initial tests added

config/config.exs

@@ -58,6 +58,8 @@ config :logger, :console,
 # Use Jason for JSON parsing in Phoenix
 config :phoenix, :json_library, Jason
 
+config :live_beats, :presence_client, LiveBeats.PresenceClient
+
 # Import environment specific config. This must remain at the bottom
 # of this file so it overrides the configuration defined above.
 import_config "#{config_env()}.exs"

config/test.exs

@@ -31,3 +31,5 @@ config :logger, level: :warn
 
 # Initialize plugs at runtime for faster test compilation
 config :phoenix, :plug_init_mode, :runtime
+
+config :live_beats, :presence_client, Phoenix.Presence.Client.Mock

lib/live_beats/application.ex

@@ -23,7 +23,7 @@ defmodule LiveBeats.Application do
       LiveBeatsWeb.Endpoint,
       # Start a worker by calling: LiveBeats.Worker.start_link(arg)
       # {LiveBeats.Worker, arg}
-      {Phoenix.Presence.Client, client: LiveBeats.PresenceClient, pubsub: LiveBeats.PubSub, presence: LiveBeatsWeb.Presence}
+      {Phoenix.Presence.Client, client: Application.get_env(:live_beats, :presence_client), pubsub: LiveBeats.PubSub, presence: LiveBeatsWeb.Presence}
     ]
 
     # See https://hexdocs.pm/elixir/Supervisor.html

lib/live_beats/presence/phoenix_presence_client.ex

@@ -42,8 +42,7 @@ defmodule Phoenix.Presence.Client do
   end
 
   def handle_call(:state, _from, state) do
-    IO.inspect(state.topics, label: :state_topics)
-    {:reply, :ok, state}
+    {:reply, state, state}
   end
 
   def handle_call({:track, pid, topic, key, meta}, _from, state) do

test/live_beats/presence/presence_client_test.exs

@@ -0,0 +1,49 @@
+defmodule Phoenix.Presence.ClientTest do
+  use ExUnit.Case, async: true
+
+  alias Phoenix.Presence.Client.PresenceMock
+
+  test "When a new process is tracked, a topic is created" do
+    presence_key = 1
+    topic_id = 100
+
+    {:ok, pid} = PresenceMock.start_link(id: presence_key)
+
+    PresenceMock.track(pid, topic(topic_id), presence_key)
+    assert Process.alive?(pid)
+    # _ = :sys.get_state(PresenceClient)
+    :timer.sleep(1000)# not the best
+
+    assert %{topics: %{"mock_topic:100" => %{"1" => [%{phx_ref: _ref}]}}} =
+             GenServer.call(PresenceClient, :state)
+
+    send(pid, :quit)
+    :timer.sleep(1000)
+    refute Process.alive?(pid)
+  end
+
+  test "topic is removed from the topics state when there is no more presences" do
+    presence_key = 1
+    topic_id = 100
+
+    {:ok, pid} = PresenceMock.start_link(id: presence_key)
+
+    PresenceMock.track(pid, topic(topic_id), presence_key)
+    assert Process.alive?(pid)
+    # _ = :sys.get_state(PresenceClient)
+
+    :timer.sleep(1000)# not the best
+
+    assert %{topics: %{"mock_topic:100" => %{"1" => [%{phx_ref: _ref}]}}} =
+             GenServer.call(PresenceClient, :state)
+
+    send(pid, :quit)
+    :timer.sleep(1000)
+    refute Process.alive?(pid)
+    assert %{topics: %{}} = GenServer.call(PresenceClient, :state)
+  end
+
+  defp topic(id) do
+    "mock_topic:#{id}"
+  end
+end

test/support/presence/client_mock.ex

@@ -0,0 +1,17 @@
+defmodule Phoenix.Presence.Client.Mock do
+
+  def init(_opts) do
+    {:ok, %{}}
+  end
+
+  def handle_join(_topic, _key, _meta, state) do
+    IO.inspect(:handle_join)
+    {:ok, state}
+  end
+
+  def handle_leave(_topic, _key, _meta, state) do
+    IO.inspect(:handle_leave)
+    {:ok, state}
+  end
+
+end

test/support/presence/presence_mock.ex

@@ -0,0 +1,31 @@
+defmodule Phoenix.Presence.Client.PresenceMock do
+
+  use GenServer
+  alias Phoenix.Presence.Client
+
+
+  def start_link(opts \\ []) do
+    GenServer.start_link(__MODULE__, opts[:id], opts)
+  end
+
+  @impl true
+  def init(id) do
+    {:ok, %{id: id}}
+  end
+
+  def track(pid, topic, key) do
+    GenServer.cast(pid, {:track, topic, key})
+  end
+
+  @impl true
+  def handle_info(:quit, state) do
+    IO.inspect(:quit)
+    {:stop, :normal, state}
+  end
+
+  @impl true
+  def handle_cast({:track, topic, key}, state) do
+    Client.track(topic, key, %{})
+    {:noreply, state}
+  end
+end