mirror of
https://github.com/catchorg/Catch2.git
synced 2024-11-20 12:26:10 +01:00
85 lines
3.8 KiB
Markdown
85 lines
3.8 KiB
Markdown
<a id="top"></a>
|
|
# Migrating from v2 to v3
|
|
|
|
v3 is the next major version of Catch2 and brings three significant changes:
|
|
* Catch2 is now split into multiple headers
|
|
* Catch2 is now compiled as a static library
|
|
* C++14 is the minimum required C++ version
|
|
|
|
There are many reasons why we decided to go from the old single-header
|
|
distribution model to a more standard library distribution model. The
|
|
big one is compile-time performance, but moving over to a split header
|
|
distribution model also improves the future maintainability and
|
|
extendability of the codebase. For example v3 adds a new kind of matchers
|
|
without impacting the compilation times of users that do not use matchers
|
|
in their tests. The new model is also more friendly towards package
|
|
managers, such as vcpkg and Conan.
|
|
|
|
The result of this move is a significant improvement in compilation
|
|
times, e.g. the inclusion overhead of Catch2 in the common case has been
|
|
reduced by roughly 80%. The improved ease of maintenance also led to
|
|
various runtime performance improvements and the introduction of new features.
|
|
For details, look at [the release notes of 3.0.1](release-notes.md#301).
|
|
|
|
_Note that we still provide one header + one TU distribution but do
|
|
not consider it the primarily supported option. You should also expect
|
|
that the compilation times will be worse if you use this option._
|
|
|
|
|
|
## How to migrate projects from v2 to v3
|
|
|
|
To migrate to v3, there are two basic approaches to do so.
|
|
|
|
1. Use `catch_amalgamated.hpp` and `catch_amalgamated.cpp`.
|
|
2. Build Catch2 as a proper (static) library, and move to piecewise headers
|
|
|
|
Doing 1 means downloading the [amalgamated header](/extras/catch_amalgamated.hpp)
|
|
and the [amalgamated sources](/extras/catch_amalgamated.cpp) from `extras`,
|
|
dropping them into your test project, and rewriting your includes from
|
|
`<catch2/catch.hpp>` to `"catch_amalgamated.hpp"` (or something similar,
|
|
based on how you set up your paths).
|
|
|
|
The disadvantage of using this approach are increased compilation times,
|
|
at least compared to the second approach, but it does let you avoid
|
|
dealing with consuming libraries in your build system of choice.
|
|
|
|
|
|
However, we recommend doing 2, and taking extra time to migrate to v3
|
|
properly. This lets you reap the benefits of significantly improved
|
|
compilation times in the v3 version. The basic steps to do so are:
|
|
|
|
1. Change your CMakeLists.txt to link against `Catch2WithMain` target if
|
|
you use Catch2's default main. (If you do not, keep linking against
|
|
the `Catch2` target.)
|
|
2. Delete TU with `CATCH_CONFIG_RUNNER` or `CATCH_CONFIG_MAIN` defined,
|
|
as it is no longer needed.
|
|
3. Change `#include <catch2/catch.hpp>` to `#include <catch2/catch_all.hpp>`
|
|
4. Check that everything compiles. You might have to modify namespaces,
|
|
or perform some other changes (see the
|
|
[Things that can break during porting](#things-that-can-break-during-porting)
|
|
section for the most common things).
|
|
5. Start migrating your test TUs from including `<catch2/catch_all.hpp>`
|
|
to piecemeal includes. You will likely want to start by including
|
|
`<catch2/catch_test_macros.hpp>`, and then go from there. (see
|
|
[other notes](#other-notes) for further ideas)
|
|
|
|
## Other notes
|
|
* The main test include is now `<catch2/catch_test_macros.hpp>`
|
|
* Big "subparts" like Matchers, or Generators, have their own folder, and
|
|
also their own "big header", so if you just want to include all matchers,
|
|
you can include `<catch2/matchers/catch_matchers_all.hpp>`,
|
|
or `<catch2/generators/catch_generators_all.hpp>`
|
|
|
|
|
|
## Things that can break during porting
|
|
* The namespace on Matchers were cleaned up, they are no longer first declared
|
|
deep within an internal namespace and then brought up. All Matchers now live
|
|
in `Catch::Matchers`.
|
|
* The reporter interfaces changed in a breaking manner. If you wrote custom
|
|
reporter or listener, you might need to modify them a bit.
|
|
|
|
|
|
---
|
|
|
|
[Home](Readme.md#top)
|