_TRUE(verifyContent(file_content, "FATAL"));
+   EXPECT_TRUE(verifyContent(file_content, "EXIT trigger caused by "));
+}
+TEST(LogTest, LOGF_IF__FATAL) {
+   RestoreFileLogger logger(log_directory);
+   EXPECT_FALSE(mockFatalWasCalled());
+   LOGF_IF(FATAL, (2 < 3), "This message %s be worse", "could");
+   EXPECT_TRUE(mockFatalWasCalled());
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by ")) << "\n"
+                                                                             << mockFatalMessage();
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "FATAL"));
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "This message could be worse"));
+
+   logger.reset();
+   std::string file_content = readFileToText(logger.logFile());
+   EXPECT_TRUE(verifyContent(file_content, "EXIT trigger caused by "));
+   EXPECT_TRUE(verifyContent(file_content, "FATAL"));
+   EXPECT_TRUE(verifyContent(file_content, "This message could be worse"));
+}
+TEST(LogTest, LOG_IF__FATAL) {
+   RestoreFileLogger logger(log_directory);
+   LOG_IF(WARNING, (0 != t_info.compare(t_info))) << "This message should NOT be written";
+   EXPECT_FALSE(mockFatalWasCalled());
+   LOG_IF(FATAL, (0 != t_info.compare(t_info2))) << "This message should throw. xyz ";
+   EXPECT_TRUE(mockFatalWasCalled());
+
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "FATAL"));
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "This message should throw. xyz "));
+
+   logger.reset();
+   std::string file_content = readFileToText(logger.logFile());
+   EXPECT_TRUE(verifyContent(file_content, "EXIT trigger caused by "));
+   EXPECT_TRUE(verifyContent(file_content, "FATAL"));
+   EXPECT_TRUE(verifyContent(file_content, "This message should throw. xyz "));
+}
+TEST(LogTest, LOG_IF__FATAL__NO_THROW) {
+   RestoreFileLogger logger(log_directory);
+   LOG_IF(FATAL, (2 > 3)) << "This message%sshould NOT throw";
+   ASSERT_FALSE(mockFatalWasCalled());
+}
+
+// CHECK_F
+TEST(CheckTest, CHECK_F__thisWILL_PrintErrorMsg) {
+   RestoreFileLogger logger(log_directory);
+   EXPECT_TRUE(mockFatalMessage().empty());
+   EXPECT_FALSE(mockFatalWasCalled());
+
+   CHECK(1 == 2);
+   EXPECT_FALSE(mockFatalMessage().empty());
+   EXPECT_TRUE(mockFatalWasCalled());
+
+   logger.reset();
+   std::string file_content = readFileToText(logger.logFile());
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
+   EXPECT_TRUE(verifyContent(file_content, "CONTRACT")) << "**** " << mockFatalMessage();
+}
+
+TEST(CHECK_F_Test, CHECK_F__thisWILL_PrintErrorMsg) {
+   RestoreFileLogger logger(log_directory);
+   std::string msg = "This message is added to throw %s and %s";
+   std::string arg1 = "message";
+   std::string arg3 = "log";
+
+   CHECK_F(1 >= 2, msg.c_str(), arg1.c_str(), arg3.c_str());
+   logger.reset();
+   std::string file_content = readFileToText(logger.logFile());
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
+   EXPECT_TRUE(verifyContent(file_content, "CONTRACT"));
+}
+
+TEST(CHECK_Test, CHECK__thisWILL_PrintErrorMsg) {
+   RestoreFileLogger logger(log_directory);
+   std::string msg = "This message is added to throw message and log";
+   CHECK(1 >= 2) << msg;
+
+   logger.reset();
+   std::string file_content = readFileToText(logger.logFile());
+   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
