Testing - Jylhis Docs

Tests in Marchyo are fast evaluation-based checks that verify NixOS configurations evaluate without errors. They don’t build any derivations, so they complete in under a minute.

Running tests

# Run all tests
nix flake check

# List available tests
nix eval .#checks.x86_64-linux --apply builtins.attrNames

There is no way to run a single test in isolation — nix flake check runs them all.

Test structure

tests/
  default.nix        # Entry point combining all tests
  module-tests.nix   # Module evaluation tests
  lib-tests.nix      # Library function unit tests

Module tests

Verify that NixOS configurations evaluate without errors for various feature combinations:

Test	Description
`eval-minimal`	Minimal NixOS modules import
`eval-desktop`	Desktop feature flag
`eval-development`	Development feature flag
`eval-all-features`	All features enabled together
`eval-themes`	Theme configurations
`eval-keyboard`	Keyboard layouts and IME
`eval-graphics-*`	GPU configurations (Intel, AMD, NVIDIA, PRIME)

Library tests

Unit tests for lib functions using the assertTest helper.

Writing tests

Module evaluation test

Add to tests/module-tests.nix:

eval-my-feature = testNixOS "my-feature" (withTestUser {
  marchyo.myFeature.enable = true;
});

The testNixOS helper evaluates the NixOS config without building derivations. The withTestUser helper merges your config with a minimal bootable config (grub disabled, root filesystem, stateVersion).

Library test

Add to tests/lib-tests.nix:

test-my-function = pkgs.runCommand "test-my-function" { } ''
  result=$(nix eval --raw --expr '(import ../lib { inherit (pkgs) lib; }).myFunction "input"')
  [[ "$result" == "expected" ]] || exit 1
  touch $out
'';

CI pipeline

The GitHub Actions workflow (.github/workflows/validate.yml) runs three stages:

Lint — nix fmt -- --ci plus a flake.lock / devenv.lock rev-parity check on a single Linux runner.
Check — nix flake check --accept-flake-config matrix across x86_64-linux, aarch64-linux, and aarch64-darwin.
Build — nix build .#nixosConfigurations.x86_64.config.system.build.toplevel (runs after lint and check pass).

Stages 1 and 2 run in parallel; stage 3 runs after both succeed. Concurrency groups cancel superseded PR runs automatically. Builds use Cachix (jylhis cache). A separate .github/workflows/pages.yml workflow deploys the docs to GitHub Pages, scoped via path filters to docs/** and flake sources so unrelated commits don’t trigger redeploys.

​Running tests

​Test structure

​Module tests

​Library tests

​Writing tests

​Module evaluation test

​Library test

​CI pipeline