Catch2

Catch2 was created by Phil Nash as the successor to the original Catch framework. Its goal is to simplify unit testing in C++ by providing expressive macros, automatic test registration, and rich reporting while being lightweight and easy to integrate.

Catch2 is a modern, header-only C++ unit testing framework. It provides a simple syntax for writing test cases and assertions, making it easy to write, maintain, and execute tests for C++ projects.

Installation

Usage

Catch2 allows defining test cases with `TEST_CASE` macros and verifying conditions using `REQUIRE`, `CHECK`, and related assertions. It supports sections, tags, BDD-style tests, and integration with build systems for automated testing.

#define CATCH_CONFIG_MAIN
#include <catch2/catch.hpp>

TEST_CASE("Factorials are computed correctly", "[factorial]") {
    REQUIRE( Factorial(0) == 1 );
    REQUIRE( Factorial(1) == 1 );
    REQUIRE( Factorial(2) == 2 );
    REQUIRE( Factorial(3) == 6 );
}

TEST_CASE("Vectors can be sized and resized", "[vector]") {
    std::vector<int> v(5);
    CHECK( v.size() == 5 );
    v.push_back(1);
    CHECK( v.size() == 6 );
}

TEST_CASE("Testing different scenarios") {
    SECTION("Empty vector") {
        std::vector<int> v;
        REQUIRE(v.empty());
    }
    SECTION("Non-empty vector") {
        std::vector<int> v = {1,2,3};
        REQUIRE(v.size() == 3);
    }
}

TEST_CASE("String manipulation", "[string][manipulation]") {
    REQUIRE( toUpper("abc") == "ABC" );
}

SCENARIO("Vectors can be resized") {
    GIVEN("A vector with 3 elements") {
        std::vector<int> v = {1,2,3};
        WHEN("an element is added") {
            v.push_back(4);
            THEN("the size increases") {
                REQUIRE(v.size() == 4);
            }
        }
    }
}

Error Handling

Best Practices

Use `REQUIRE` for critical assertions and `CHECK` for non-fatal checks.

Organize tests with tags for selective execution.

Use sections to reduce code duplication for similar test scenarios.

Keep test cases small and focused on a single functionality.

Integrate Catch2 tests with CI pipelines for automated testing.