ex.ex

# subscription 

 subscription do

    field :new_user, :user do
      config fn _args, _info  ->
        {:ok, topic: "*"}
      end
    end
  end
  
  # publisher 
  def sign_up(_, %{input: params}, _) do
    with {:ok, %User{} = usr} <- Accounts.create_user(params) do

      ApiWeb.Endpoint
      |> Absinthe.Subscription.publish(usr, new_user: "*")

      {:ok, usr}
    end
 end 
 
 # test 
     describe "New User Subscription" do
        @subscription """
            subscription {
                newUser{
                    id
                    username
                }
            }
            """
        @mutation """
            mutation($input: SignUpInput!){
              signup(input: $input) {
                username
              }
            }
            """
        test "broadcasts new user events", %{socket: socket} do


            variables = %{
                "input" => %{
                  "username" => "Zacck Osiemo",
                  "password" => "password"
                }
              }

            # set up a subscription
            ref = push_doc socket, @subscription
            assert_reply ref, :ok, %{subscriptionId: subscription_id}

            # run a mutation
            ref = push_doc socket, @mutation, variables: variables
            assert_reply ref, :ok, reply

            assert %{data: %{"signup" => %{"username" => u_name}}} = reply
        end
    end
end


# test fail 
test New User Subscription broadcasts new user events (ApiWeb.Schema.Subscripion.NewUserTest)
     test/lib/api_web/subscriptions/new_user_test.exs:26
     No message matching %Phoenix.Socket.Reply{ref: ^ref, status: :ok, payload: reply} after 100ms.
     The process mailbox is empty.
     code: assert_reply ref, :ok, reply
     stacktrace:
 test/lib/api_web/subscriptions/new_user_test.exs:43: (test)