treewide cleanups and refactoring for initial tests (#157)

- [x] refactor lib into separate files, similar to NixOS/nixpkgs/lib.
- [x] refactor ci to automatically generate derivations from flake outputs
- [x] remove cluttered indirection statements throughout the codebase
- [x] refactor hosts to allow for upcoming integration tests
- [x] improve ambiguity in the existing docs 
- [x] add [BORS](https://bors.tech) support
- [x] add initial integration test
- [x] write tests documentation
- [x] test lib
- [x] improve version string generation, and do so automatically for pkgs/flake.nix sources

Clean up the codebase as best we can in preparation for #152 and add tests. From now on, all PRs will be merged with BORS.

.envrc

@@ -1,2 +1,2 @@
-watch_file **/*.nix
+watch_file shell/* flake.nix
 use flake || use nix

README.md

@@ -1,29 +1,31 @@
-[![Build](https://img.shields.io/github/checks-status/divnix/devos/core)](https://hercules-ci.com/github/divnix/devos/jobs)
+[![Bors enabled](https://bors.tech/images/badge_small.svg)](https://app.bors.tech/repositories/32678)
 [![MIT License](https://img.shields.io/github/license/divnix/devos)][mit]
 [![NixOS 20.09](https://img.shields.io/badge/NixOS-v20.09-blue.svg?style=flat&logo=NixOS&logoColor=white)](https://nixos.org)
 
 > #### ⚠ Advisory ⚠
-> DevOS leverages the [flakes][flakes] feature available via an _experimental_
-> branch of [nix][nix]. Until nix 3.0 is released, this project should be
-> considered unstable, though quite usable as flakes have been maturing
-> _well_
-> [for a while](https://github.com/divnix/devos/tree/17713c22d07c54525c728c62060a0428b76dee3b).
+> DevOS requires the [flakes][flakes] feature available via an _experimental_
+> branch of [nix][nix]. Until nix 3.0 is released, this project
+> should be considered unstable, though quite usable as flakes have been
+> maturing _well_ [for a while](https://github.com/divnix/devos/tree/17713c22d07c54525c728c62060a0428b76dee3b).
 
 # Introduction
 DevOS grants a simple way to use, deploy and manage [NixOS][nixos] systems for
-personal and productive use. It does this by providing a convenient repository
-structure, integrating several popular projects like
-[home-manager][home-manager], and [devshell][devshell], and offering useful
-conveniences like
+personal and productive use. A sane repository structure is provided,
+integrating several popular projects like [home-manager][home-manager],
+[devshell][devshell], and [more](./doc/integrations).
+
+Stiving for ___nix first™___ solutions with unobstrusive implementations,
+a [flake centric][flake-doc] approach is taken for useful conveniences such as
 [automatic source updates](./pkgs#automatic-source-updates).
 
-Skip the indeterminate nature of other systems, _and_ the perceived difficulty
-of Nix. It's easier than you think!
+Skip the indeterminate nature of other systems, _and_ the perceived
+tedium of bootstrapping Nix. It's easier than you think!
 
-### Status
-Alpha. A lot of the implementation is less than perfect, and huge redesigns
-_will_ happen. There are unstable versions (0._x_._x_) to help users keep
-track of changes and progress.
+### Status: Alpha
+A lot of the implementation is less than perfect, and huge
+[redesigns](https://github.com/divnix/devos/issues/152) _will_ happen. There
+are unstable versions (0._x_._x_) to help users keep track of changes and
+progress.
 
 ## Getting Started
 Check out the [guide](https://devos.divnix.com/doc/start) to get up and running.
@@ -36,8 +38,8 @@ make critical comments about the [code][please]. 😜
 NixOS provides an amazing abstraction to manage our environment, but that new
 power can sometimes bring feelings of overwhelm and confusion. Having a turing
 complete system can easily lead to unlimited complexity if we do it wrong.
-Instead, we should have a community consensus on how to manage a NixOS system.
-Help us reach that goal!
+Instead, we should have a community consensus on how to manage a NixOS system
+and its satellite projects, from which best practices can evolve.
 
