add cache tests

test/chesstrainer/cache_test.exs

@@ -0,0 +1,39 @@
+defmodule Chesstrainer.CacheTest do
+  use ExUnit.Case, async: true
+
+  alias Chesstrainer.Cache
+
+  setup do
+    table = :"test_#{System.unique_integer([:positive])}"
+    {:ok, pid} = Cache.start_link(table)
+    on_exit(fn -> if Process.alive?(pid), do: GenServer.stop(pid) end)
+    {:ok, %{pid: pid, table: table}}
+  end
+
+  describe "ChessTrainer.Cache function tests" do
+    test "cache is started", %{pid: pid, table: table} do
+      assert is_pid(pid)
+      assert 0 = Cache.size(table)
+    end
+
+    test "put/3", %{table: table} do
+      assert :ok = Cache.put(table, "key1", "value1")
+      assert {:ok, "value1"} = Cache.get(table, "key1")
+      assert 1 = Cache.size(table)
+
+      assert :ok = Cache.put(table, "key2", "value2")
+      assert {:ok, "value2"} = Cache.get(table, "key2")
+      assert 2 = Cache.size(table)
+    end
+
+    test "delete/2", %{table: table} do
+      assert :ok = Cache.put(table, "key1", "value1")
+      assert :ok = Cache.put(table, "key2", "value2")
+      assert 2 = Cache.size(table)
+
+      assert :ok = Cache.delete(table, "key1")
+      assert 1 = Cache.size(table)
+      assert :error = Cache.get(table, "key1")
+    end
+  end
+end