How to test handlers without a socket

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livery_test_adapter:run/3 runs a request you describe in a map through a stack and a handler, and records the response they send. You need it when you want fast unit tests for a handler or a stack, without opening ports, without HTTP clients, without docker.

Run a request through a handler

ok_test() ->
    Cap = livery_test_adapter:run(
        [], fun my_handler:show/1,
        #{method => <<"GET">>, path => <<"/items/1">>,
          bindings => #{<<"id">> => <<"1">>}}),
    ?assertEqual(200, livery_test_adapter:status(Cap)),
    ?assertEqual(<<"application/json">>,
                 livery_test_adapter:header(<<"content-type">>, Cap)).

Build a request spec

The spec map accepts any #livery_req{} field. Defaults: GET on / over h1.

#{
    method   => <<"POST">>,
    path     => <<"/items">>,
    raw_query => <<"draft=true">>,
    headers  => [{<<"content-type">>, <<"application/json">>}],
    bindings => #{<<"id">> => <<"42">>},
    body     => {buffered, <<"{\"name\":\"saw\"}">>},
    peer     => {{127,0,0,1}, 4242}
}

Inspect the response

AccessorReturns
livery_test_adapter:status/1100..599 | undefined
livery_test_adapter:headers/1[{binary(), binary()}]
livery_test_adapter:header/2one header value or undefined
livery_test_adapter:body/1concatenated body as binary()
livery_test_adapter:body_chunks/1individual chunks as [iodata()]
livery_test_adapter:trailers/1trailers or undefined
livery_test_adapter:reset_reason/1reset reason if the stream was aborted
livery_test_adapter:end_stream/1boolean, true after the final frame

Spawn a worker when run/3 is not enough

Start a worker with livery_req_proc when you need what the real per-request worker does: a 500 when the handler crashes, body chunks delivered as messages to its mailbox, several requests running at once.

{ok, Pid} = livery_req_proc:start_link(#{
    adapter => livery_test_adapter,
    stream => Stream,
    req => Req,
    stack => Stack,
    handler => Handler
}),
wait_for_exit(Pid),
Cap = livery_test_adapter:capture(Stream).

See Testing handlers for the four test levels and when to use each.

Drive body messages

A streaming handler receives its body chunks as messages. Send them with the test adapter's helper:

Stream = livery_test_adapter:new_stream(Tab),
Ref = make_ref(),
livery_test_adapter:feed_body(Ref, Pid, {data, <<"chunk">>}),
livery_test_adapter:feed_body(Ref, Pid, eof).

See also