modern-cmake/chapters/testing/catch.md

Catch

Catch2 (C++11 only version) is a powerful, idomatic testing solutions similar in philosophy to PyTest for Python. It supports a wider range of compilers than GTest, and is quick to support new things, like M1 builds on macOS. It also has a smaller but faster twin, doctest, which is quick to compile but misses features like matchers. To use Catch in a CMake project, there are several options.

Configure methods

Catch has nice CMake support, though to use it, you need the full repo. This could be with submodules or FetchContent. Both the extended-project and fetch examples use FetchContent. See the docs.

Quick download

This is likely the simplest method and supports older versions of CMake. You can download the all-in-one header file in one step:

add_library(catch_main main.cpp)
target_include_directories(catch_main PUBLIC "${CMAKE_CURRENT_SOURCE_DIR}")
set(url https://github.com/philsquared/Catch/releases/download/v2.13.6/catch.hpp)
file(
  DOWNLOAD ${url} "${CMAKE_CURRENT_BINARY_DIR}/catch.hpp"
  STATUS status
  EXPECTED_HASH SHA256=681e7505a50887c9085539e5135794fc8f66d8e5de28eadf13a30978627b0f47)
list(GET status 0 error)
if(error)
  message(FATAL_ERROR "Could not download ${url}")
endif()
target_include_directories(catch_main PUBLIC "${CMAKE_CURRENT_BINARY_DIR}")

This will two downloads when Catch 3 is released, as that now requires two files (but you no longer have to write a main.cpp). The main.cpp looks like this:

#define CATCH_CONFIG_MAIN
#include "catch.hpp"

Vendoring

If you simply drop in the single include release of Catch into your project, this is what you would need to add Catch:

# Prepare "Catch" library for other executables
set(CATCH_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/extern/catch)
add_library(Catch2::Catch IMPORTED INTERFACE)
set_property(Catch2::Catch PROPERTY INTERFACE_INCLUDE_DIRECTORIES "${CATCH_INCLUDE_DIR}")

Then, you would link to Catch2::Catch. This would have been okay as an INTERFACE target since you won't be exporting your tests.

Direct inclusion

If you add the library using ExternalProject, FetchContent, or git submodules, you can also add_subdirectory Catch (CMake 3.1+).

Catch also provides two CMake modules that you can use to register the individual tests with CMake.