remove unused discard

src/game/rule/operation/phase_test.go

@@ -150,18 +150,14 @@ func TestDeal(t *testing.T) {
 
 func newDeck() entity.Deck {
 	deck := make([]entity.Card, 0, 26)
-	discard := make([]entity.Card, 0, 26)
 	for i := 0; i < 52; i++ {
 		card := entity.Card{Suit: i % 4, Value: i % 13}
 		if i%2 == 1 {
 			deck = append(deck, card)
-		} else {
-			discard = append(discard, card)
 		}
 	}
 	return entity.Deck{
-		Deck:    deck,
-		Discard: discard,
+		Deck: deck,
 	}
 }