Define child_spec for Postgrex.Notifications, closes #548

Author: josevalim

Diff for: lib/postgrex/notifications.ex

@@ -84,6 +84,14 @@ defmodule Postgrex.Notifications do
 
   @type server :: GenServer.server()
 
+  @doc false
+  def child_spec(opts) do
+    %{
+      id: __MODULE__,
+      start: {__MODULE__, :start_link, [opts]}
+    }
+  end
+
   @doc """
   Start the notification connection process and connect to postgres.
 

Diff for: test/notification_test.exs

@@ -12,6 +12,10 @@ defmodule NotificationTest do
     {:ok, [pid: pid, pid_ps: pid_ps]}
   end
 
+  test "defines child spec" do
+    start_supervised!({PN, @opts})
+  end
+
   test "fails on sync connection by default" do
     Process.flag(:trap_exit, true)
     assert {:error, _} = PN.start_link(database: "nobody_knows_it")