diff --git a/flake.nix b/flake.nix
index e3a05f8..e14cf17 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,7 +1,7 @@
 {
   description = "Declaratively update your data.";
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
-  outputs = { nixpkgs, ... }: let
+  outputs = { self, nixpkgs, ... }: let
     system = "x86_64-linux";
     pkgs = import nixpkgs { inherit system; };
     package = pkgs.stdenv.mkDerivation rec {
@@ -11,22 +11,46 @@
       src = ./.;
       deps = pkgs.callPackage ./build.zig.zon.nix {};
       nativeBuildInputs = [ pkgs.zig.hook pkgs.libgit2 pkgs.gpgme ];
-      zigBuildFlags = [ "--system" "${deps}" ];
+      zigBuildFlags = [
+        "--system" "${deps}"
+        "-Doptimize=Debug"
+      ];
     };
-    in {
+  in {
     lib = builtins.import ./lib.nix { pkgs = pkgs; };
     nixosModules = rec {
       fooud = { pkgs, lib, config, inputs, ... }: {
         options.programs.fooud.enable = lib.mkEnableOption ("fooud")
           // { default = true; };
         config = lib.mkIf config.programs.fooud.enable {
-          environment.systemPackages = [ pkgs.libgit2 pkgs.gpgme package ];
+          environment.systemPackages = [
+            pkgs.libgit2
+            pkgs.gpgme
+            pkgs.nix
+            package
+          ];
         };
       };
       default = fooud;
     };
-
-    # just x86 for now
     packages.${system} = rec { default = package; fooud = default; };
+
+    checks.${system}.build = let
+      package = self.packages.${system}.default;
+    in pkgs.runCommand "fooud-build" { buildInputs = [
+        pkgs.git
+        pkgs.nix
+      ]; } ''
+        mkdir repo
+        git -C repo init > /dev/null 2>&1
+        echo "hi" > repo/README.md
+        git -C repo config user.email "you@example.com" > /dev/null 2>&1
+        git -C repo config user.name "Your Name" > /dev/null 2>&1
+        git -C repo add . > /dev/null 2>&1
+        git -C repo commit -m "initial commit" > /dev/null 2>&1
+
+        # this check won't succeed until I find a way to run a chroot store
+        ${package}/bin/fooud --git repo --dest test
+        '';
   };
 }
diff --git a/src/NixStore.zig b/src/NixStore.zig
index fbbaed4..0fd66b9 100644
--- a/src/NixStore.zig
+++ b/src/NixStore.zig
@@ -4,41 +4,48 @@ const std = @import("std");
 
 const gpa = std.heap.page_allocator;
 
-const NixStoreError = error{
-    Failure,
-};
-
-pub fn add(path: []const u8) NixStoreError![]const u8 {
+/// Add a path to the store, this will copy the contents of path recursively
+/// into the store and return a (hopefully) valid store path. To try and keep
+/// this store path valid you should follow this with a call to realize() and
+/// then root the store path.
+pub fn add(path: []const u8) error{Failure}![]const u8 {
     const res = std.process.Child.run(.{
         .allocator = gpa,
         .argv = &[_][]const u8{ "nix", "store", "add", path },
-    }) catch return NixStoreError.Failure;
+    }) catch return error.Failure;
 
     return res.stdout[0 .. res.stdout.len - 1]; // to chop off the \n
 }
 
-pub fn realize(store_path: []const u8) NixStoreError!void {
+/// This tries to tell the store that a store_path should stick around a while
+/// longer, there's a chance that it doesn't listen and removes that store_path
+/// but in my testing it seemed to stick around.
+pub fn realize(store_path: []const u8) error{Failure}!void {
     _ = std.process.Child.run(.{
         .allocator = gpa,
         .argv = &[_][]const u8{ "nix-store", "--realize", store_path },
-    }) catch return NixStoreError.Failure;
+    }) catch return error.Failure;
     return;
 }
 
-pub fn root(store_path: []const u8, root_path: []const u8) NixStoreError!void {
+/// This tells the nix store to not gc our new store_path because it has a
+/// dependency at root_path and that only if root_path doesn't exist anymore
+/// it can delete store_path.
+pub fn root(store_path: []const u8, root_path: []const u8) error{Failure}!void {
     _ = std.process.Child.run(.{
         .allocator = gpa,
         .argv = &[_][]const u8{ "nix-store", "--add-root", root_path, "--indirect", store_path },
-    }) catch return NixStoreError.Failure;
+    }) catch return error.Failure;
     return;
 }
 
-pub fn delete(store_path: []const u8) NixStoreError!void {
+/// Delete a path from the store.
+pub fn delete(store_path: []const u8) error{Failure}!void {
     _ = std.process.Child.run(.{
         .allocator = gpa,
         .argv = &[_][]const u8{ "nix", "store", "delete", store_path },
     }) catch {
-        return NixStoreError.Failure;
+        return error.Failure;
     };
     return;
 }
diff --git a/src/main.zig b/src/main.zig
index 55423a5..aacd242 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -102,7 +102,7 @@ pub fn main() !void {
     // delete the old nix store path
     if (dest_old_store_path) |path| {
         std.log.info("deleting old store path: {s}", .{path});
-        NixStore.delete(path) catch |err| if (err == error.Failure) return err;
+        try NixStore.delete(path);
     }
 }