catch2/docs/other-macros.md

Other macros

This page serves as a reference for macros that are not documented elsewhere. For now, these macros are separated into 2 rough categories, "assertion related macros" and "test case related macros".

Assertion related macros

• CHECKED_IF and CHECKED_ELSE

CHECKED_IF( expr ) is an if replacement, that also applies Catch2's stringification machinery to the expr and records the result. As with if, the block after a CHECKED_IF is entered only if the expression evaluates to true. CHECKED_ELSE( expr ) work similarly, but the block is entered only if the expr evaluated to false.

Example:

int a = ...;
int b = ...;
CHECKED_IF( a == b ) {
    // This block is entered when a == b
} CHECKED_ELSE ( a == b ) {
    // This block is entered when a != b
}

• CHECK_NOFAIL

CHECK_NOFAIL( expr ) is a variant of CHECK that does not fail the test case if expr evaluates to false. This can be useful for checking some assumption, that might be violated without the test necessarily failing.

Example output:

main.cpp:6:
FAILED - but was ok:
  CHECK_NOFAIL( 1 == 2 )

main.cpp:7:
PASSED:
  CHECK( 2 == 2 )

• SUCCEED

SUCCEED( msg ) is mostly equivalent with INFO( msg ); REQUIRE( true );. In other words, SUCCEED is for cases where just reaching a certain line means that the test has been a success.

Example usage:

TEST_CASE( "SUCCEED showcase" ) {
    int I = 1;
    SUCCEED( "I is " << I );
}

• STATIC_REQUIRE

STATIC_REQUIRE( expr ) is a macro that can be used the same way as a static_assert, but also registers the success with Catch2, so it is reported as a success at runtime. The whole check can also be deferred to the runtime, by defining CATCH_CONFIG_RUNTIME_STATIC_REQUIRE before including the Catch2 header.

Example:

TEST_CASE("STATIC_REQUIRE showcase", "[traits]") {
    STATIC_REQUIRE( std::is_void<void>::value );
    STATIC_REQUIRE_FALSE( std::is_void<int>::value );
}

Test case related macros

• METHOD_AS_TEST_CASE

METHOD_AS_TEST_CASE( member-function-pointer, description ) lets you register a member function of a class as a Catch2 test case. The class will be separately instantiated for each method registered in this way.

class TestClass {
    std::string s;

public:
    TestClass()
        :s( "hello" )
    {}

    void testCase() {
        REQUIRE( s == "hello" );
    }
};


METHOD_AS_TEST_CASE( TestClass::testCase, "Use class's method as a test case", "[class]" )

• REGISTER_TEST_CASE

REGISTER_TEST_CASE( function, description ) let's you register a function as a test case. The function has to have void() signature, the description can contain both name and tags.

Example:

REGISTER_TEST_CASE( someFunction, "ManuallyRegistered", "[tags]" );

Note that the registration still has to happen before Catch2's session is initiated. This means that it either needs to be done in a global constructor, or before Catch2's session is created in user's own main.

• ANON_TEST_CASE

ANON_TEST_CASE is a TEST_CASE replacement that will autogenerate unique name. The advantage of this is that you do not have to think of a name for the test case,`the disadvantage is that the name doesn't necessarily remain stable across different links, and thus it might be hard to run directly.

Example:

ANON_TEST_CASE() {
    SUCCEED("Hello from anonymous test case");
}

• DYNAMIC_SECTION

DYNAMIC_SECTION is a SECTION where the user can use operator<< to create the final name for that section. This can be useful with e.g. generators, or when creating a SECTION dynamically, within a loop.

Example:

TEST_CASE( "looped SECTION tests" ) {
    int a = 1;

    for( int b = 0; b < 10; ++b ) {
        DYNAMIC_SECTION( "b is currently: " << b ) {
            CHECK( b > a );
        }
    }
}