How do I write unit tests and add test targets in CMake for C++?

Writing unit tests in C++ involves using a testing framework such as Google Test. To integrate unit tests with CMake, you can follow these steps:

1. Set Up Your Testing Framework

   Start by including the testing framework in your project. For Google Test, you may want to clone the repository or use a package manager to include it in your project.

2. Create Your Test Files

   Create a separate directory for your tests and create test source files there. For example, you can create a file named test_example.cpp.

3. Writing Your Tests

   Use the framework's syntax to write your tests. Here's a simple example using Google Test:

   #include 
   
   TEST(SampleTest, AssertionTrue) {
       EXPECT_TRUE(true);
   }
               

4. Add to Your CMakeLists.txt

   Add test targets in your CMakeLists.txt file to ensure that unit tests are compiled and can be run. Here’s an example:

   cmake_minimum_required(VERSION 3.10)
   
   # Project setup
   project(MyProject)
   
   # GoogleTest setup
   enable_testing()
   find_package(GTest REQUIRED)
   include_directories(${GTEST_INCLUDE_DIRS})
   
   # Add your main application
   add_executable(MyApp src/main.cpp)
   
   # Add your tests
   add_executable(MyTests test/test_example.cpp)
   target_link_libraries(MyTests GTest::GTest GTest::Main)
   
   # Register your tests
   add_test(NAME MyUnitTest COMMAND MyTests)
               

5. Build and Run Your Tests

   Finally, build your project using CMake and run your tests using the following commands:

   mkdir build
   cd build
   cmake ..
   make
   ctest