Expand the testing section of the hacking docs

- Make it clear what the different kind of tests are, where they live
  and how they can be ran
- Ask people to primarily write unit tests
This commit is contained in:
Théophane Hufschmitt 2022-05-10 11:56:47 +02:00
parent 3ec979fa90
commit 7c75f1d52b

View file

@ -71,18 +71,6 @@ To install it in `$(pwd)/outputs` and test it:
nix (Nix) 3.0
```
To run a functional test:
```console
make tests/test-name-should-auto-complete.sh.test
```
To run the unit-tests for C++ code:
```
make check
```
If you have a flakes-enabled Nix you can replace:
```console
@ -94,3 +82,32 @@ by:
```console
$ nix develop
```
## Testing
Nix comes with three different flavors of tests: unit, functional and integration.
Most tests are currently written as functional tests.
**However**, it is preferable (as much as it makes sense) to primarily test new code with unit tests.
### Unit-tests
The unit-tests for each Nix library (`libexpr`, `libstore`, etc..) are defined
under `src/{library_name}/tests` using the
[googletest](https://google.github.io/googletest/) framework.
You can run the whole testsuite with `make check`, or the tests for a specific component with `make libfoo-tests_RUN`. Finer-grained filtering is also possible using the [--gtest_filter](https://google.github.io/googletest/advanced.html#running-a-subset-of-the-tests) command-line option.
### Functional tests
The functional tests reside under the `tests` directory and are listed in `tests/local.mk`.
The whole testsuite can be run with `make install && make installcheck`.
Individual tests can be run with `make tests/{testName}.sh.test`.
### Integration tests
The integration tests are defined in the Nix flake under the `hydraJobs.tests` attribute.
These tests include everything that needs to interact with external services or run Nix in a non-trivial distributed setup.
Because these tests are expensive and require more than what the standard github-actions setup provides, they only run on the master branch (on <https://hydra.nixos.org/jobset/nix/master>).
You can run them manually with `nix build .#hydraJobs.tests.{testName}` or `nix-build -A hydraJobs.tests.{testName}`