如何测试从不同频道或控制器对频道进行的广播？

Question

我有一个司机频道，可以将他们的位置广播到供应商频道。

defmodule MyApp.DriverChannel do
    #...

    def handle_in("transmit", payload, socket) do
      MyApp.Endpoint.broadcast! "vendors:lobby", "track", payload
      {:noreply, socket}
    end
end

defmodule MyApp.DriverChannelTest do

  #....

  test "location broadcasts to vendors:lobby", %{socket: socket} do
    push socket, "transmit", %{"hello" => "all"}
    assert_broadcast "track", %{"hello" => "all"}
    # Want something like this
    # assert_broadcast "vendors:lobby", "track", %{"hello" => "all"}
  end

end

这个断言会失败，因为它只检查来自DriverChannel的广播，如何断言对VendorChannel的广播，我查看了源代码，似乎没有传递channel_name的选项到assert_broadcast 宏。

[ 另一个说明] 我也有从控制器发出的广播，如果我知道这个问题的答案，我也可以断言这些广播！ :)

Answer 1

你需要的新版本self

• 订阅：MyApp.Endpoint.subscribe("vendors:lobby")
• 退订：MyApp.Endpoint.unsubscribe("vendors:lobby")

如果您不“取消订阅”，您将收到警告：

[warning] Passing a Pid to Phoenix.PubSub.subscribe is deprecated. Only the calling process may subscribe to topics

新代码：

test "location broadcasts to vendors:lobby", %{socket: socket} do
  MyApp.Endpoint.subscribe("vendors:lobby")
  push socket, "transmit", %{"hello" => "all"}
  assert_broadcast "track", %{"hello" => "all"}
  assert_receive %Phoenix.Socket.Broadcast{
    topic: "vendors:lobby",
    event: "track",
    payload: %{"hello" => "all"}
  MyApp.Endpoint.unsubscribe("vendors:lobby")
end

Answer 2

assert_broadcast只针对订阅的主题，你可以直接通过MyApp.Endpoint.subscribe/2和assert_receive订阅：

test "location broadcasts to vendors:lobby", %{socket: socket} do
  MyApp.Endpoint.subscribe(self, "vendors:lobby")
  push socket, "transmit", %{"hello" => "all"}
  assert_broadcast "track", %{"hello" => "all"}
  assert_receive %Phoenix.Socket.Broadcast{
    topic: "vendors:lobby",
    event: "track",
    payload: %{"hello" => "all"}}
end