NanoTest

A minimal C++20/CMake testing library. One header, one assertion, automatic CTest integration.

Macro-free by design.

Quick Start

tests.cpp:

#include <NanoTest/NanoTest.h>

using namespace nano;

auto addition = test("Addition") = []
{
    check(2 + 2 == 4);
};

Using using namespace nano; keeps test files expressive and free of repetitive prefixes.

CMake Integration

CMakeLists.txt:

cmake_minimum_required(VERSION 3.21)
project(NanoTestExample)

set(CMAKE_CXX_STANDARD 20)

include(FetchContent)

FetchContent_Declare(
        NanoTest
        GIT_REPOSITORY https://github.com/eyalamirmusic/NanoTest.git
        GIT_TAG v1.0.0
)

FetchContent_MakeAvailable(NanoTest)

enable_testing()
nano_add_executable(MyTests SOURCES tests.cpp)

nano_add_executable creates a test executable with a generated main(), links NanoTest, and registers each test case individually with CTest. You can also link your own libraries using TARGETS:

nano_add_executable(MyTests SOURCES tests.cpp TARGETS MyLib)

Custom main()

By default, nano_add_executable provides a main() that calls nano::run. If you need custom setup before running tests, pass NO_MAIN and write your own:

nano_add_executable(MyTests SOURCES tests.cpp NO_MAIN)

int main(int argc, char* argv[])
{
    // custom setup ...
    return nano::run(argc, argv);
}

Setting up an existing target

Use nano_setup_target to set up a target you've already created with add_executable. This links NanoTest (without a generated main()) and discovers tests:

add_executable(MyTests tests.cpp)
nano_setup_target(MyTests TARGETS MyLib)

Pass WITH_MAIN if you want the generated main():

add_executable(MyTests tests.cpp)
nano_setup_target(MyTests WITH_MAIN)

Both functions also accept TEST_PREFIX to namespace CTest entries when test names might collide across targets:

nano_add_executable(MyTests SOURCES tests.cpp TEST_PREFIX "MyTests:")

Build and run:

cmake -B build && cmake --build build && ctest --test-dir build

1/1 Test #1: Addition .....   Passed    0.00 sec

Each test is automatically discovered and registered with CTest.

Running Tests

# Run all tests
ctest --test-dir build --output-on-failure

# Run a single test by name
./build/MyTests --test Addition

# List all registered tests
./build/MyTests --list-tests

Cross-Compilation

NanoTest builds on iOS, Emscripten, and other cross-compilation targets. Test discovery is automatically skipped when cross-compiling, falling back to a single CTest entry per executable.

API Reference

Function	Description
nano::test(name) = body	Register a test case
nano::check(expr)	Assert that an expression is true
nano::run(argc, argv)	Run tests, supports --list-tests and --test <name>

Requirements

• C++20
• CMake 3.21+

License

MIT