From 87044c57222fb485974062e2dd557e7b8abd8fff Mon Sep 17 00:00:00 2001
From: Matt Sturgeon <matt@sturgeon.me.uk>
Date: Sat, 1 Nov 2025 10:40:46 +0000
Subject: [PATCH] tests: explicitly define NIX_CONFIG

Ensure NIX_CONFIG is correctly configured for the tests command.

It is possible that someone may enable experimental features on an
ad-hoc basis, e.g. via the `--extra-experimental-features` CLI flag.
In this scenario, the tests script cannot assume they are already
enabled.

In the future, we may also wish to configure other things, like extra
binary substitutors.
---
 tests/package.nix | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/tests/package.nix b/tests/package.nix
index e8e767ce5..1d50ab8d6 100644
--- a/tests/package.nix
+++ b/tests/package.nix
@@ -10,6 +10,14 @@ writeShellApplication {
     python3
     fzf
   ];
+  runtimeEnv = {
+    # Explicitly enable experimental features, in case someone runs e.g.
+    #   nix run .#tests --extra-experimental-features 'nix-command flakes'
+    # without enabling them globally.
+    NIX_CONFIG = ''
+      experimental-features = nix-command flakes
+    '';
+  };
   text = ''
     exec python3 ${flake}/tests/tests.py "$@"
   '';