Clean up tests

tests/nba-history.rs

@@ -61,10 +61,10 @@ fn nba_history() {
     let mut model = ks::model::Binary::new(ks::model::binary::Observation::Probit);
 
     for team in teams {
-        let kernel: [Box<dyn ks::Kernel>; 2] = [
-            Box::new(ks::kernel::Constant::new(0.03)),
-            Box::new(ks::kernel::Matern32::new(0.138, 1.753 * seconds_in_year)),
-        ];
+        let kernel = (
+            ks::kernel::Constant::new(0.03),
+            ks::kernel::Matern32::new(0.138, 1.753 * seconds_in_year),
+        );
 
         model.add_item(&team, kernel);
     }