CMake and testing

In plain English

CMake is a build tool that describes what to build and how, independent of any single compiler or IDE. A target is a named thing CMake can build, such as an executable or a library, and you attach sources, options and dependencies to it. A test framework such as Catch2 or GoogleTest lets you write assertions that check behaviour and report failures automatically. CMake can discover and register those tests so a single command runs them all. Writing tests before or alongside code turns a vague feature into a list of facts the program must satisfy.

Step by step

1. 1Write a CMakeLists.txt with cmake_minimum_required and project.
2. 2Set the C++ standard to 20 and require it.
3. 3Create a test executable target and link the Catch2 or GoogleTest library.
4. 4Register the test with CTest using add_test.
5. 5Configure, build, then run ctest to see the results.

cmake_minimum_required(VERSION 3.20)
project(edubyte_test CXX)

set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(Catch2 3 REQUIRED)

add_executable(lesson_tests test/lesson_test.cpp)
target_link_libraries(lesson_tests PRIVATE Catch2::Catch2WithMain)

include(CTest)
add_test(NAME lesson_tests COMMAND lesson_tests)

Common mistakes

• Forgetting to link the test framework library leaves undefined references at link time.
• Registering a test without include(CTest) or enable_testing() means ctest will not find it.
• Hardcoding absolute paths in CMake breaks the build for anyone else who clones the project.
• Skipping assertions for edge cases means the tests pass while the feature still fails in real use.