 ___The future is declarative! 🎉___
 
@@ -73,6 +75,7 @@ DevOS is licensed under the [MIT License][mit].
 [nixos]: https://nixos.org/manual/nixos/stable
 [home-manager]: https://nix-community.github.io/home-manager
 [flakes]: https://nixos.wiki/wiki/Flakes
+[flake-doc]: https://github.com/NixOS/nix/blob/master/src/nix/flake.md
 [core]: https://github.com/divnix/devos
 [community]: https://github.com/divnix/devos/tree/community
 [dotfiles]: https://github.com/hlissner/dotfiles

SUMMARY.md

@@ -16,6 +16,7 @@
   - [Profiles](./profiles/README.md)
   - [Secrets](./secrets/README.md)
   - [Suites](./suites/README.md)
+  - [Tests](./tests/README.md)
   - [Users](./users/README.md)
 - [flk](./doc/flk/index.md)
   - [up](./doc/flk/up.md)
@@ -25,6 +26,6 @@
   - [install](./doc/flk/install.md)
   - [home](./doc/flk/home.md)
 - [Integrations](doc/integrations/index.md)
-  - [deploy-rs](./doc/integrations/deploy.md)
-  - [hercules-ci](./doc/integrations/hercules.md)
+  - [Deploy RS](./doc/integrations/deploy.md)
+  - [Hercules CI](./doc/integrations/hercules.md)
 - [Contributing](./doc/README.md)

bors.toml

@@ -0,0 +1,12 @@
+status = [
+  "ci/hercules/evaluation",
+  "ci/hercules/derivations"
+]
+
+required_approvals = 1
+
+up_to_date_approvals = true
+
+delete_merged_branches = true
+
+use_squash_merge = true

default.nix

@@ -1,8 +1,8 @@
 let
-  inherit (default.inputs.nixos.lib) recurseIntoAttrs;
+  inherit (default.inputs.nixos) lib;
 
   default = (import ./compat).defaultNix;
 in
-builtins.mapAttrs (_: v: recurseIntoAttrs v) default.packages // {
+builtins.mapAttrs (_: v: lib.recurseIntoAttrs v) default.packages // {
   shell = import ./shell.nix;
 }

doc/README.md

@@ -4,6 +4,8 @@ relevant docs. Each directory contains its own README.md, which will
 automatically be pulled into the [mdbook](https://devos.divnix.com). The book is
 rendered on every change, so the docs should always be up to date.
 
+We also use [BORS](https://bors.tech) to ensure that all pull requests pass the
+test suite once at least one review is completed.
 
 ## Community PRs
 While much of your work in this template may be idiosyncratic in nature. Anything

flake.nix

@@ -27,65 +27,57 @@
       srcs.url = "path:./pkgs";
     };
 
-  outputs =
-    inputs@{ ci-agent
-    , deploy
-    , devshell
-    , home
-    , nixos
-    , nixos-hardware
-    , nur
-    , override
-    , self
-    , utils
-    , ...
-    }:
+  outputs = inputs@{ deploy, nixos, nur, self, utils, ... }:
     let
-      inherit (utils.lib) eachDefaultSystem flattenTreeSystem;
-      inherit (nixos.lib) recursiveUpdate;
-      inherit (self.lib) overlays nixosModules genPackages genPkgs
-        genHomeActivationPackages mkNodes;
+      inherit (self) lib;
+      inherit (lib) os;
 
       extern = import ./extern { inherit inputs; };
 
-      pkgs' = genPkgs { inherit self; };
+      pkgs' = os.mkPkgs { inherit self; };
 
       outputs =
         let
           system = "x86_64-linux";
           pkgs = pkgs'.${system};
         in
         {
-          inherit nixosModules overlays;
-
           nixosConfigurations =
-            import ./hosts (recursiveUpdate inputs {
+            import ./hosts (nixos.lib.recursiveUpdate inputs {
               inherit pkgs system extern;
               inherit (pkgs) lib;
             });
 
+          nixosModules =
+            let moduleList = import ./modules/module-list.nix;
+            in lib.pathsToImportedAttrs moduleList;
+
           overlay = import ./pkgs;
+          overlays = lib.pathsToImportedAttrs (lib.pathsIn ./overlays);
 
           lib = import ./lib { inherit nixos pkgs; };
 
           templates.flk.path = ./.;
-
           templates.flk.description = "flk template";
-
           defaultTemplate = self.templates.flk;
 
-          deploy.nodes = mkNodes deploy self.nixosConfigurations;
+          deploy.nodes = os.mkNodes deploy self.nixosConfigurations;
 
-          checks = builtins.mapAttrs
-            (system: deployLib: deployLib.deployChecks self.deploy)
-            deploy.lib;
+          checks =
+            let
+              tests = import ./tests { inherit self pkgs; };
+              deployChecks = builtins.mapAttrs
+                (system: deployLib: deployLib.deployChecks self.deploy)
+                deploy.lib;
+            in
+            nixos.lib.recursiveUpdate tests deployChecks;
         };
 
