add TestEmptyYield

--HG--
extra : transplant_source : %D3%23%3F%1ET%96%24%89%D7%D4z%C4%A9%BBv%7Ct%01%AB%2A

greentest/wsgi_test.py

@@ -517,6 +517,23 @@ class TestError_after_start_response(TestError):
         start_response('200 OK', [('Content-Type', 'text/plain')])
         raise ExpectedException
 
+class TestEmptyYield(TestCase):
+    @staticmethod
+    def application(env, start_response):
+        start_response('200 OK', [('Content-Type', 'text/plain')])
+        
+        yield ""
+        yield ""
+        
+    def test_err(self):
+        fd = self.connect().makefile(bufsize=1)
+        fd.write('GET / HTTP/1.1\r\nHost: localhost\r\nConnection: close\r\n\r\n')
+        st, h, body = read_http(fd)
+        assert body==""
+
+        garbage = fd.read()
+        self.assert_(garbage=="", "got garbage: %r" % garbage)
+            
 
 class HTTPRequest(urllib2.Request):
     """Hack urllib2.Request to support PUT and DELETE methods."""