From 5b3cf28bbcdb00ef1d02cec3b1d8907c2b89ff82 Mon Sep 17 00:00:00 2001
From: Bo Anderson <mail@boanderson.me>
Date: Mon, 24 Apr 2023 17:05:38 +0100
Subject: [PATCH] utils/gems: don't silently install gems during tests

---
 Library/Homebrew/utils/gems.rb | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Library/Homebrew/utils/gems.rb b/Library/Homebrew/utils/gems.rb
index c7d8efc480..e8d7eb356e 100644
--- a/Library/Homebrew/utils/gems.rb
+++ b/Library/Homebrew/utils/gems.rb
@@ -155,6 +155,12 @@ module Homebrew
     invalid_groups = groups - valid_gem_groups
     raise ArgumentError, "Invalid gem groups: #{invalid_groups.join(", ")}" unless invalid_groups.empty?
 
+    # tests should not modify the state of the repo
+    if ENV["HOMEBREW_TESTS"]
+      setup_gem_environment!
+      return
+    end
+
     install_bundler!
 
     require "settings"