test: add Connection: close tests for issue #439

Add tests to verify Connection: close responses are handled correctly:
- connection_close_response: basic Connection: close response
- connection_close_large_body: 100KB body with Connection: close

Also adds /connection-close/:size endpoint to test_http_resource.

These tests confirm Connection: close handling works correctly.

Author: benoitc

test/hackney_integration_tests.erl

@@ -17,6 +17,8 @@ all_tests() ->
    fun not_modified_body_read_then_next_request/0,
    fun chunked_body_read_then_next_request/0,
    fun chunked_large_body_read/0,
+   fun connection_close_response/0,
+   fun connection_close_large_body/0,
    fun basic_auth_request_failed/0,
    fun basic_auth_request/0,
    fun basic_auth_url_request/0,
@@ -142,6 +144,26 @@ chunked_large_body_read() ->
     {ok, Body} = hackney:body(Client),
     ?assertEqual(102400, byte_size(Body)).
 
+%% Test for issue #439: Connection: close responses should not be lost
+%% Tests that responses with Connection: close header are received correctly
+connection_close_response() ->
+    URL = url(<<"/connection-close">>),
+    {ok, Status, Headers, Client} = hackney:request(get, URL, [], <<>>, []),
+    ?assertEqual(200, Status),
+    %% Verify Connection: close header
+    ?assertEqual(<<"close">>, hackney_headers:get_value(<<"connection">>, hackney_headers:from_list(Headers))),
+    {ok, Body} = hackney:body(Client),
+    ?assertEqual(<<"{\"connection\": \"close\"}">>, Body).
+
+%% Test larger Connection: close response
+connection_close_large_body() ->
+    URL = url(<<"/connection-close/102400">>),
+    {ok, Status, Headers, Client} = hackney:request(get, URL, [], <<>>, [{recv_timeout, 10000}]),
+    ?assertEqual(200, Status),
+    ?assertEqual(<<"close">>, hackney_headers:get_value(<<"connection">>, hackney_headers:from_list(Headers))),
+    {ok, Body} = hackney:body(Client),
+    ?assertEqual(102400, byte_size(Body)).
+
 basic_auth_request() ->
     URL = url(<<"/basic-auth/username/password">>),
     %% Use application variable instead of per-request option

test/test_http_resource.erl

@@ -130,6 +130,17 @@ handle_request(<<"GET">>, <<"/connection-close">>, Req, State) ->
     }, <<"{\"connection\": \"close\"}">>, Req),
     {ok, Req2, State};
 
+%% GET /connection-close/:size - return large body with Connection: close
+%% For testing issue #439 - responses with connection close sometimes lost
+handle_request(<<"GET">>, <<"/connection-close/", SizeBin/binary>>, Req, State) ->
+    Size = binary_to_integer(SizeBin),
+    Body = binary:copy(<<"X">>, Size),
+    Req2 = cowboy_req:reply(200, #{
+        <<"content-type">> => <<"application/octet-stream">>,
+        <<"connection">> => <<"close">>
+    }, Body, Req),
+    {ok, Req2, State};
+
 %% GET /inform - send 1xx informational response before final response
 %% Query params:
 %%   - status: informational status code (default 103)