test: move nix files

These are too much clutter. Move them to test directory until the test suite replacement is upstreamed.

Signed-off-by: Ophestra <cat@gensokyo.uk>

test/hsu.nix

@@ -0,0 +1,23 @@
+{
+  lib,
+  buildGoModule,
+  hakurei ? abort "hakurei package required",
+}:
+
+buildGoModule {
+  pname = "${hakurei.pname}-hsu";
+  inherit (hakurei) version;
+
+  src = ../cmd/hsu;
+  inherit (hakurei) vendorHash;
+  env.CGO_ENABLED = 0;
+
+  preBuild = ''
+    go mod init hsu >& /dev/null
+  '';
+
+  ldflags = lib.attrsets.foldlAttrs (
+    ldflags: name: value:
+    ldflags ++ [ "-X main.${name}=${value}" ]
+  ) [ "-s -w" ] { hakureiPath = "${hakurei}/libexec/hakurei"; };
+}