deviation: test with empty inputs

Author: munckymagik

src/deviation.rs

@@ -363,4 +363,24 @@ mod tests {
 
         // TODO: gkl_div
     }
+
+    #[test]
+    fn test_deviations_with_empty_inputs() {
+        let a: Array1<f64> = array![];
+
+        assert_eq!(a.count_eq(&a), 0);
+        assert_eq!(a.count_neq(&a), 0);
+        assert_eq!(a.sq_l2_dist(&a), 0.);
+        assert_eq!(a.l2_dist(&a), 0.);
+        assert_eq!(a.l1_dist(&a), 0.);
+        assert_eq!(a.linf_dist(&a), 0.);
+
+        assert!(a.mean_abs_dev(&a).is_nan());
+        assert_eq!(a.max_abs_dev(&a), 0.);
+        assert!(a.mean_sq_dev(&a).is_nan());
+        assert!(a.root_mean_sq_dev(&a).is_nan());
+        assert!(a.peak_signal_to_noise_ratio(&a, 0.).is_nan());
+
+        // TODO: gkl_div
+    }
 }