From e18d3fb2804908fc00629e9139059d26a3ff4dcb Mon Sep 17 00:00:00 2001
From: Matt Sturgeon <matt@sturgeon.me.uk>
Date: Thu, 29 May 2025 15:17:45 +0100
Subject: [PATCH] flake/ci: add `ci.buildbot` output
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Adds top-level and per-system `ci.buildbot` option for defining tests to
build on buildbot.

These are exposed as the `ci.buildbot.«system»` flake output.
---
 flake/ci.nix           | 43 ++++++++++++++++++++++++++++++++++++++++++
 flake/default.nix      |  2 ++
 flake/dev/devshell.nix |  1 +
 3 files changed, 46 insertions(+)
 create mode 100644 flake/ci.nix

diff --git a/flake/ci.nix b/flake/ci.nix
new file mode 100644
index 00000000..69153c69
--- /dev/null
+++ b/flake/ci.nix
@@ -0,0 +1,43 @@
+{ lib, config, ... }:
+let
+  inherit (lib)
+    mapAttrs
+    types
+    ;
+
+  buildbotOpt = lib.mkOption {
+    type = types.lazyAttrsOf types.package;
+    default = { };
+    description = ''
+      A set of tests for [buildbot] to run.
+
+      [buildbot]: https://buildbot.nix-community.org
+    '';
+  };
+in
+{
+  perSystem = {
+    # Declare per-system CI options
+    options.ci = {
+      buildbot = buildbotOpt;
+    };
+  };
+
+  flake = {
+    # Declare top-level CI options
+    options.ci = {
+      buildbot = lib.mkOption {
+        type = types.lazyAttrsOf buildbotOpt.type;
+        default = { };
+        description = ''
+          See `perSystem.ci.buildbot` for description and examples.
+        '';
+      };
+    };
+
+    # Transpose per-system CI outputs to the top-level
+    config.ci = {
+      buildbot = mapAttrs (_: sysCfg: sysCfg.ci.buildbot) config.allSystems;
+    };
+  };
+}
diff --git a/flake/default.nix b/flake/default.nix
index 58db3e79..36875c31 100644
--- a/flake/default.nix
+++ b/flake/default.nix
@@ -8,6 +8,7 @@
 {
   imports = [
     ./flake-modules
+    ./ci.nix
     ./lib.nix
     ./legacy-packages.nix
     ./nixvim-configurations.nix
@@ -31,6 +32,7 @@
 
   # Specify which outputs are defined by which partitions
   partitionedAttrs = {
+    ci = "dev";
     checks = "dev";
     devShells = "dev";
     formatter = "dev";
diff --git a/flake/dev/devshell.nix b/flake/dev/devshell.nix
index 06930895..c12a050d 100644
--- a/flake/dev/devshell.nix
+++ b/flake/dev/devshell.nix
@@ -29,6 +29,7 @@
             {
               name = "checks";
               help = "Run all nixvim checks";
+              # TODO: run tests from the `ci` flake output too?
               command = ''
                 echo "=> Running all nixvim checks..."