The fastest feature-rich C++11 single-header testing framework for unit tests and TDD
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doctest is a new C++ testing framework but is by far the fastest both in compile times (by orders of magnitude) and runtime compared to other feature-rich alternatives. It brings the ability of compiled languages such as D / Rust / Nim to have tests written directly in the production code by providing a fast, transparent and flexible test runner with a clean interface.

The framework is and will stay free but needs your support to sustain its development. There are lots of new features and maintenance to do. If you work for a company using doctest or have the means to do so, please consider financial support. Monthly donations via Patreon and one-offs via PayPal.

A complete example with a self-registering test that compiles to an executable looks like this:


There are many C++ testing frameworks - Catch, Boost.Test, UnitTest++, cpputest, googletest and many other.

The key differences between it and other testing frameworks are that it is light and unintrusive:

  • Ultra light on compile times both in terms of including the header and writing thousands of asserts
  • Doesn't produce any warnings even on the most aggressive warning levels for MSVC/GCC/Clang
  • Offers a way to remove everything testing-related from the binary with the DOCTEST_CONFIG_DISABLE identifier
  • thread-safe - asserts (and logging) can be used from multiple threads spawned from a single test case - example
  • asserts can be used outside of a testing context - as a general purpose assert library - example
  • Doesn't pollute the global namespace (everything is in namespace doctest) and doesn't drag any headers with it
  • Very portable C++11 (use tag 1.2.9 for C++98) with over 180 different CI builds (static analysis, sanitizers...)


This allows the framework to be used in more ways than any other - tests can be written directly in the production code!

Mantra: Tests can be considered a form of documentation and should be able to reside near the production code which they test.

  • This makes the barrier for writing tests much lower - you don't have to: 1) make a separate source file 2) include a bunch of stuff in it 3) add it to the build system and 4) add it to source control - You can just write the tests for a class or a piece of functionality at the bottom of its source file - or even header file!
  • Tests in the production code can be thought of as documentation or up-to-date comments - showing how an API is used
  • Testing internals that are not exposed through the public API and headers is no longer a mind-bending exercise
  • Test-driven development in C++ has never been easier!

The framework can be used like any other if you don't want/need to mix production code and tests - check out the features.

doctest is modeled after Catch and some parts of the code have been taken directly - check out the differences.

This table compares doctest / Catch / lest which are all very similar.

Standard License Version download CII Best Practices Join the chat at Try it online

Checkout the CppCon 2017 talk on YouTube to get a better understanding of how the framework works and read about how to use it in the article of the february edition of ACCU Overload 2017!

CppCon 2017 talk about doctest on youtube





Support the development of the project with donations! There is a list of planned features which are all important and big - see the roadmap. I took a break from working in the industry to make open source software so every cent is a big deal.

If you work for a company using doctest or have the means to do so, please consider financial support.

Contributions in the form of issues and pull requests are welcome as well - check out the Contributing page.


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