ut VS doctest

I don't think stepping through static_assert is a thing? Curious if it is, though. Since constexpr is either run-time or compile-time and static_assert is not a poor man's debugging facility could be to -Dstatic_assert(...) assert(__VA_ARGS__) and gdb the code. Alternatively, a more refined solution would be to use an UT framework (for example https://github.com/boost-ext/ut) which helps with that. IMHO, TDD can also limit the requirement of stepping into the code and with gurantees that the code is memory safe and UB safe there is less need for sanitizers and valgrind etc. depending on the coverage.

It was not easy, I had to modify Boost UT to get it to run my tests. It doesn't support type-parametrized tests when the type parameter is non-copiable, which was the case for me. This is a symptom of a larger issue, which is that it relies on std::apply and std::tuple to generate the type-parametrized tests, which in turns requires instantiating the tuple and the contained objects (even though these instances aren't actually used; eh). That's a no go for me, since I need to carefully monitor when instance are created, and this was throwing off my test code. I had to effectively disable these checks to get it to run without failures. Then there was a similar issue with expect(), which doesn't work if part of the expression is non-copiable. I reported these issues to them.

https://github.com/boost-ext/ut (for better user interface when defining tests without macros)

https://github.com/boost-ext/ut from Kris Jusiak is worth checking

C++: C++ has quite a number of benchmarking libraries some of the recent ones involving C++ 20's flexibility. The most notable being Google Bench and UT. C does not have many specific benchmarking libraries, but you can easily integrate C code with C++ benchmarking libraries in order to test the performance of your C code.

UT

In Boost.UT there is a number of different styles to add a parametrized test case. All of them are pretty cryptic bue to heavy isage of oeverloaded operators of custom "non-public" classes. Except for the for-loop method, in all other methods the list of parameter values goes after the test procedure definition. I find this inconvenient, as I want to see list of parameter value next to the test name. This is what I used to from the times I was coding a lot of unit tests in C#.

I have never used "tools" for unit-tests, only web sites that show the results of the tests or code coverage. For C++ I prefer https://github.com/doctest/doctest but most companies I worked for use Catch2.

Do the README and tutorial not explain it well enough? It's a framework for automated unit testing.

This is, honestly, super easy to get going. Nowadays you have a ton of libraries and more-than-decent build systems. With Meson/CMake and Conan/Vcpkg I can set up a project with testing in 3 minutes. Also, I think that at the end of the day you want your tests to live somewhere else. But if you want to embed them, you also have https://github.com/doctest/doctest.

Write some tests. They can find bugs early and give you confidence that your code works so far. That doesn't have to be anything fancy, e.g. with doctest:

Keep in mind https://github.com/doctest/doctest/issues/554. Also, doctest lacks: - Matchers - Data generators - Benchmarking - ...

Your requirements can easily simulated on paper (like increase the speed once, twice, ...), then translated to unit-tests with a framework like https://github.com/doctest/doctest.

I like working in C++, after a decade of working in Java, Python, Javascript and Clojure, I find working in C++ (which I learned before these other languages) to be quite fun and pleasant, at least with relatively modern C++.

I've been, on and off, working on a little toy game engine, for a few years. Its a mix of keeping up with C++ advancements, learning various concepts like physically based rendering, and just the fun of crafting a big project, with no constraints other than my time and ability, no deadlines, no expectation of releasing anything. Its cathartic and enjoyable. I really do enjoy it.

Last September, I got frustrated with something I was working on in a more serious capacity. It was some server software, it responded to HTTP requests, it accessed third party services over HTTP and Websockets, it talked to a Postgres database. Overall it was an event driven system that transformed data and generated actions that would be applied by talking to third party services. The "real" version was written in Clojure and it worked pretty well. I really like Clojure, so all good.

But because I was frustrated with some things about how it ran and the resources it took up, I wondered what it would be like if I developed a little lean-and-mean version in C++. So I gave it a try as a side project for a few weeks. I used doctest[1] for testing, immer[2] for Clojure-like immutable data structures, [3] lager for Elm-like application state and logic management, Crow[4] for my HTTP server, ASIO[5] and websocketpp[6] for Websockets, cpp-httplib[7] as a HTTP client and PGFE[8] for Postgres, amongst some other little utility libraries. I also wrote it in a Literate Programming style using Entangled[9], which helped me keep everything well documented and explained.

For the most part, it worked pretty well. Using immer and lager helped keep the logic safe and to the point. The application started and ran very quickly and used very little cpu or memory. However, as the complexity grew, especially when using template heavy libraries like lager, or dealing with complex things like ASIO, it became very frustrating to deal with errors. Template errors even on clang became incomprehensible and segmentation faults when something wasn't quite right became pretty hard to diagnose. I had neither of these problems working on my game engine, but both became issues on this experiment. After a few weeks, I gave up on it. I do think I could have made it work and definitely could go back and simplify some of the decisions I made to make it more manageable, but ultimately, it was more work than I had free time to dedicate to it.

So my experience was that, yes, you can write high level application logic for HTTP web backends in C++. You can even use tools like immer or lager to make it feel very functional-programming in style and make the application logic really clean. Its not hard to make it run efficiently both in terms of running time and memory usage, certainly when comparing to Clojure or Python. However, I found that over all, it just wasn't as easy or productive as either of those languages and I spent more time fighting the language deficiencies, even with modern C++, than I do when using Clojure or Python.

I think I would think very long and hard before seriously considering writing a web backend in C++. If I had the time, I'd love to retry the experiment but using Rust, to see how it compares.

[1] https://github.com/doctest/doctest

[2] https://github.com/arximboldi/immer

[3] https://github.com/arximboldi/lager

[4] https://github.com/CrowCpp/crow

[5] https://think-async.com/Asio/

[6] https://www.zaphoyd.com/projects/websocketpp/

[7] https://github.com/yhirose/cpp-httplib

[8] https://github.com/dmitigr/pgfe

[9] https://entangled.github.io/

For stuff like this which is very easy to test (very predefined input vs output), I highly suggest using some testing framework. Catch2 is great, but there is also doctest and good ole googletest. If you do this, it would also be a great intro to CI, where you do some plumbing on github or gitlab where every commit causes a build to happen on their servers and run through the unit tests, and if it passes it gets merged into master.

doctest is my favorite framework. Really simple to use, header only, supports compile-time tests, lots of features and it works well with cmake.