+   EXPECT_TRUE(verifyContent(file_content, "CONTRACT"));
+   EXPECT_TRUE(verifyContent(file_content, msg));
+}
+TEST(CHECK, CHECK_ThatWontThrow) {
+   RestoreFileLogger logger(log_directory);
+   std::string msg = "This %s should never appear in the %s";
+   std::string msg3 = "This message should never appear in the log";
+   CHECK(1 == 1);
+   CHECK_F(1 == 1, msg.c_str(), "message", "log");
+   logger.reset();
+   EXPECT_FALSE(mockFatalWasCalled());
+
+   std::string file_content = readFileToText(logger.logFile());
+   EXPECT_FALSE(verifyContent(file_content, msg3));
+   EXPECT_FALSE(verifyContent(mockFatalMessage(), msg3));
+}
+
+TEST(CHECK, CHECK_runtimeError) {
+   RestoreFileLogger logger(log_directory);
+
+   g3::setFatalExitHandler([](g3::FatalMessagePtr msg) {
+      throw std::runtime_error("fatal test handler");
+   });
+
+   class dynamic_int_array {
+      std::unique_ptr<int[]> data_;
+      const int size_;
+
+     public:
+      explicit dynamic_int_array(int size) :
+          data_{std::make_unique<int[]>(size)},
+          size_(size) {}
+
+      int& at(int i) {
+         CHECK(i < size_);
+
+         // unreachable if i >= size_
+         return data_[i];
+      }
+   };
+
+   dynamic_int_array arr{3};
+
+   EXPECT_THROW(arr.at(3) = 1, std::runtime_error);
+}
+
+// see also test_io -- AddNonFatal
+TEST(CustomLogLevels, AddFatal) {
+   RestoreFileLogger logger(log_directory);
+   const LEVELS DEADLY{FATAL.value + 1, {"DEADLY"}};
+   EXPECT_TRUE(g3::internal::wasFatal(DEADLY));
+   g_fatal_counter.store(0);
+   ASSERT_FALSE(mockFatalWasCalled());
+   g3::setFatalPreLoggingHook(fatalCounter);
+#ifdef G3_DYNAMIC_LOGGING
+   g3::only_change_at_initialization::addLogLevel(DEADLY, true);
+#endif
+   // clang-format off
+   LOG(DEADLY) << "Testing my own custom level"; auto line = __LINE__;
+   // clang-format on
+   logger.reset();
+   ASSERT_TRUE(mockFatalWasCalled());
+   EXPECT_EQ(size_t{1}, g_fatal_counter.load());
+
+   std::string file_content = readFileToText(logger.logFile());
+   std::string expected;
+   expected += "DEADLY [test_fatal.cpp->" + std::string(G3LOG_PRETTY_FUNCTION) + ":" + std::to_string(line);
+   EXPECT_TRUE(verifyContent(file_content, expected)) << file_content
+                                                      << "\n\nExpected: \n"
+                                                      << expected;
+   g_fatal_counter.store(0);  // restore
+}

test_unit/test_io.cpp

@@ -327,288 +327,6 @@ TEST(LogTest, LOG_IF) {
    EXPECT_TRUE(verifyContent(file_content, t_info2));
    EXPECT_FALSE(verifyContent(file_content, t_debug3));
 }
-TEST(LogTest, LOGF__FATAL) {
-   RestoreFileLogger logger(log_directory);
-   ASSERT_FALSE(mockFatalWasCalled());
-   LOGF(FATAL, "This message should throw %d", 0);
-   EXPECT_TRUE(mockFatalWasCalled());
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "This message should throw 0")) << "\n****" << mockFatalMessage();
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "FATAL"));
-
-   auto file_content = logger.resetAndRetrieveContent();
-   EXPECT_TRUE(verifyContent(file_content, "This message should throw 0")) << "\n****" << file_content;
-   EXPECT_TRUE(verifyContent(file_content, "FATAL"));
-}
-
-#ifndef DISABLE_FATAL_SIGNALHANDLING
-
