Get the ball rolling on writing tests

Separate loading story file and starting state server.
Add test for op_add

lib/xyzzy/machine/state.ex

@@ -9,9 +9,9 @@ defmodule Xyzzy.Machine.State do
             static_mem: 0,
             high_mem: 0,
             dictionary: 0,
-            object_table: %{},
+            object_table: 0,
             abbr_table: 0,
-            global_vars: %{},
+            global_vars: 0,
             flags1: 0,
             flags2: 0
 end

lib/xyzzy/machine/state/server.ex

@@ -73,8 +73,7 @@ defmodule Xyzzy.Machine.State.Server do
 
   def init(story) do
     :rand.seed(:exsplus, :os.timestamp)
-    state = Xyzzy.Machine.open_story(story)
-    {:ok, state}
+    {:ok, story}
   end
 
   def handle_call(:pop_stack, _from, state = %State{stack: [h|t]}) do

mix.exs

@@ -27,6 +27,6 @@ defmodule Xyzzy.Mixfile do
   #
   # Type "mix help deps" for more examples and options
   defp deps do
-    [{:credo, "~> 0.4", only: [:dev, :test]}]
+    []
   end
 end

test/opcode_test.exs

@@ -0,0 +1,30 @@
+defmodule OpcodeTest do
+  alias Xyzzy.Machine.OpFuncs
+  alias Xyzzy.Machine.OpInfo
+  alias Xyzzy.Machine.State
+
+  use ExUnit.Case
+  doctest Xyzzy
+
+  setup do
+    {:ok, _pid} = State.Registry.start_link
+    {:ok, _pid} = State.Supervisor.start_link
+    :ok
+  end
+
+  test "op_add" do
+    info = %OpInfo{operands: [2, 2],
+                   next_pc: 0xBEEF,
+                   return_store: 0x02}
+
+    state = %State{locals: %{2 => 0}}
+    State.Supervisor.start_game(state, "op_add_test")
+
+    OpFuncs.op_add("op_add_test", info)
+
+    state = State.Server.get_state("op_add_test")
+
+    assert state.pc == 0xBEEF
+    assert state.locals |> Map.get(2) == 4
+  end
+end