diff --git a/Library/Homebrew/dev-cmd/tests.rb b/Library/Homebrew/dev-cmd/tests.rb
index 41a94170b1..8278514e96 100644
--- a/Library/Homebrew/dev-cmd/tests.rb
+++ b/Library/Homebrew/dev-cmd/tests.rb
@@ -58,6 +58,7 @@ module Homebrew
       ENV.delete("HOMEBREW_NO_EMOJI")
       ENV.delete("HOMEBREW_DEVELOPER")
       ENV.delete("HOMEBREW_PRY")
+      ENV.delete("HOMEBREW_BAT")
       ENV["HOMEBREW_NO_ANALYTICS_THIS_RUN"] = "1"
       ENV["HOMEBREW_NO_COMPAT"] = "1" if args.no_compat?
       ENV["HOMEBREW_TEST_GENERIC_OS"] = "1" if args.generic?