如何在phoenix.socket.broadcast有效载荷中测试或序列化结构

Question

如何在通道测试中自动将eTecto struct序列化与JSON响应？正如我在文档The event’s message must be a serializable map中看到的那样，我在答案和教程中发现，当我在模型中使用Poison.Encoder时，则应编码通过传输（据我所知）传递的任何消息。

示例模型：

use PhoenixTrello.Web, :model
  # ...
  @derive {Poison.Encoder, only: [:id, :first_name, :last_name, :email]}
  # ...
end

从频道功能之一广播：

broadcast_from! socket, "card:created", %{card: card}

最终尝试从测试中的广播中接收有效载荷：

assert_receive %Phoenix.Socket.Broadcast{topic: ^t1, event: "card:created", payload: ^payload}

然后，它上升不匹配错误，而在有效载荷中未序列化结构（我试图匹配派生的模型filelds）：

Process mailbox:
  %Phoenix.Socket.Broadcast{event: "card:created", payload: %{card: %PhoenixTrello.Card{__meta__: #Ecto.Schema.Metadata<:loaded, "cards">, ... user: #Ecto.Association.NotLoaded<association :user is not loaded>, user_id: 1833}}, topic: "boards:1833"}

如何在测试中获取序列化的JSON消息，就好像是客户端应用吗？

Answer 1

我会首先assert_receive原始消息，然后进行Poison.encode!，然后进行第二个assert：

payload = "{"card": ...}"
assert_receive %Phoenix.Socket.Broadcast{topic: ^t1, event: "card:created", payload: raw_payload}
assert Poison.encode!(raw_payload) == payload