catch2/docs/configuration.md

Catch is designed to "just work" as much as possible. For most people the only configuration needed is telling Catch which source file should host all the implementation code (CATCH_CONFIG_MAIN).

Nonetheless there are still some occasions where finer control is needed. For these occasions Catch exposes a set of macros for configuring how it is built.

main()/ implementation

CATCH_CONFIG_MAIN	// Designates this as implementation file and defines main()
CATCH_CONFIG_RUNNER	// Designates this as implementation file

Although Catch is header only it still, internally, maintains a distinction between interface headers and headers that contain implementation. Only one source file in your test project should compile the implementation headers and this is controlled through the use of one of these macros - one of these identifiers should be defined before including Catch in exactly one implementation file in your project.

Prefixing Catch macros

CATCH_CONFIG_PREFIX_ALL

To keep test code clean and uncluttered Catch uses short macro names (e.g. TEST_CASE and REQUIRE). Occasionally these may conflict with identifiers from platform headers or the system under test. In this case the above identifier can be defined. This will cause all the Catch user macros to be prefixed with CATCH_ (e.g. CATCH_TEST_CASE and CATCH_REQUIRE).

Terminal colour

CATCH_CONFIG_COLOUR_NONE	// completely disables all text colouring
CATCH_CONFIG_COLOUR_WINDOWS	// forces the Win32 console API to be used
CATCH_CONFIG_COLOUR_ANSI	// forces ANSI colour codes to be used

Yes, I am English, so I will continue to spell "colour" with a 'u'.

When sending output to the terminal, if it detects that it can, Catch will use colourised text. On Windows the Win32 API, SetConsoleTextAttribute, is used. On POSIX systems ANSI colour escape codes are inserted into the stream.

For finer control you can define one of the above identifiers (these are mutually exclusive - but that is not checked so may behave unexpectedly if you mix them):

Note that when ANSI colour codes are used "unistd.h" must be includable - along with a definition of isatty()

Typically you should place the #define before #including "catch.hpp" in your main source file - but if you prefer you can define it for your whole project by whatever your IDE or build system provides for you to do so.

Console width

CATCH_CONFIG_CONSOLE_WIDTH = x // where x is a number

Catch formats output intended for the console to fit within a fixed number of characters. This is especially important as indentation is used extensively and uncontrolled line wraps break this. By default a console width of 80 is assumed but this can be controlled by defining the above identifier to be a different value.

stdout

CATCH_CONFIG_NOSTDOUT

Catch does not use std::cout and std::cerr directly but gets them from Catch::cout() and Catch::cerr() respectively. If the above identifier is defined these functions are left unimplemented and you must implement them yourself. Their signatures are:

std::ostream& cout();
std::ostream& cerr();

This can be useful on certain platforms that do not provide std::cout and std::cerr, such as certain embedded systems.

Other toggles

CATCH_CONFIG_COUNTER                    // Use __COUNTER__ to generate unique names for test cases
CATCH_CONFIG_WINDOWS_SEH                // Enable SEH handling on Windows
CATCH_CONFIG_FAST_COMPILE               // Sacrifices some (rather minor) features for compilation speed
CATCH_CONFIG_POSIX_SIGNALS              // Enable handling POSIX signals
CATCH_CONFIG_WINDOWS_CRTDBG             // Enable leak checking using Windows's CRT Debug Heap

Currently Catch enables CATCH_CONFIG_WINDOWS_SEH only when compiled with MSVC, because some versions of MinGW do not have the necessary Win32 API support.

CATCH_CONFIG_POSIX_SIGNALS is on by default, except when Catch is compiled under Cygwin, where it is disabled by default (but can be force-enabled by defining CATCH_CONFIG_POSIX_SIGNALS).

CATCH_CONFIG_WINDOWS_CRTDBG is off by default. If enabled, Windows's CRT is used to check for memory leaks, and displays them after the tests finish running.

These toggles can be disabled by using _NO_ form of the toggle, e.g. CATCH_CONFIG_NO_WINDOWS_SEH.

CATCH_CONFIG_FAST_COMPILE

Defining this flag speeds up compilation of test files by ~20%, by making 2 changes:

• The -b (--break) flag no longer makes Catch break into debugger in the same stack frame as the failed test, but rather in a stack frame below.
• The REQUIRE family of macros (REQUIRE, REQUIRE_FALSE and REQUIRE_THAT) no longer uses local try-catch block. This disables exception translation, but should not lead to false negatives.

CATCH_CONFIG_FAST_COMPILE has to be either defined, or not defined, in all translation units that are linked into single test binary, or the behaviour of setting -b flag and throwing unexpected exceptions will be unpredictable.

Windows header clutter

On Windows Catch includes windows.h. To minimize global namespace clutter in the implementation file, it defines NOMINMAX and WIN32_LEAN_AND_MEAN before including it. You can control this behaviour via two macros:

CATCH_CONFIG_NO_NOMINMAX            // Stops Catch from using NOMINMAX macro 
CATCH_CONFIG_NO_WIN32_LEAN_AND_MEAN // Stops Catch from using WIN32_LEAN_AND_MEAN macro

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