Add a test

Author: TonalidadeHidrica

src/internal_queue.rs

@@ -48,3 +48,57 @@ impl<T> SimpleQueue<T> {
         }
     }
 }
+
+#[cfg(test)]
+mod test {
+    use crate::internal_queue::SimpleQueue;
+
+    #[allow(clippy::cognitive_complexity)]
+    #[test]
+    fn test_simple_queue() {
+        let mut queue = SimpleQueue::default();
+
+        assert_eq!(queue.size(), 0);
+        assert!(queue.empty());
+        assert!(queue.front().is_none());
+        assert!(queue.pop().is_none());
+
+        queue.push(123);
+
+        assert_eq!(queue.size(), 1);
+        assert!(!queue.empty());
+        assert_eq!(queue.front(), Some(&123));
+
+        queue.push(456);
+
+        assert_eq!(queue.size(), 2);
+        assert!(!queue.empty());
+        assert_eq!(queue.front(), Some(&123));
+
+        assert_eq!(queue.pop(), Some(&123));
+        assert_eq!(queue.size(), 1);
+        assert!(!queue.empty());
+        assert_eq!(queue.front(), Some(&456));
+
+        queue.push(789);
+        queue.push(789);
+        queue.push(456);
+        queue.push(456);
+
+        assert_eq!(queue.size(), 5);
+        assert!(!queue.empty());
+        assert_eq!(queue.front(), Some(&456));
+
+        assert_eq!(queue.pop(), Some(&456));
+        assert_eq!(queue.size(), 4);
+        assert!(!queue.empty());
+        assert_eq!(queue.front(), Some(&789));
+
+        queue.clear();
+
+        assert_eq!(queue.size(), 0);
+        assert!(queue.empty());
+        assert!(queue.front().is_none());
+        assert!(queue.pop().is_none());
+    }
+}