Moxinet
Mocking server that, just like mox
, allows parallel testing.
Installation
If available in Hex, the package can be installed
by adding moxinet
to your list of dependencies in mix.exs
:
def deps do
[
{:moxinet, "~> 0.1.0"}
]
end
Usage
To use moxinet
you must first define your mock server, from which you'll forward
mock-specific requests:
# test/support/mock_server.ex
defmodule MockServer do
use Moxinet.Server
forward("/github", to: GithubMock)
end
Start moxinet
in test_helper.exs
(before ExUnit.start()
)
{:ok, _} = Moxinet.start()
ExUnit.start()
If you're familiar with plug
, you'll see that our mock server is indeed a plug and can therefore
be extended like one.
After you've added your server, mocks can be defined:
# test/support/mocks/github_mock.ex
defmodule GithubMock do
use Moxinet.Mock
end
In tests, you can create rules for how your mocks should behave through expect/4
:
describe "create_pr/1" do
test "creates a pull request when" do
GithubMock.expect(:post, "/pull-requests/123", fn _payload ->
%{status: 202, body: %{id: "pull-request-id"}}
end)
assert {:ok, %{status: 202, body: %{"id" => "pull-request-id"}}}} = GithubAPI.create_pr(title: "My PR")
end
end
NOTE: One small caveat with moxinet
is that in order for us to be able to match
a mock defined in a request with an incoming request, the requests must send the x-moxinet-ref
header.
Most HTTP libraries allows adding custom headers to your requests, but that might not always be the case.
It's also not recommended to send the x-moxinet-ref
header outside your test environment, meaning you'd
likely want to do find a way to conditionally add it. Here is one example on how to achieve it in req
:
defmodule GithubAPI do
def client do
Req.new([
# ...
])
|> add_moxinet_header()
end
defmacrop add_moxinet_header(req) do
if Mix.env() == :test do
quote do
{header_name, header_value} = Moxinet.build_mock_header()
Req.Request.put_new_header(unquote(req), header_name, header_value)
end
else
quote do
unquote(req)
end
end
end
end
How it works
Moxinet
works a lot similar to mox
except it'll focus on solving the same issue for HTTP request.
The test pid will be registered in the mock registry, where it can later be accessed from inside the mock.
flowchart TD
TP[Test pid] --> MR[Mock registry]
GMS <--> MR
TP --> API[Github API]
API -.HTTP request.-> MS[Mock server]
MS --> GMS[Github Mock]
GMS -.HTTP response.-> API
Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/moxinet.