test: panic test for invalid pdf argument

Author: henryjac

src/distribution/multivariate_normal.rs

@@ -373,4 +373,11 @@ mod tests  {
         test_case(vec![0., 0.], vec![f64::INFINITY, 0., 0., f64::INFINITY], f64::NEG_INFINITY, ln_pdf(dvec![10., 10.]));
         test_case(vec![0., 0.], vec![f64::INFINITY, 0., 0., f64::INFINITY], f64::NEG_INFINITY, ln_pdf(dvec![100., 100.]));
     }
+
+    #[test]
+    #[should_panic]
+    fn test_pdf_mismatched_arg_size() {
+        let mvn = MultivariateNormal::new(vec![0., 0.], vec![1., 0., 0., 1.,]).unwrap();
+        mvn.pdf(&dvec![1.]); // x.size != mu.size
+    }
 }

src/distribution/multivariate_students_t.rs

@@ -449,4 +449,11 @@ mod tests  {
         test_almost_multivariate_normal(vec![0., 0.,], vec![1., 0., 0., 1.], 1e10, 1e-5, dvec![1., 1.], pdf_mvs, pdf_mvn);
         test_almost_multivariate_normal(vec![0., 0.,], vec![1., 0., 0., 1.], f64::INFINITY, 1e-50, dvec![1., 1.], pdf_mvs, pdf_mvn);
     }
+
+    #[test]
+    #[should_panic]
+    fn test_pdf_mismatched_arg_size() {
+        let mvs = MultivariateStudent::new(vec![0., 0.], vec![1., 0., 0., 1.,], 3.).unwrap();
+        mvs.pdf(&dvec![1.]); // x.size != mu.size
+    }
 }