Add shape method to Matrix and corresponding unit test

src/matrix/mat.rs

@@ -89,6 +89,10 @@ impl<T: Clone> Matrix<T> {
         self.cols
     }
 
+    pub fn shape(&self) -> (usize, usize) {
+        (self.rows, self.cols)
+    }
+
     /// Get element reference (immutable). Panics on out-of-bounds.
     pub fn get(&self, r: usize, c: usize) -> &T {
         &self[(r, c)]
@@ -1153,6 +1157,14 @@ mod tests {
         assert_eq!(ma.row(2), &[3, 6, 9]);
     }
 
+    #[test]
+    fn test_shape(){
+        let ma = static_test_matrix_2x4();
+        assert_eq!(ma.shape(), (2, 4));
+        assert_eq!(ma.rows(), 2);
+        assert_eq!(ma.cols(), 4);
+    }
+
     #[test]
     #[should_panic(expected = "row index 3 out of bounds for 3 rows")]
     fn test_row_out_of_bounds() {