TestServer

No fuzz ExUnit test server to mock third party services.

Features:

• HTTP/1
• HTTP/2
• WebSocket
• Built-in TLS with self-signed certificates
• Plug route matching

Usage

Add route request expectations with TestServer.add/2:

test "fetch_url/0" do
  # The test server will autostart the current test server, if not already running
  TestServer.add("/", via: :get)

  # The URL is derived from the current test server instance
  Application.put_env(:my_app, :fetch_url, TestServer.url())

  {:ok, "HTTP"} = MyModule.fetch_url()
end

TestServer.add/2 can route a request to an anonymous function or plug with :to option.

TestServer.add("/", to: fn conn ->
  Plug.Conn.send_resp(conn, 200, "OK")
end)

TestServer.add("/", to: MyPlug)

The method listened to can be defined with :via option. By default any method is matched.

TestServer.add("/", via: :post)

A custom match function can be set with :match option:

TestServer.add("/", match: fn
  %{params: %{"a" => "1"}} = _conn -> true
  _conn -> false
end)

When a route is matched it'll be removed from active routes list. The route will be triggered in the order they were added:

TestServer.add("/", via: :get, to: &Plug.Conn.send_resp(&1, 200, "first"))
TestServer.add("/", via: :get, to: &Plug.Conn.send_resp(&1, 200, "second"))

{:ok, "first"} = fetch_request()
{:ok, "second"} = fetch_request()

Plugs can be added to the pipeline with TestServer.plug/1. All plugs will run before any routes are matched. Plug.Conn.fetch_query_params/1 is used if no plugs are set.

TestServer.plug(fn conn ->
  Plug.Conn.fetch_query_params(conn)
end)

TestServer.plug(fn conn ->
  {:ok, body, _conn} = Plug.Conn.read_body(conn, [])

  %{conn | body_params: Jason.decode!(body)}
end)

TestServer.plug(MyPlug)

HTTPS

By default the test server is set up to serve plain HTTP. HTTPS can be enabled with the :scheme option when calling TestServer.start/1.

Custom SSL certificates can also be used by defining the :tls option:

TestServer.start(scheme: :https, tls: [keyfile: key, certfile: cert])

A self-signed certificate suite is automatically generated if you don't set the :tls options:

TestServer.start(scheme: :https)

req_opts = [
  connect_options: [
    transport_opts: [cacerts: TestServer.x509_suite().cacerts],
    protocols: [:http2]
  ]
]

assert {:ok, %Req.Response{status: 200, body: "HTTP/2"}} =
        Req.get(TestServer.url(), req_opts)

WebSocket

WebSocket endpoint can be set up by calling TestServer.websocket_init/2. By default, TestServer.websocket_handle/2 will echo the message received. Messages can be send from the test server with TestServer.websocket_info/2.

test "WebSocketClient" do
  {:ok, socket} = TestServer.websocket_init("/ws")

  :ok = TestServer.websocket_handle(socket)
  :ok = TestServer.websocket_handle(socket, to: fn {:text, "ping"}, state -> {:reply, {:text, "pong"}, state} end)
  :ok = TestServer.websocket_handle(socket, match: fn {:text, message}, _state -> message == "hi")

  {:ok, client} = WebSocketClient.start_link(TestServer.url("/ws"))

  :ok = WebSocketClient.send(client, "hello")
  {:ok, "hello"} = WebSocketClient.receive(client)

  :ok = WebSocketClient.send(client, "ping")
  {:ok, "pong"} = WebSocketClient.receive(client)

  :ok = WebSocketClient.send("hi")
  {:ok, "hi"} = WebSocketClient.receive(client)

  :ok = TestServer.websocket_info(socket, fn state -> {:reply, {:text, "ping"}, state} end)
  {:ok, "ping"} = WebSocketClient.receive(client)
end

Note: WebSocket is not supported by the :httpd adapter.

HTTP Server Adapter

TestServer supports Bandit, Plug.Cowboy, and :httpd out of the box. The HTTP adapter will be selected in this order depending which is available in the dependencies. You can also explicitly set the http server in the configuration when calling TestServer.start/1:

TestServer.start(http_server: {TestServer.HTTPServer.Bandit, []})

You can create your own plug based HTTP Server Adapter by using the TestServer.HTTPServer behaviour.

IPv6

Use the :ipfamily option to test with IPv6 when starting the test server with TestServer.start/1:

TestServer.start(ipfamily: :inet6)

assert :ok =
          TestServer.add("/",
            to: fn conn ->
              assert conn.remote_ip == {0, 0, 0, 0, 0, 65_535, 32_512, 1}

              Plug.Conn.resp(conn, 200, "OK")
            end
          )

Installation

Add test_server to your list of dependencies in mix.exs:

def deps do
  [
    {:test_server, "~> 0.1.20", only: [:test]}
  ]
end

LICENSE

(The MIT License)

Copyright (c) 2022 Dan Schultzer & the Contributors

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.