use the body proxy to freeze headers

avoid freezing the headers until the web server has actually read data
from the body proxy.  Once the webserver has read data, then we should
throw an error if someone tries to set a header

1 files changed, 12 insertions, 2 deletions

diff --git a/actionpack/test/dispatch/live_response_test.rb b/actionpack/test/dispatch/live_response_test.rb
index 336fdd569b..512f3a8a7a 100644
--- a/actionpack/test/dispatch/live_response_test.rb
+++ b/actionpack/test/dispatch/live_response_test.rb
@@ -35,6 +35,7 @@ module ActionController
           @response.stream.close
         }
 
+        @response.await_commit
         @response.each do |part|
           assert_equal 'foo', part
           latch.release
@@ -59,21 +60,30 @@ module ActionController
         assert_nil @response.headers['Content-Length']
       end
 
-      def test_headers_cannot_be_written_after_write
+      def test_headers_cannot_be_written_after_webserver_reads
         @response.stream.write 'omg'
+        latch = ActiveSupport::Concurrency::Latch.new
 
+        t = Thread.new {
+          @response.stream.each do |chunk|
+            latch.release
+          end
+        }
+
+        latch.await
         assert @response.headers.frozen?
         e = assert_raises(ActionDispatch::IllegalStateError) do
           @response.headers['Content-Length'] = "zomg"
         end
 
         assert_equal 'header already sent', e.message
+        @response.stream.close
+        t.join
       end
 
       def test_headers_cannot_be_written_after_close
         @response.stream.close
 
-        assert @response.headers.frozen?
         e = assert_raises(ActionDispatch::IllegalStateError) do
           @response.headers['Content-Length'] = "zomg"
         end