diff --git a/lib/tests/formulae.rb b/lib/tests/formulae.rb
index 6165e905..41601777 100644
--- a/lib/tests/formulae.rb
+++ b/lib/tests/formulae.rb
@@ -242,7 +242,7 @@ def bottle_reinstall_formula(formula, new_formula, args:)
 
         # This is needed where sparse files may be handled (bsdtar >=3.0).
         # We use gnu-tar with sparse files disabled when --only-json-tab is passed.
-        ENV["HOMEBREW_BOTTLE_SUDO_PURGE"] = "1" if MacOS.version >= :catalina && !args.only_json_tab?
+        ENV["HOMEBREW_BOTTLE_SUDO_PURGE"] = "1" if OS.mac? && MacOS.version >= :catalina && !args.only_json_tab?
 
         bottle_args = ["--verbose", "--json", formula.full_name]
         bottle_args << "--keep-old" if args.keep_old? && !new_formula