cppUnitTest

A lightweight, single-header unit testing framework for C++. No dependencies, no installation — just drop test.h into your project and start writing tests.

Installation

Copy test.h into your project. That's it.

#include "test.h"

Quick Start

#include "test.h"

int sum(int a, int b) { return a + b; }

void test_negative_inputs(test_result& r) {
    if (sum(1, -2) == -1) {
        r.passed = true;
    } else {
        r.log = "Expected: -1, Got: " + std::to_string(sum(1, -2));
        r.passed = false;
    }
}

int main() {
    Test suite("Sum function tests");
    suite.add_test("Negative inputs", test_negative_inputs);
    suite.add_test("Intentional fail", [](test_result& r) {
        r.log = "Not implemented yet";
        r.passed = false;
    });
    suite.run();
    return 0;
}

Output:

Running: Sum function tests
    #### Test 1 : 2 PASS
    #### Test 2 : 2 FAILED
        Not implemented yet on Test: Intentional fail
Passed 1 out of 2

Pass/fail results are color-coded green and red in the terminal.

Test Functions

All test functions share the same signature — void return, single test_result& parameter. They can be either named functions or lambdas:

// Named function
void my_test(test_result& r) {
    r.passed = true;
}

// Lambda
auto my_lambda = [](test_result& r) -> void {
    r.passed = false;
    r.log = "Failed because...";
};

The test_result struct has three fields you care about:

Field	Type	Purpose
passed	bool	Whether the test passed
log	std::string	Message printed on failure
description	std::string	Set automatically from add_test()

Repeating Tests

For randomized or stress tests, register a test with a repeat count. The suite runs it N times and reports how many passed:

suite.add_test("Random input stress test", [](test_result& r) {
    int x = rand() % 100;
    r.passed = (x >= 0); // trivially true, but you get the idea
}, 100); // run 100 times

Output reports Passed N out of 100 for the batch.

Saving Results to a File

Pass a filename to run() to write results to disk instead of stdout:

suite.run("results.txt");

API Reference

// Create a named test suite
Test suite("My Suite");

// Add a single test
suite.add_test("test name", test_function);

// Add a repeating test (runs N times, reports pass rate)
suite.add_test("test name", test_function, N);

// Run and print to stdout (color-coded)
suite.run();

// Run and write to file
suite.run("output.txt");

License

MIT