-TEST(LogTest, FatalSIGTERM__UsingDefaultHandler) {
-   RestoreFileLogger logger(log_directory);
-   g_fatal_counter.store(0);
-   g3::setFatalPreLoggingHook(fatalCounter);
-   raise(SIGTERM);
-   logger.reset();
-   EXPECT_EQ(g_fatal_counter.load(), size_t{1});
-}
-
-#if !(defined(WIN32) || defined(_WIN32) || defined(__WIN32__))
-namespace {
-   std::atomic<size_t> customFatalCounter = {0};
-   std::atomic<int> lastEncounteredSignal = {0};
-   void customSignalHandler(int signal_number, siginfo_t* info, void* unused_context) {
-      lastEncounteredSignal.store(signal_number);
-      ++customFatalCounter;
-   }
-   void installCustomSIGTERM() {
-      struct sigaction action;
-      memset(&action, 0, sizeof(action));
-      sigemptyset(&action.sa_mask);
-      action.sa_sigaction = &customSignalHandler;
-      action.sa_flags = SA_SIGINFO;
-      sigaction(SIGTERM, &action, nullptr);
-   }
-
-   std::atomic<bool> oldSigTermCheck = {false};
-   void customOldSignalHandler(int signal_number, siginfo_t* info, void* unused_context) {
-      lastEncounteredSignal.store(signal_number);
-      oldSigTermCheck.store(true);
-   }
-   void installCustomOldSIGTERM() {
-      struct sigaction action;
-      memset(&action, 0, sizeof(action));
-      sigemptyset(&action.sa_mask);
-      action.sa_sigaction = &customOldSignalHandler;
-      action.sa_flags = SA_SIGINFO;
-      sigaction(SIGTERM, &action, nullptr);
-   }
-
-}  // namespace
-
-// Override of signal handling and testing of it should be fairly easy to port to windows
-// ref: https://github.com/KjellKod/g3log/blob/master/src/crashhandler_windows.cpp
-// what is missing is the override of signals and custom installation of signals
-// ref: https://github.com/KjellKod/g3log/blob/master/src/crashhandler_unix.cpp
-//      functions: void restoreFatalHandlingToDefault()
-//                 void overrideSetupSignals(const std::map<int, std::string> overrideSignals)
-//                 void restoreSignalHandler(int signal_number)
-//
-// It would require some adding of unit test (see the test below)
-// and good Windows experience. Since I am not currently working much on the Windows
-// side I am reaching out to the community for this one:
-//
-//
-// For the test to work the following code should be added in this test
-//void customSignalHandler(int signal_number) {
-//	lastEncounteredSignal.store(signal_number);
-//	++customFatalCounter;
-//}
-//
-//void installCustomSIGTERM() {
-//	ASSERT_TRUE(SIG_ERR != signal(SIGTERM, customSignalHandler));
-//}
-
-TEST(LogTest, FatalSIGTERM__UsingCustomHandler) {
-   RestoreFileLogger logger(log_directory);
-   g_fatal_counter.store(0);
-   g3::setFatalPreLoggingHook(fatalCounter);
-   installCustomSIGTERM();
-   g3::overrideSetupSignals({{SIGABRT, "SIGABRT"}, {SIGFPE, "SIGFPE"}, {SIGILL, "SIGILL"}});
-
-   installCustomSIGTERM();
-   EXPECT_EQ(customFatalCounter.load(), size_t{0});
-   EXPECT_EQ(lastEncounteredSignal.load(), 0);
-
-   raise(SIGTERM);
-   logger.reset();
-   EXPECT_EQ(g_fatal_counter.load(), size_t{0});
-   EXPECT_EQ(lastEncounteredSignal.load(), SIGTERM);
-   EXPECT_EQ(customFatalCounter.load(), size_t{1});
-}
-
-TEST(LogTest, FatalSIGTERM__VerifyingOldCustomHandler) {
-   RestoreFileLogger logger(log_directory);
-   g_fatal_counter.store(0);
