     end
   end
 
-  describe ".step_back" do
+  describe "GameServer.step_back/1" do
     test "does nothing when the history is empty" do
       assert GameServer.step_back(@empty_state) == @empty_state
     end

    end
  end

  describe ".handle_call :pause" do
    test "suspend's running games" do
      assert(GameServer.handle_call(:pause, self(), @cont_state) ==
       {:reply, :ok, @suspend_state})

    end
  end

  describe "GameServer.handle_call(:next, _, _)" do
    test "executes the reducer once if the game is not ended" do
      state = %State{world: 1, reducer: &(&1+1)}

