diff --git a/Library/Homebrew/test/test_ENV.rb b/Library/Homebrew/test/test_ENV.rb
index 1a1dd922bd..8c1a725196 100644
--- a/Library/Homebrew/test/test_ENV.rb
+++ b/Library/Homebrew/test/test_ENV.rb
@@ -27,7 +27,7 @@ class EnvironmentTests < Test::Unit::TestCase
     assert_equal ENV['OBJC'], ENV['CC']
   end
 
-  def test_with_build_environment
+  def test_with_build_environment_restores_env
     before = ENV.to_hash
     ENV.with_build_environment do
       ENV['foo'] = 'bar'
@@ -35,4 +35,16 @@ class EnvironmentTests < Test::Unit::TestCase
     assert_nil ENV['foo']
     assert_equal before, ENV.to_hash
   end
+
+  def test_with_build_environment_ensures_env_restored
+    ENV.expects(:replace).with(ENV.to_hash)
+    begin
+      ENV.with_build_environment { raise Exception }
+    rescue Exception
+    end
+  end
+
+  def test_with_build_environment_returns_block_value
+    assert_equal 1, ENV.with_build_environment { 1 }
+  end
 end