Add check to move card to a pile

deck/src/models/card.rs

@@ -22,6 +22,21 @@ impl Card {
     pub fn flip(&mut self) {
         self.is_showed = !self.is_showed;
     }
+
+    pub fn can_place_on_pile(&self, pile: &Vec<Card>) -> bool {
+        let pile_last_card = pile.last();
+        match pile_last_card {
+            Some(card) => (self.rank + 1 == card.rank) && (self.is_red() != card.is_red()),
+            None => self.rank == 13,
+        }
+    }
+
+    pub fn is_red(&self) -> bool {
+        match self.suit {
+            Suit::Hearts | Suit::Diamonds => true,
+            _ => false,
+        }
+    }
 }
 
 impl fmt::Display for Card {
@@ -45,6 +60,7 @@ impl fmt::Display for Card {
         }
     }
 }
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -76,4 +92,64 @@ mod tests {
         card.flip();
         assert_eq!(card.is_showed, true);
     }
+
+    #[test]
+    fn check_that_card_red() {
+        let must_be_red = Card::new(10, Suit::Hearts);
+        assert!(must_be_red.is_red());
+        let must_be_red = Card::new(1, Suit::Diamonds);
+        assert!(must_be_red.is_red());
+        let must_be_black = Card::new(10, Suit::Clubs);
+        assert_eq!(false, must_be_black.is_red());
+        let must_be_black = Card::new(1, Suit::Spades);
+        assert_eq!(false, must_be_black.is_red());
+    }
+
+    #[test]
+    fn can_place_on_pile() {
+        let card_to_check = Card::new(3, Suit::Hearts);
+        let pile = vec![Card::new(4, Suit::Spades)];
+
+        assert!(card_to_check.can_place_on_pile(&pile));
+    }
+
+    #[test]
+    fn cant_be_placed_on_pile_because_rank() {
+        let card_to_check = Card::new(13, Suit::Hearts);
+        let pile = vec![Card::new(11, Suit::Spades)];
+
+        let can_place = card_to_check.can_place_on_pile(&pile);
+
+        assert_eq!(false, can_place);
+    }
+
+    #[test]
+    fn cant_be_placed_on_pile_because_color() {
+        let card_to_check = Card::new(2, Suit::Spades);
+        let pile = vec![Card::new(3, Suit::Clubs)];
+
+        let can_place = card_to_check.can_place_on_pile(&pile);
+
+        assert_eq!(false, can_place);
+    }
+
+    #[test]
+    fn can_be_placed_on_empty_pile() {
+        let card_to_check = Card::new(13, Suit::Clubs);
+        let pile: Vec<Card> = vec![];
+
+        let can_be_placed = card_to_check.can_place_on_pile(&pile);
+
+        assert!(can_be_placed);
+    }
+
+    #[test]
+    fn cant_be_placed_on_empty_pile() {
+        let card_to_check = Card::new(12, Suit::Hearts);
+        let pile: Vec<Card> = vec![];
+
+        let can_be_placed = card_to_check.can_place_on_pile(&pile);
+
+        assert_eq!(false, can_be_placed);
+    }
 }