Return result of yield from FakeFS block

Signed-off-by: Chris Wanstrath <chris@ozmm.org>

lib/fakefs/base.rb

@@ -31,7 +31,8 @@ end
 def FakeFS
   return ::FakeFS unless block_given?
   ::FakeFS.activate!
-  yield
+  result = yield
   ::FakeFS.deactivate!
+  result
 end
 

test/safe_test.rb

@@ -17,4 +17,13 @@ class FakeFSSafeTest < Test::Unit::TestCase
 
     assert ! File.exists?(path)
   end
+
+  def test_FakeFS_method_returns_value_of_yield
+    result = FakeFS do
+      File.open('myfile.txt', 'w') { |f| f.write "Yatta!" }
+      File.read('myfile.txt')
+    end
+
+    assert_equal result, "Yatta!"
+  end
 end