Testing Erlang applications based on cowboy using common test

Question

I have an Erlang application based on Cowboy and I would like to test it.

Previously I used wooga's library etest_http for this kind of tasks, but I would like to start using common tests since I noticed that this is the way used in cowboy. I have tried to setup a very basic test but I am not able to run it properly.

Can anybody provide me a sample for testing the basic example echo_get and tell me what is the correct way to run the test from the console using the Makefile contained in the example?

Answer 1

The example make used only for build echo_get app. So to test echo_get app you can add test suite and call make && rebar -v 1 skip_deps=true ct (rebar should be in PATH) from shell. Also you need etest and etest_http in your Erlang PATH or add it with rebar.config in your application. You can use httpc or curl with os:cmd/1 instead ehttp_test :)

test/my_test_SUITE.erl (full example)

-module(my_test_SUITE).

-compile(export_all).

-include_lib("common_test/include/ct.hrl").

% etest macros
-include_lib ("etest/include/etest.hrl").
% etest_http macros
-include_lib ("etest_http/include/etest_http.hrl").

suite() ->
    [{timetrap,{seconds,30}}].

init_per_suite(Config) ->
    %% start your app or release here
    %% for example start echo_get release
    os:cmd("./_rel/bin/echo_get_example start"),
    Config.

end_per_suite(_Config) ->
    %% stop your app or release here
    %% for example stop echo_get release
    os:cmd("./_rel/bin/echo_get_example stop")
    ok.

init_per_testcase(_TestCase, Config) ->
    Config.

end_per_testcase(_TestCase, _Config) ->
    ok.

all() -> 
    [my_test_case].

my_test_case(_Config) ->
    Response = ?perform_get("http://localhost:8080/?echo=saymyname"),
    ?assert_status(200, Response),
    ?assert_body("saymyname", Response).
    ok.

Answer 2

The following starts the hello_world application and its dependencies, but uses the most recently compiled versions rather than the one in ./_rel; that may or may not be what you want, but it does avoid the timer:sleep(1000)

-module(hello_world_SUITE).
-include_lib("common_test/include/ct.hrl").
-export([all/0, init_per_suite/1, end_per_suite/1]).
-export([http_get_hello_world/1]).

all() ->
    [http_get_hello_world].

init_per_suite(Config) ->
    {ok, App_Start_List} = start([hello_world]),
    inets:start(),
    [{app_start_list, App_Start_List}|Config].

end_per_suite(Config) ->
    inets:stop(),
    stop(?config(app_start_list, Config)),
    Config.

http_get_hello_world(_Config) ->
    {ok, {{_Version, 200, _ReasonPhrase}, _Headers, Body}} =
        httpc:request(get, {"http://localhost:8080", []}, [], []),
    Body = "Hello World!\n".

start(Apps) ->
    {ok, do_start(_To_start = Apps, _Started = [])}.

do_start([], Started) ->
    Started;
do_start([App|Apps], Started) ->
    case application:start(App) of
    ok ->
        do_start(Apps, [App|Started]);
    {error, {not_started, Dep}} ->
        do_start([Dep|[App|Apps]], Started)
    end.

stop(Apps) ->
    _ = [ application:stop(App) || App <- Apps ],
    ok.

Answer 3

Use https://github.com/extend/gun

to run the provided example (considering 'gun' in in 'user' folder): ct_run -suite twitter_SUITE.erl -logdir ./results -pa /home/user/gun/deps/*/ebin /home/user/gun/ebin