{
  description = "Testing mastodon configurations";

  inputs = {
    nixpkgs.url = "github:radvendii/nixpkgs/nixos_rebuild_tests";
  };

  outputs = { self, nixpkgs }:
  let
    system = "x86_64-linux";
    pkgs = nixpkgs.legacyPackages.${system};
  in {

    nixosModules = {
      ## Fediversity modules
      fediversity = {
        imports = [ ./fediversity ];

        services.pixelfed.package = pkgs.pixelfed.overrideAttrs (old: {
          patches = (old.patches or [ ]) ++ [ ./fediversity/pixelfed-group-permissions.patch ];
        });
      };

      ## VM-specific modules
      interactive-vm = {
        imports = [
          ./vm/interactive-vm.nix
          self.nixosModules.fediversity
        ];
      };
      mastodon-vm = {
        imports = [
          ./vm/mastodon-vm.nix
          self.nixosModules.fediversity
        ];
      };
      peertube-vm = {
        imports = [
          ./vm/peertube-vm.nix
          self.nixosModules.fediversity
        ];
      };
      pixelfed-vm = {
        imports = [
          ./vm/pixelfed-vm.nix
          self.nixosModules.fediversity
        ];
      };
    };

    nixosConfigurations = {
      mastodon = nixpkgs.lib.nixosSystem {
        inherit system;
        modules = with self.nixosModules; [ fediversity interactive-vm mastodon-vm ];
      };

      peertube = nixpkgs.lib.nixosSystem {
        inherit system;
        modules = with self.nixosModules; [ fediversity interactive-vm peertube-vm ];
      };

      pixelfed = nixpkgs.lib.nixosSystem {
        inherit system;
        modules = with self.nixosModules; [ fediversity interactive-vm pixelfed-vm ];
      };

      all = nixpkgs.lib.nixosSystem {
        inherit system;
        modules = with self.nixosModules; [
          fediversity
          interactive-vm
          peertube-vm
          pixelfed-vm
          mastodon-vm
        ];
      };
    };

    checks.${system} = {
      mastodon-garage = import ./tests/mastodon-garage.nix { inherit pkgs self; };
      pixelfed-garage = import ./tests/pixelfed-garage.nix { inherit pkgs self; };
    };

    devShells.${system}.default = pkgs.mkShell {
      inputs = with pkgs; [
        nil
      ];
    };
  };
}