Hi everyone!

TestServer is an easy way to mock third-party services in ExUnit.

Features

• HTTP/1
• HTTP/2
• WebSocket
• TLS with self-signed certificates
• Flexible FIFO match rules
• Catches unexpected requests
• When test finishes verifies there’s no pending routes or websocket handlers to call

Example

test "fetch_url/0" do
  # The test server will autostart the current test server, if not already running
  TestServer.add("/", via: :get)
  TestServer.add("/", via: :get, to: fn conn -> Plug.Conn.send_resp(conn, 200, "second call") end)

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

  assert {:ok, "HTTP"} = MyApp.fetch_url()
  assert {:ok, "second call"} = MyApp.fetch_url()
end

Enabling TLS

TestServer.start(scheme: :https)

The key and certificate is generated with x509 on the fly.

WebSocket Example

test "WebSocketClient" do
  {:ok, socket} = TestServer.websocket_init("/ws")
  :ok = TestServer.websocket_handle(socket, to: fn {:text, "ping"}, state -> {:reply, {:text, "pong"}, state})

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

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

I’ve been using this for testing a JSON RPC endpoint and testing the SSL configuration for http adapters in assent.

I hope you find it useful, feel free to contribute!

https://github.com/danschultzer/test_server