Added test for draw.

src/lib.rs

@@ -72,7 +72,7 @@ fn draw_margin(p: f64, beta: f64, total_players: f64) -> f64 {
     math::icdf((p + 1.0) / 2.0) * total_players.sqrt() * beta
 }
 
-pub fn rate<R>(rating_groups: &[&[R]]) -> Vec<Rating>
+pub fn rate<R>(rating_groups: &[&[R]], ranks: &[u16]) -> Vec<Rating>
 where
     R: Rateable,
 {
@@ -174,7 +174,7 @@ where
             factor_id,
             ds[i],
             epsilon,
-            false,
+            ranks[i] == ranks[i + 1],
         ));
 
         factor_id += 1;
@@ -342,7 +342,7 @@ mod tests {
     }
 
     #[test]
-    fn test_rate_1vs1() {
+    fn test_rate_4vs4() {
         let alice = Rating::new(MU, SIGMA);
         let bob = Rating::new(MU, SIGMA);
         let chris = Rating::new(MU, SIGMA);
@@ -355,10 +355,28 @@ mod tests {
             Rating::new(16.79337409436942, 6.348053083319977),
         ];
 
-        let ratings = rate(&[&[alice], &[bob], &[chris], &[darren]]);
+        let ratings = rate(&[&[alice], &[bob], &[chris], &[darren]], &[0, 1, 2, 3]);
 
         for (rating, expected) in ratings.iter().zip(expected_ratings.iter()) {
             assert_relative_eq!(rating, expected, epsilon = EPSILON);
         }
     }
+
+    #[test]
+    fn test_rate_1vs1_draw() {
+        let alice = Rating::new(MU, SIGMA);
+        let bob = Rating::new(MU, SIGMA);
+
+        let expected_ratings = vec![
+            Rating::new(25.0, 6.457515683245051),
+            Rating::new(25.0, 6.457515683245051),
+        ];
+
+        let ratings = rate(&[&[alice], &[bob]], &[0, 0]);
+
+        for (rating, expected) in ratings.iter().zip(expected_ratings.iter()) {
+            assert_relative_eq!(rating, expected, epsilon = EPSILON);
+        }
+    }
+
 }