-   customFatalCounter.store(0);
-   lastEncounteredSignal.store(0);
-
-   g3::setFatalPreLoggingHook(fatalCounter);
-   installCustomOldSIGTERM();
-   g3::overrideSetupSignals({{SIGABRT, "SIGABRT"}, {SIGFPE, "SIGFPE"}, {SIGILL, "SIGILL"}, {SIGTERM, "SIGTERM"}});
-   g3::restoreSignalHandler(SIGTERM);  // revert SIGTERM installation
-
-   EXPECT_EQ(customFatalCounter.load(), size_t{0});
-   EXPECT_EQ(lastEncounteredSignal.load(), 0);
-   EXPECT_FALSE(oldSigTermCheck.load());
-   raise(SIGTERM);
-   logger.reset();
-   EXPECT_EQ(g_fatal_counter.load(), size_t{0});
-   EXPECT_EQ(lastEncounteredSignal.load(), SIGTERM);
-   EXPECT_TRUE(oldSigTermCheck.load());
-}
-
-#endif
-
-#endif
-
-TEST(LogTest, LOG_preFatalLogging_hook) {
-   {
-      RestoreFileLogger logger(log_directory);
-      ASSERT_FALSE(mockFatalWasCalled());
-      g_fatal_counter.store(0);
-      g3::setFatalPreLoggingHook(fatalCounter);
-      LOG(FATAL) << "This message is fatal";
-      logger.reset();
-      EXPECT_EQ(g_fatal_counter.load(), size_t{1});
-   }
-   {
-      // Now with no fatal pre-logging-hook
-      RestoreFileLogger logger(log_directory);
-      ASSERT_FALSE(mockFatalWasCalled());
-      g_fatal_counter.store(0);
-      LOG(FATAL) << "This message is fatal";
-      EXPECT_EQ(g_fatal_counter.load(), size_t{0});
-   }
-}
-
-TEST(LogTest, LOG_FATAL) {
-   RestoreFileLogger logger(log_directory);
-   ASSERT_FALSE(mockFatalWasCalled());
-
-   LOG(FATAL) << "This message is fatal";
-   EXPECT_TRUE(mockFatalWasCalled());
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "This message is fatal"))
-      << "\ncontent: [[" << mockFatalMessage() << "]]";
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "FATAL"));
-
-   logger.reset();
-   std::string file_content = readFileToText(logger.logFile());
-   EXPECT_TRUE(verifyContent(file_content, "This message is fatal"));
-   EXPECT_TRUE(verifyContent(file_content, "FATAL"));
-   EXPECT_TRUE(verifyContent(file_content, "EXIT trigger caused by "));
-}
-TEST(LogTest, LOGF_IF__FATAL) {
-   RestoreFileLogger logger(log_directory);
-   EXPECT_FALSE(mockFatalWasCalled());
-   LOGF_IF(FATAL, (2 < 3), "This message %s be worse", "could");
-   EXPECT_TRUE(mockFatalWasCalled());
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by ")) << "\n"
-                                                                             << mockFatalMessage();
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "FATAL"));
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "This message could be worse"));
-
-   logger.reset();
-   std::string file_content = readFileToText(logger.logFile());
-   EXPECT_TRUE(verifyContent(file_content, "EXIT trigger caused by "));
-   EXPECT_TRUE(verifyContent(file_content, "FATAL"));
-   EXPECT_TRUE(verifyContent(file_content, "This message could be worse"));
-}
-TEST(LogTest, LOG_IF__FATAL) {
-   RestoreFileLogger logger(log_directory);
-   LOG_IF(WARNING, (0 != t_info.compare(t_info))) << "This message should NOT be written";
-   EXPECT_FALSE(mockFatalWasCalled());
-   LOG_IF(FATAL, (0 != t_info.compare(t_info2))) << "This message should throw. xyz ";
-   EXPECT_TRUE(mockFatalWasCalled());
-
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "FATAL"));
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "This message should throw. xyz "));