-      systemOutputs = eachDefaultSystem (system:
+      systemOutputs = utils.lib.eachDefaultSystem (system:
         let pkgs = pkgs'.${system}; in
         {
-          packages = flattenTreeSystem system
-            (genPackages {
+          packages = utils.lib.flattenTreeSystem system
+            (os.mkPackages {
               inherit self pkgs;
             });
 
@@ -94,9 +86,9 @@
           };
 
           legacyPackages.hmActivationPackages =
-            genHomeActivationPackages { inherit self; };
+            os.mkHomeActivation { inherit self; };
         }
       );
     in
-    recursiveUpdate outputs systemOutputs;
+    nixos.lib.recursiveUpdate outputs systemOutputs;
 }

hosts/default.nix

@@ -2,89 +2,96 @@
 , home
 , lib
 , nixos
-, nixos-hardware
 , override
 , pkgs
 , self
 , system
 , ...
 }:
 let
-  inherit (lib.flk) recImport nixosSystemExtended defaultImports;
-  inherit (builtins) attrValues removeAttrs;
+  inherit (lib) dev;
 
   suites = import ../suites { inherit lib; };
 
-  config = hostName:
-    nixosSystemExtended {
-      inherit system;
-
-      specialArgs = extern.specialArgs // { inherit suites; };
-
-      modules =
+  modules =
+    let
+      core = ../profiles/core;
+      modOverrides = { config, overrideModulesPath, ... }:
         let
-          core = ../profiles/core;
-
-          modOverrides = { config, overrideModulesPath, ... }:
-            let
-              overrides = import ../overrides;
-              inherit (overrides) modules disabledModules;
-            in
-            {
-              disabledModules = modules ++ disabledModules;
-              imports = map
-                (path: "${overrideModulesPath}/${path}")
-                modules;
-            };
-
-          global = {
-            home-manager.useGlobalPkgs = true;
-            home-manager.useUserPackages = true;
-
-            hardware.enableRedistributableFirmware = lib.mkDefault true;
-
-            networking.hostName = hostName;
-
-            nix.nixPath = [
-              "nixpkgs=${nixos}"
-              "nixos-config=${self}/compat/nixos"
-              "home-manager=${home}"
-            ];
-
-            nixpkgs = { inherit pkgs; };
-
-            nix.registry = {
-              devos.flake = self;
-              nixos.flake = nixos;
-              override.flake = override;
-            };
-
-            system.configurationRevision = lib.mkIf (self ? rev) self.rev;
-          };
-
-          local = {
-            require = [
-              "${toString ./.}/${hostName}.nix"
-            ];
-          };
-
-          # Everything in `./modules/list.nix`.
-          flakeModules =
-            attrValues self.nixosModules;
-
+          overrides = import ../overrides;
+          inherit (overrides) modules disabledModules;
         in
-        flakeModules ++ [
-          core
-          global
-          local
-          modOverrides
-        ] ++ extern.modules;
-
+        {
+          disabledModules = modules ++ disabledModules;
+          imports = map
+            (path: "${overrideModulesPath}/${path}")
+            modules;
+        };
+
+      global = {
+        home-manager.useGlobalPkgs = true;
+        home-manager.useUserPackages = true;
+
+        hardware.enableRedistributableFirmware = lib.mkDefault true;
+
+        nix.nixPath = [
+          "nixpkgs=${nixos}"
+          "nixos-config=${self}/compat/nixos"
+          "home-manager=${home}"
+        ];
+
+        nixpkgs = { inherit pkgs; };
+
+        nix.registry = {
+          devos.flake = self;
+          nixos.flake = nixos;
+          override.flake = override;
+        };
+
+        system.configurationRevision = lib.mkIf (self ? rev) self.rev;
+      };
+
+      # Everything in `./modules/list.nix`.
+      flakeModules =
+        builtins.attrValues self.nixosModules;
+
+    in
+    flakeModules ++ [
+      core
+      global
+      modOverrides
+    ] ++ extern.modules;
+
+  specialArgs = extern.specialArgs // { inherit suites; };
+
+  mkHostConfig = hostName:
+    let
+      local = {
+        require = [
+          "${toString ./.}/${hostName}.nix"
+        ];
+
+        networking = { inherit hostName; };
+      };
+    in
+    dev.os.devosSystem {
+      inherit system specialArgs;
+
+      modules = modules ++ [
+        local
+        {
+          lib = { inherit specialArgs; };
+          lib.testModule = {
+            imports = modules;
+          };
+        }
+      ];
     };
 
-  hosts = recImport {
-    dir = ./.;
-    _import = config;
-  };
+  hosts = dev.os.recImport
+    {
+      dir = ./.;
+      _import = mkHostConfig;
+    };
 in
 hosts