doc/meta: Mention --version as a good usecase for installCheckPhase

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Doron Behar 2024-05-29 15:29:39 +03:00
parent f4e6f41b72
commit 444c2b6dd0

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@ -129,9 +129,29 @@ Note that Hydra and [`nixpkgs-review`](https://github.com/Mic92/nixpkgs-review)
#### Package tests {#var-meta-tests-packages}
Tests that are part of the source package are often executed in the `installCheckPhase`.
Tests that are part of the source package are often executed in the `installCheckPhase`. This phase is also suitable for performing a `--version` test for packages that support such flag. Here's an example:
Prefer `passthru.tests` for tests that are introduced in nixpkgs because:
```nix
# Say the package is git
stdenv.mkDerivation(finalAttrs: {
pname = "git";
version = "...";
# ...
doInstallCheck = true;
installCheckPhase = ''
runHook preInstallCheck
echo checking if 'git --version' mentions ${finalAttrs.version}
$out/bin/git --version | grep ${finalAttrs.version}
runHook postInstallCheck
'';
# ...
})
```
Most programs distributed by Nixpkgs support such a `--version` flag, and it can help give confidence that the package at least got compiled properly. However, tests that are slightly non trivial will better fit into `passthru.tests`, because:
* `passthru.tests` tests the 'real' package, independently from the environment in which it was built
* We can run and debug a `passthru.tests` independently, after the package was built (useful if it takes a long time).