diff --git a/common.mk b/common.mk
index 2a1e436040..bb193320b8 100644
--- a/common.mk
+++ b/common.mk
@@ -1671,12 +1671,8 @@ test-bundler-prepare: $(TEST_RUNNABLE)-test-bundler-prepare
 no-test-bundler-prepare: no-test-bundler-precheck
 yes-test-bundler-prepare: yes-test-bundler-precheck
 	$(ACTIONS_GROUP)
-	$(XRUBY) -C $(srcdir) -Ilib \
-		-e 'ENV["GEM_HOME"] = File.expand_path(".bundle")' \
-		-e 'ENV["BUNDLE_APP_CONFIG"] = File.expand_path(".bundle")' \
-		-e 'ENV["BUNDLE_PATH__SYSTEM"] = "true"' \
-		-e 'ENV["BUNDLE_WITHOUT"] = "lint doc"' \
-		-e 'load "spec/bundler/support/bundle.rb"' -- install --quiet --gemfile=tool/bundler/dev_gems.rb
+	$(XRUBY) -C $(srcdir) -Ilib -r./tool/lib/bundle_env.rb \
+		spec/bin/bundle install --quiet --gemfile=tool/bundler/dev_gems.rb
 	$(ACTIONS_ENDGROUP)
 
 RSPECOPTS = -r formatter_overrides
diff --git a/tool/lib/bundle_env.rb b/tool/lib/bundle_env.rb
new file mode 100644
index 0000000000..9ad5ea220b
--- /dev/null
+++ b/tool/lib/bundle_env.rb
@@ -0,0 +1,4 @@
+ENV["GEM_HOME"] = File.expand_path("../../.bundle", __dir__)
+ENV["BUNDLE_APP_CONFIG"] = File.expand_path("../../.bundle", __dir__)
+ENV["BUNDLE_PATH__SYSTEM"] = "true"
+ENV["BUNDLE_WITHOUT"] = "lint doc"