Acey Ducey (Python): Add unit tests

The unit tests can be executed via:

    $ pip install pytest
    $ pytest .

Also a few more type annotations

01_Acey_Ducey/python/test_acey_ducey_oo.py

@@ -0,0 +1,36 @@
+from acey_ducey_oo import Card, Deck, Game
+
+
+def test_card_init() -> None:
+    card = Card("\u2665", 2)
+    assert card.suit == "\u2665"
+    assert card.rank == 2
+
+
+def test_card_str() -> None:
+    card = Card("\u2665", 2)
+    assert str(card) == "2\u2665"
+
+
+def test_deck_init() -> None:
+    deck = Deck()
+    assert len(deck.cards) == 52
+    assert deck.cards[0].suit == "\u2665"
+    assert deck.cards[0].rank == 2
+
+
+def test_deck_shuffle() -> None:
+    deck = Deck()
+    deck.shuffle()
+
+
+def test_deck_deal() -> None:
+    deck = Deck()
+    card = deck.deal()
+    assert card.rank == 14
+    assert card.suit == "\u2660"
+
+
+def test_game_init() -> None:
+    game = Game()
+    assert len(game.deck.cards) == 50  # two are already dealt