Testing with CI
When a Pull Request is opened on GitHub, GitHub Actions will automatically
launch a build that will run all tests on some configurations
(x86_64-gnu-llvm-13 linux, x86_64-gnu-tools linux, and mingw-check linux).
In essence, each runs
./x.py test with various different options.
The integration bot bors is used for coordinating merges to the master branch. When a PR is approved, it goes into a queue where merges are tested one at a time on a wide set of platforms using GitHub Actions. Due to the limit on the number of parallel jobs, we run CI under the rust-lang-ci organization except for PRs. Most platforms only run the build steps, some run a restricted set of tests, only a subset run the full suite of tests (see Rust's platform tiers).
If everything passes, then all of the distribution artifacts that were generated during the CI run are published.
Using CI to test
In some cases, a PR may run into problems with running tests on a particular platform or configuration. If you can't run those tests locally, don't hesitate to use CI resources to try out a fix.
As mentioned above, opening or updating a PR will only run on a small subset of configurations. Only when a PR is approved will it go through the full set of test configurations. However, you can try one of those configurations in your PR before it is approved. For example, if a Windows build fails, but you don't have access to a Windows machine, you can try running the Windows job that failed on CI within your PR after pushing a possible fix.
To do this, you'll need to edit
jobs section defines the jobs that will run.
jobs.pr section defines everything that will run in a push to a PR.
jobs.auto section defines the full set of tests that are run after a PR is approved.
You can copy one of the definitions from the
auto section up to the
For example, the
x86_64-msvc-2 jobs are responsible for
running the 64-bit MSVC tests.
You can copy those up to the
jobs.pr.strategy.matrix.include section with
the other jobs.
The comment at the top of
ci.yml will tell you to run this command:
./x.py run src/tools/expand-yaml-anchors
This will generate the true
.github/workflows/ci.yml which is what GitHub
Then, you can commit those two files and push to GitHub. GitHub Actions should launch the tests.
After you have finished, don't forget to remove any changes you have made to
Although you are welcome to use CI, just be conscientious that this is a shared resource with limited concurrency. Try not to enable too many jobs at once (one or two should be sufficient in most cases).