# Bookish spork #
Copyright (c) 2018-2019 Alexey Nikitin
__Version:__ 0.2.6
__Authors:__ Alexey Nikitin ([`tank@bohr.su`](mailto:tank@bohr.su)) (_web site:_ [`https://twitter.com/tank_bohr`](https://twitter.com/tank_bohr)).
An erlang library to test http requests. Inspired by Ruby's [WebMock](https://github.com/bblimke/webmock).
Suitable for Elixir.
[
](https://travis-ci.org/tank-bohr/bookish_spork)
[
](https://coveralls.io/github/tank-bohr/bookish_spork?branch=master)
[
](https://hex.pm/packages/bookish_spork)
[
](https://gitter.im/bookish_spork)
### <a name="Rationale">Rationale</a> ###
There are several ways to test your http interaction
* Real http request to real servers: not very reliable, requires internet
* You can use external http server like [`https://httpbin.org/`](https://httpbin.org/) (hackney approach)
* You can mock your http client library
* Also you can run an http-server within your application on your localhost on a particualr port
The last approach is the best IMHO. It is absolutely http-client agnostic. It doesn't require internet connection or any external utilities.
bookish_spork provides you facilities to test your requests with
<strong>real</strong>
http server.
### <a name="Usage">Usage</a> ###
Bookish spork supports Erlang/OTP 20.3 or later.
First step: add to your rebar config
```erlang
{profiles, [
{test, [
{deps, [
{bookish_spork, "0.2.6"}
]}
]}
]}.
```
Second: start server in your tests.
```erlang
bookish_spork:start_server().
```
It starts process without link. Thus you can use it in `init_per_group` and in `init_per_suite` callbacks. Default port is 32002 but you can specify any port you like with `bookish_spork:start_server/1`
#### <a name="Stub_request">Stub request</a> ####
The simplest stub you can do is
```erlang
bookish_spork:stub_request().
```
It will stub your requests with `204 No Content` response with empty body.
If you need specify response you easily can do this:
```erlang
bookish_spork:stub_request(Status, Headers, Content).
```
#### <a name="Capture_request">Capture request</a> ####
As usual the main goal is to test that you send the correct request
```erlang
{ok, Request} = bookish_spork:capture_request().
```
It returns you an opaque structure of the request. You can inspect it with
* [`bookish_spork_request:method/1`](http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_request.md#method-1)
* [`bookish_spork_request:uri/1`](http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_request.md#uri-1)
* [`bookish_spork_request:headers/1`](http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_request.md#headers-1)
* [`bookish_spork_request:body/1`](http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_request.md#body-1)
#### <a name="Bypass_comparision">Bypass comparision</a> ####
An elixir library [bypass](https://github.com/PSPDFKit-labs/bypass) does pretty much the same. And illustrates the same approach. It starts a cowboy web-server to replace a real service for test
But bookish_spork has some advantages:
* Bypass depends on `cowboy` and `plug`. Bookish spork has zero dependencies
* Bookish spork works seamlessly with both erlang and elixir. Bypass is supposed to be an elixir only library
* Bookish spork much simpler
#### <a name="Examples">Examples</a> ####
Setup and teardown
```erlang
init_per_group(_GroupName, Config) ->
{ok, _} = bookish_spork:start_server(),
Config.
end_per_group(_GroupName, _Config) ->
ok = bookish_spork:stop_server().
```
Set expectation
```erlang
init_per_testcase(random_test, Config) ->
bookish_spork:stub_request(200,
<<"{\"value\": \"Chuck Norris' favourite word: chunk.\"}">>),
Config.
```
Make assertions
```erlang
random_test(_Config) ->
?assertEqual(<<"Chuck Norris' favourite word: chunk.">>, testee:make_request()),
{ok, Request} = bookish_spork:capture_request(),
?ssertEqual("/jokes/random", bookish_spork_request:uri(Request)).
```
As you can see there are two types of assertions:
* we check a testee function result
* we check a side effect: verifying outgoing request has correct attributes (uri in this case)
<h5><a name="More_complex_expectations">More complex expectations</a></h5>
There are cases when the testee function initiates more than one request. But if you know the order of your requests, you can set several expectations
```erlang
bookish_spork:stub_request(200, <<"{\"value\": \"The first response\"}">>),
bookish_spork:stub_request(200, <<"{\"value\": \"The second response\"}">>).
```
The library will response in the order the stubs were defined.
Sometimes you can't guarantee the order of requests. Then you may stub request with the fun
```erlang
bookish_spork:stub_request(fun(Request) ->
case bookish_spork_request:uri(Request) of
"/bookish/spork" ->
bookish_spork_response:new(200, <<"Hello">>);
"/admin/sporks" ->
bookish_spork_response:new(403, <<"It is not possible here">>)
end
end)
```
[Module to work with request](http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_request.md)
[Module to work with response](http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_response.md)
<h5><a name="Stub_multiple_requests_with_one_response">Stub multiple requests with one response</a></h5>
It can be usefull to stub several requests with one command
```erlang
bookish_spork:stub_multi([200, #{<<"Content-Type" => "text/plan">>}, <<"Pants">>], _Times = 20)
```
The same with the `fun`
```erlang
bookish_spork:stub_multi(fun(Req) ->
Body = bookish_spork_request:body(Req),
[200, #{<<"X-Respond-With">> => <<"echo">>}, Body]
end, _Times = 150)
```
As you can see that it's not necessary to build response structure yourself. You can use handy [three-element tuple or list syntax](https://github.com/tank-bohr/bookish_spork/issues/32) to define the response. But the [`bookish_spork_response:new/1`](http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_response.md#new-1) still works.
<h5><a name="Elixir_example">Elixir example</a></h5>
```elixir
defmodule ChuckNorrisApiTest do
use ExUnit.Case
doctest ChuckNorrisApi
setup_all do
{:ok, _} = :bookish_spork.start_server
{:ok, %{}}
end
test "retrieves a random joke" do
:bookish_spork.stub_request(200, "{
\"value\": \"Chuck norris tried to crank that soulja boy but it wouldn't crank up\"
}")
assert ChuckNorrisApi.random == "Chuck norris tried to crank that soulja boy but it wouldn't crank up"
{:ok, request} = :bookish_spork.capture_request
assert :bookish_spork_request.uri(request) == '/jokes/random'
end
end
```
For more details see examples dir.
## Modules ##
<table width="100%" border="0" summary="list of modules">
<tr><td><a href="http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork.md" class="module">bookish_spork</a></td></tr>
<tr><td><a href="http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_format.md" class="module">bookish_spork_format</a></td></tr>
<tr><td><a href="http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_request.md" class="module">bookish_spork_request</a></td></tr>
<tr><td><a href="http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_response.md" class="module">bookish_spork_response</a></td></tr>
<tr><td><a href="http://github.com/tank-bohr/bookish_spork/blob/master/doc/bookish_spork_server.md" class="module">bookish_spork_server</a></td></tr></table>
