Test event conversion

lib/midi_player.ex

@@ -5,6 +5,8 @@ defmodule MIDIPlayer do
   A GenServer for playing a schedule of MIDI commands at predefined times.
   """
 
+  @type schedule :: [{non_neg_integer(), binary()}]
+
   # Client API
 
   @doc """
@@ -66,11 +68,23 @@ defmodule MIDIPlayer do
   @doc """
   Resume playback on the player after it has been paused.
   """
-  @spec(resume() :: :ok, {:error, :not_paused})
+  @spec resume() :: :ok | {:error, :not_paused}
   def resume do
     GenServer.call(__MODULE__, :resume)
   end
 
+  @doc """
+  Get the current schedule of the player.
+
+  The schedule is a list of tuples of a time in milliseconds and the
+  corresponding bitstream of MIDI commands to be played at that time.
+  The list is guaranteed to be ascending in time.
+  """
+  @spec get_schedule() :: schedule()
+  def get_schedule do
+    GenServer.call(__MODULE__, :get_schedule)
+  end
+
   # Server callbacks
 
   @impl GenServer
@@ -142,6 +156,10 @@ defmodule MIDIPlayer do
     {:reply, :ok, %{state | timer: timer, start_time: start_time, pause_time: nil}}
   end
 
+  def handle_call(:get_schedule, _from, %{schedule: schedule} = state) do
+    {:reply, schedule, state}
+  end
+
   @impl GenServer
   def handle_info(
         :play,

test/player_test.exs

@@ -39,4 +39,20 @@ defmodule MIDIPlayerTest do
     Player.pause()
     assert {:error, :already_paused} = Player.pause()
   end
+
+  test "event conversion" do
+    event1 = MIDIPlayer.Event.ChangeProgram.new(0, 1, 40)
+    event2 = MIDIPlayer.Event.Note.new(0, 60, 1, 1000, 127)
+    events = [event1, event2]
+    duration = 100
+    assert :ok = Player.generate_schedule(events, duration)
+
+    change_program = MIDISynth.Command.change_program(0, 40)
+    note_on = MIDISynth.Command.note_on(0, 60, 127)
+    note_off = MIDISynth.Command.note_off(0, 60)
+
+    [command1, command2] = Player.get_schedule()
+    assert {1, <<^change_program::binary-size(2), ^note_on::binary-size(3)>>} = command1
+    assert {1000, ^note_off} = command2
+  end
 end