Fix the pawn unit tests

core/src/coordinates.rs

@@ -1,5 +1,6 @@
 // Eryn Wells <eryn@erynwells.me>
 
+use crate::Color;
 use std::fmt;
 use std::str::FromStr;
 
@@ -168,6 +169,16 @@ impl Rank {
     /// assert_eq!(Rank::PAWN_STARTING_RANKS[Color::Black as usize], Rank::SEVEN);
     /// ```
     pub const PAWN_STARTING_RANKS: [Rank; 2] = [Rank::TWO, Rank::SEVEN];
+
+    pub const PAWN_DOUBLE_PUSH_TARGET_RANKS: [Rank; 2] = [Rank::FOUR, Rank::FIVE];
+
+    pub fn is_pawn_starting_rank(&self, color: Color) -> bool {
+        self == &Self::PAWN_STARTING_RANKS[color as usize]
+    }
+
+    pub fn is_pawn_double_push_target_rank(&self, color: Color) -> bool {
+        self == &Self::PAWN_DOUBLE_PUSH_TARGET_RANKS[color as usize]
+    }
 }
 
 #[rustfmt::skip]