[nix] move test to derivation inside gcd vcs

For all chipsalliance CI runner, RestrictNamespaces and RestrictSUIDSGID
properties are set for best safety ensurance. So running VCS directly
inside the GitHub Runner is not possible.

This commit give an example of how to get out of the boundary of the
GitHub Action by integrating all simulation into derivation.

Signed-off-by: Avimitin <dev@avimit.in>

.github/workflows/main.yml

@@ -56,7 +56,7 @@ jobs:
           ref: ${{ github.event.pull_request.head.sha }}
       - name: "Run VCS"
         run: |
-          nix run '.#gcd.vcs' --impure
+          nix build '.#gcd.vcs.tests' --impure
 
   run-verilator:
     name: "Run Verilator"

templates/chisel/nix/gcd/vcs.nix

@@ -1,9 +1,19 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: 2024 Jiuyang Liu <liu@jiuyang.me>
 
-{ lib, bash, stdenv, rtl, dpi-lib, vcs-fhs-env }:
-let binName = "gcd-vcs-simulator";
-in stdenv.mkDerivation {
+{ lib
+, bash
+, stdenv
+, rtl
+, dpi-lib
+, vcs-fhs-env
+, runCommand
+}:
+
+let
+  binName = "gcd-vcs-simulator";
+in
+stdenv.mkDerivation (finalAttr: {
   name = "vcs";
 
   # Add "sandbox = relaxed" into /etc/nix/nix.conf, and run `systemctl restart nix-daemon`
@@ -46,6 +56,12 @@ in stdenv.mkDerivation {
     inherit vcs-fhs-env;
     inherit dpi-lib;
     inherit rtl;
+
+    tests.simple-sim = runCommand "${binName}-test" { __noChroot = true; } ''
+      # Combine stderr and stdout and redirect them to tee
+      # So that we can have log saving to output and also printing to stdout
+      ${finalAttr.finalPackage}/bin/${binName} &> >(tee $out)
+    '';
   };
 
   shellHook = ''
@@ -71,4 +87,4 @@ in stdenv.mkDerivation {
 
     runHook postInstall
   '';
-}
+})