Add extend tests for Deque

Author: rlee287

src/deque.rs

@@ -675,6 +675,31 @@ mod tests {
         assert_eq!(v.back_mut(), None);
     }
 
+    #[test]
+    fn extend() {
+        let mut v: Deque<i32, 4> = Deque::new();
+        v.extend(&[1, 2, 3]);
+        assert_eq!(v.pop_front().unwrap(), 1);
+        assert_eq!(v.pop_front().unwrap(), 2);
+        assert_eq!(*v.front().unwrap(), 3);
+
+        v.push_back(4).unwrap();
+        v.extend(&[5, 6]);
+        assert_eq!(v.pop_front().unwrap(), 3);
+        assert_eq!(v.pop_front().unwrap(), 4);
+        assert_eq!(v.pop_front().unwrap(), 5);
+        assert_eq!(v.pop_front().unwrap(), 6);
+        assert!(v.pop_front().is_none());
+    }
+
+    #[test]
+    #[should_panic]
+    fn extend_panic() {
+        let mut v: Deque<i32, 4> = Deque::new();
+        // Is too many elements -> should panic
+        v.extend(&[1, 2, 3, 4, 5]);
+    }
+
     #[test]
     fn iter() {
         let mut v: Deque<i32, 4> = Deque::new();