-
-   logger.reset();
-   std::string file_content = readFileToText(logger.logFile());
-   EXPECT_TRUE(verifyContent(file_content, "EXIT trigger caused by "));
-   EXPECT_TRUE(verifyContent(file_content, "FATAL"));
-   EXPECT_TRUE(verifyContent(file_content, "This message should throw. xyz "));
-}
-TEST(LogTest, LOG_IF__FATAL__NO_THROW) {
-   RestoreFileLogger logger(log_directory);
-   LOG_IF(FATAL, (2 > 3)) << "This message%sshould NOT throw";
-   ASSERT_FALSE(mockFatalWasCalled());
-}
-
-// CHECK_F
-TEST(CheckTest, CHECK_F__thisWILL_PrintErrorMsg) {
-   RestoreFileLogger logger(log_directory);
-   EXPECT_TRUE(mockFatalMessage().empty());
-   EXPECT_FALSE(mockFatalWasCalled());
-
-   CHECK(1 == 2);
-   EXPECT_FALSE(mockFatalMessage().empty());
-   EXPECT_TRUE(mockFatalWasCalled());
-
-   logger.reset();
-   std::string file_content = readFileToText(logger.logFile());
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
-   EXPECT_TRUE(verifyContent(file_content, "CONTRACT")) << "**** " << mockFatalMessage();
-}
-
-TEST(CHECK_F_Test, CHECK_F__thisWILL_PrintErrorMsg) {
-   RestoreFileLogger logger(log_directory);
-   std::string msg = "This message is added to throw %s and %s";
-   std::string arg1 = "message";
-   std::string arg3 = "log";
-
-   CHECK_F(1 >= 2, msg.c_str(), arg1.c_str(), arg3.c_str());
-   logger.reset();
-   std::string file_content = readFileToText(logger.logFile());
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
-   EXPECT_TRUE(verifyContent(file_content, "CONTRACT"));
-}
-
-TEST(CHECK_Test, CHECK__thisWILL_PrintErrorMsg) {
-   RestoreFileLogger logger(log_directory);
-   std::string msg = "This message is added to throw message and log";
-   CHECK(1 >= 2) << msg;
-
-   logger.reset();
-   std::string file_content = readFileToText(logger.logFile());
-   EXPECT_TRUE(verifyContent(mockFatalMessage(), "EXIT trigger caused by "));
-   EXPECT_TRUE(verifyContent(file_content, "CONTRACT"));
-   EXPECT_TRUE(verifyContent(file_content, msg));
-}
-TEST(CHECK, CHECK_ThatWontThrow) {
-   RestoreFileLogger logger(log_directory);
-   std::string msg = "This %s should never appear in the %s";
-   std::string msg3 = "This message should never appear in the log";
-   CHECK(1 == 1);
-   CHECK_F(1 == 1, msg.c_str(), "message", "log");
-   logger.reset();
-   EXPECT_FALSE(mockFatalWasCalled());
-
-   std::string file_content = readFileToText(logger.logFile());
-   EXPECT_FALSE(verifyContent(file_content, msg3));
-   EXPECT_FALSE(verifyContent(mockFatalMessage(), msg3));
-}
-
-TEST(CHECK, CHECK_runtimeError) {
-   RestoreFileLogger logger(log_directory);
-
-   g3::setFatalExitHandler([](g3::FatalMessagePtr msg) {
-      throw std::runtime_error("fatal test handler");
-   });
-
-   class dynamic_int_array {
-      std::unique_ptr<int[]> data_;
-      const int size_;
-
-     public:
-      explicit dynamic_int_array(int size) :
-          data_{std::make_unique<int[]>(size)},
-          size_(size) {}
-
-      int& at(int i) {
-         CHECK(i < size_);
-
-         // unreachable if i >= size_
-         return data_[i];
-      }
-   };
-
-   dynamic_int_array arr{3};
-
-   EXPECT_THROW(arr.at(3) = 1, std::runtime_error);
-}
 
 TEST(CustomLogLevels, AddANonFatal) {
    RestoreFileLogger logger(log_directory);
