Backport stream header fix (#1959)

Resolve headers as body in ASGI mode

* Bump version to 19.12.3

* Update multidict==5.0.0

tests/test_keep_alive_timeout.py

@@ -230,8 +230,8 @@ async def handler3(request):
 
 def test_keep_alive_timeout_reuse():
     """If the server keep-alive timeout and client keep-alive timeout are
-     both longer than the delay, the client _and_ server will successfully
-     reuse the existing connection."""
+    both longer than the delay, the client _and_ server will successfully
+    reuse the existing connection."""
     try:
         loop = asyncio.new_event_loop()
         asyncio.set_event_loop(loop)

tests/test_response.py

@@ -232,6 +232,12 @@ def test_chunked_streaming_returns_correct_content(streaming_app):
     assert response.text == "foo,bar"
 
 
+@pytest.mark.asyncio
+async def test_chunked_streaming_returns_correct_content_asgi(streaming_app):
+    request, response = await streaming_app.asgi_client.get("/")
+    assert response.text == "4\r\nfoo,\r\n3\r\nbar\r\n0\r\n\r\n"
+
+
 def test_non_chunked_streaming_adds_correct_headers(non_chunked_streaming_app):
     request, response = non_chunked_streaming_app.test_client.get("/")
     assert "Transfer-Encoding" not in response.headers
@@ -239,6 +245,16 @@ def test_non_chunked_streaming_adds_correct_headers(non_chunked_streaming_app):
     assert response.headers["Content-Length"] == "7"
 
 
+@pytest.mark.asyncio
+async def test_non_chunked_streaming_adds_correct_headers_asgi(
+    non_chunked_streaming_app,
+):
+    request, response = await non_chunked_streaming_app.asgi_client.get("/")
+    assert "Transfer-Encoding" not in response.headers
+    assert response.headers["Content-Type"] == "text/csv"
+    assert response.headers["Content-Length"] == "7"
+
+
 def test_non_chunked_streaming_returns_correct_content(
     non_chunked_streaming_app,
 ):