diff --git a/Library/Homebrew/test/sandbox_test.rb b/Library/Homebrew/test/sandbox_test.rb
index 21a3ca8c40..a633defce2 100644
--- a/Library/Homebrew/test/sandbox_test.rb
+++ b/Library/Homebrew/test/sandbox_test.rb
@@ -15,11 +15,11 @@ class SandboxTest < Homebrew::TestCase
     f2 = formula { url "bar-1.0" }
     f2.stubs(:tap).returns(Tap.fetch("test/tap"))
 
-    ARGV.stubs(:sandbox?).returns true
+    ENV["HOMEBREW_SANDBOX"] = "1"
     assert Sandbox.formula?(f),
       "Formulae should be sandboxed if --sandbox was passed."
 
-    ARGV.stubs(:sandbox?).returns false
+    ENV.delete("HOMEBREW_SANDBOX")
     assert Sandbox.formula?(f),
       "Formulae should be sandboxed if in a sandboxed tap."
     refute Sandbox.formula?(f2),
@@ -27,7 +27,7 @@ class SandboxTest < Homebrew::TestCase
   end
 
   def test_test?
-    ARGV.stubs(:no_sandbox?).returns false
+    ENV.delete("HOMEBREW_NO_SANDBOX")
     assert Sandbox.test?,
       "Tests should be sandboxed unless --no-sandbox was passed."
   end