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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.

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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.

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Test structure

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

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Module tests

Verify that NixOS configurations evaluate without errors for various feature combinations:
TestDescription
eval-minimalMinimal NixOS modules import
eval-desktopDesktop feature flag
eval-developmentDevelopment feature flag
eval-all-featuresAll features enabled together
eval-themesTheme configurations
eval-keyboardKeyboard layouts and IME
eval-graphics-*GPU configurations (Intel, AMD, NVIDIA, PRIME)

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Library tests

Unit tests for lib functions using the assertTest helper.

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Writing tests

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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).

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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
'';

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CI pipeline

The GitHub Actions workflow (.github/workflows/validate.yml) runs three stages:
  1. Lints — nix fmt -- --ci (formatting check)
  2. Check — nix flake check (all evaluation tests)
  3. Build — Full system build (runs after lints and check pass)
Stages 1 and 2 run in parallel; stage 3 runs after both succeed. Builds use Cachix for caching.
Last modified on April 8, 2026