feat: harden logger lifecycle and add tests

CMakeLists.txt

@@ -1,7 +1,34 @@
-project(MyLogger)
+cmake_minimum_required(VERSION 3.16)
 
-add_library(${PROJECT_NAME} ${PROJECT_SOURCE_DIR}/loghandler.cpp)
+project(MyLogger LANGUAGES CXX)
 
-target_link_libraries(${PROJECT_NAME}
-        Qt5::Core
-        )
+# 同时识别 Qt5 与 Qt6，避免公共模块把消费者固定在单一 Qt 主版本。
+find_package(QT NAMES Qt6 Qt5 REQUIRED COMPONENTS Core)
+find_package(Qt${QT_VERSION_MAJOR} REQUIRED COMPONENTS Core)
+
+add_library(MyLogger SHARED
+    loghandler.cpp
+    loghandler.h
+)
+
+# 目标自身导出符号，使用方只获得公共头文件、C++17 要求和 Qt Core 传递依赖。
+target_compile_features(MyLogger PUBLIC cxx_std_17)
+target_compile_definitions(MyLogger PRIVATE MYLOGGER_LIBRARY QT_MESSAGELOGCONTEXT)
+target_include_directories(MyLogger PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>)
+target_link_libraries(MyLogger PUBLIC Qt${QT_VERSION_MAJOR}::Core)
+
+# 测试目标直接编译日志源码并开启测试访问宏，避免依赖已安装 DLL，也不改变正式库的公开行为。
+include(CTest)
+if(BUILD_TESTING)
+    find_package(Qt${QT_VERSION_MAJOR} REQUIRED COMPONENTS Test)
+    add_executable(MyLoggerTests
+        tests/tst_loghandler.cpp
+        loghandler.cpp
+        loghandler.h
+    )
+    target_compile_features(MyLoggerTests PRIVATE cxx_std_17)
+    target_compile_definitions(MyLoggerTests PRIVATE MYLOGGER_STATIC MYLOGGER_TESTING QT_MESSAGELOGCONTEXT)
+    target_include_directories(MyLoggerTests PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
+    target_link_libraries(MyLoggerTests PRIVATE Qt${QT_VERSION_MAJOR}::Core Qt${QT_VERSION_MAJOR}::Test)
+    add_test(NAME MyLoggerTests COMMAND MyLoggerTests)
+endif()