Add tests for socket drainer configuration

test/phoenix/socket/socket_test.exs

@@ -81,4 +81,49 @@ defmodule Phoenix.SocketTest do
       assert socket.assigns[:abc] == :def
     end
   end
+
+  describe "drainer_spec/1" do
+    defmodule Endpoint do
+      use Phoenix.Endpoint, otp_app: :phoenix
+    end
+
+    defmodule DrainerSpecSocket do
+      use Phoenix.Socket
+
+      def id(_), do: "123"
+
+      def dynamic_drainer_config do
+        [
+          batch_size: 200,
+          batch_interval: 2_000,
+          shutdown: 20_000
+        ]
+      end
+    end
+
+    test "loads static drainer config" do
+      drainer_spec = [
+        batch_size: 100,
+        batch_interval: 1_000,
+        shutdown: 10_000
+      ]
+
+      assert DrainerSpecSocket.drainer_spec(drainer: drainer_spec, endpoint: Endpoint) ==
+               {Phoenix.Socket.PoolDrainer, {Endpoint, DrainerSpecSocket, drainer_spec}}
+    end
+
+    test "loads dynamic drainer config" do
+      drainer_spec = DrainerSpecSocket.dynamic_drainer_config()
+
+      assert DrainerSpecSocket.drainer_spec(
+               drainer: {DrainerSpecSocket, :dynamic_drainer_config, []},
+               endpoint: Endpoint
+             ) ==
+               {Phoenix.Socket.PoolDrainer, {Endpoint, DrainerSpecSocket, drainer_spec}}
+    end
+
+    test "returns ignore if drainer is set to false" do
+      assert DrainerSpecSocket.drainer_spec(drainer: false, endpoint: Endpoint) == :ignore
+    end
+  end
 end