Finished step 3: Game

lib/zombie_survivor/game.ex

@@ -0,0 +1,30 @@
+defmodule ZombieSurvivor.Game do
+  alias ZombieSurvivor.{Game, Survivor}
+
+  @type t :: %__MODULE__{survivors: %{String.t() => Survivor.t()}}
+
+  defstruct survivors: %{}
+
+  @spec new() :: Game.t()
+  def new(), do: %Game{}
+
+  @spec add_survivor(Game.t(), Survivor.t()) :: Game.t()
+  def add_survivor(game, survivor) do
+    name = survivor.name
+
+    if Map.has_key?(game, name) do
+      game
+    else
+      %{game | survivors: Map.put(game.survivors, name, survivor)}
+    end
+  end
+
+  @spec ended?(Game.t()) :: boolean
+  def ended?(%Game{survivors: survivors}) when map_size(survivors) == 0, do: false
+
+  def ended?(game) do
+    Enum.all?(game.survivors, fn {_, survivor} ->
+      Survivor.dead?(survivor)
+    end)
+  end
+end

test/game_test.exs

@@ -0,0 +1,72 @@
+defmodule GameTest do
+  use ExUnit.Case
+  alias ZombieSurvivor.{Game, Survivor}
+
+  doctest Game
+
+  @new_survivor Survivor.new(name: "Zombait")
+  @dead_survivor Survivor.new(name: "Deadman", wounds: 2)
+
+  describe "new/0 starts a game" do
+    test "that has 0 survivors" do
+      assert Map.size(Game.new().survivors) == 0
+    end
+  end
+
+  describe "add_survivor/1" do
+    test "adds a survivor to a game" do
+      g =
+        Game.new()
+        |> Game.add_survivor(@new_survivor)
+
+      assert Map.size(g.survivors) == 1
+
+      g =
+        g
+        |> Game.add_survivor(%{@new_survivor | name: "Larry"})
+
+      assert Map.size(g.survivors) == 2
+    end
+
+    test "ensures that two survivors with the same name can't exist" do
+      g =
+        Game.new()
+        |> Game.add_survivor(@new_survivor)
+        |> Game.add_survivor(@new_survivor)
+
+      assert Map.size(g.survivors) == 1
+    end
+  end
+
+  describe "ended?/1" do
+    test "returns true if all its survivors are dead" do
+      # TODO: Property test, add many dead survivors
+      g =
+        Game.new()
+        |> Game.add_survivor(@dead_survivor)
+
+      assert Game.ended?(g)
+
+      g =
+        g
+        |> Game.add_survivor(%{@dead_survivor | name: "Zambee"})
+
+      assert Game.ended?(g)
+    end
+
+    test "returns false if at least one survivor is alive" do
+      g =
+        Game.new()
+        |> Game.add_survivor(@new_survivor)
+        |> Game.add_survivor(@dead_survivor)
+
+      refute Game.ended?(g)
+    end
+
+    test "returns false if no survivors joined" do
+      g = Game.new()
+
+      refute Game.ended?(g)
+    end
+  end
+end