@@ -628,32 +346,6 @@ TEST(CustomLogLevels, AddANonFatal) {
                                                       << expected;
 }
 
-TEST(CustomLogLevels, AddFatal) {
-   RestoreFileLogger logger(log_directory);
-   const LEVELS DEADLY{FATAL.value + 1, {"DEADLY"}};
-   EXPECT_TRUE(g3::internal::wasFatal(DEADLY));
-   g_fatal_counter.store(0);
-   ASSERT_FALSE(mockFatalWasCalled());
-   g3::setFatalPreLoggingHook(fatalCounter);
-#ifdef G3_DYNAMIC_LOGGING
-   g3::only_change_at_initialization::addLogLevel(DEADLY, true);
-#endif
-   // clang-format off
-   LOG(DEADLY) << "Testing my own custom level"; auto line = __LINE__;
-   // clang-format on
-   logger.reset();
-   ASSERT_TRUE(mockFatalWasCalled());
-   EXPECT_EQ(size_t{1}, g_fatal_counter.load());
-
-   std::string file_content = readFileToText(logger.logFile());
-   std::string expected;
-   expected += "DEADLY [test_io.cpp->" + std::string(G3LOG_PRETTY_FUNCTION) + ":" + std::to_string(line);
-   EXPECT_TRUE(verifyContent(file_content, expected)) << file_content
-                                                      << "\n\nExpected: \n"
-                                                      << expected;
-   g_fatal_counter.store(0);  // restore
-}
-
 #ifdef G3_DYNAMIC_LOGGING
 namespace {
    // Restore dynamic levels if turned off

test_unit/test_signal.cpp

@@ -0,0 +1,62 @@
+#include <gtest/gtest.h>
+#include "g3log/crashhandler.hpp"
+
+#if !(defined(WIN32) || defined(_WIN32) || defined(__WIN32__))
+#include <fcntl.h>
+#include <unistd.h>
+
+class SignalHandlingTest : public ::testing::Test {
+  protected:
+   int original_stderr;
+   int pipefd[2];
+   FILE* temp_stderr;
+
+   void SetUp() override {
+      // Redirect stderr to a pipe
+      ASSERT_EQ(pipe(pipefd), 0);
+      original_stderr = dup(STDERR_FILENO);
+      ASSERT_NE(original_stderr, -1);
+      ASSERT_NE(dup2(pipefd[1], STDERR_FILENO), -1);
+      temp_stderr = fdopen(pipefd[1], "w");
+      setvbuf(temp_stderr, NULL, _IONBF, 0);  // Disable buffering
+
+      // Set the read end of the pipe to non-blocking mode
+      // so we can verify when buffer is empty
+      int flags = fcntl(pipefd[0], F_GETFL, 0);
+      fcntl(pipefd[0], F_SETFL, flags | O_NONBLOCK);
+   }
+
+   void TearDown() override {
+      // Restore the original stderr
+      fclose(temp_stderr);
+      close(pipefd[0]);
+      close(pipefd[1]);
+      dup2(original_stderr, STDERR_FILENO);
+      close(original_stderr);
+   }
+
+   std::string ReadStderr() {
+      char buffer[1024];
+      ssize_t bytes_read = read(pipefd[0], buffer, sizeof(buffer) - 1);
+      if (bytes_read >= 0) {
+         buffer[bytes_read] = '\0';  // Null-terminate the string
+         return std::string(buffer);
+      }
+      return "";
+   }
+};
+
+TEST_F(SignalHandlingTest, WriteErrorMessage_WritesToStderr) {
+   const char* test_message = "Test error message";
+   g3::internal::writeErrorMessage(test_message);
+   std::string output = ReadStderr();
+   ASSERT_EQ(output, test_message);
+}
+
+TEST_F(SignalHandlingTest, WriteErrorMessage_Nullptr_DoesNotWriteToStderr) {
+   g3::internal::writeErrorMessage(nullptr);
+   std::string output = ReadStderr();
+   ASSERT_TRUE(output.empty());
+}
+
+#endif  // #if !(defined(WIN32) || defined(_WIN32) || defined(__WIN32__))