refact test

Author: douchuan

src/sort/heap.rs

@@ -11,7 +11,7 @@ where
 {
     let data = Vec::from(a);
     let mut heap = BinaryHeap::new(data, test);
-    let mut res = Vec::new();
+    let mut res = Vec::with_capacity(a.len());
     while let Some(v) = heap.pop() {
         res.push(v);
     }

src/sort/tree_selection.rs

@@ -45,10 +45,7 @@ fn pop<T: Copy + std::cmp::Ord + Minimal>(tree: &mut Tree<T>) -> Option<T> {
 }
 
 // 返回叶子节点的序号
-fn replace_max_by_min<T: Copy + std::cmp::Ord + Minimal>(
-    tree: &mut Tree<T>,
-    root_key: T,
-) -> usize {
+fn replace_max_by_min<T: Copy + std::cmp::Ord + Minimal>(tree: &mut Tree<T>, root_key: T) -> usize {
     let mut idx = tree.root.unwrap();
     tree.node_at_mut(idx).unwrap().key = T::minimal();
 

tests/test_binary_tree.rs

@@ -32,50 +32,25 @@ fn t_empty_tree() {
     let tree = new_tree(&["#"]);
     assert!(tree.arena.is_empty());
     assert!(tree.root.is_none());
+
+    let r = PreOrderVisitor::iterate(&tree);
+    assert!(r.is_empty());
 }
 
 #[test]
 fn t_tree_topology1() {
     let tokens = vec!["1", "#", "2", "3"];
     let tree = new_tree(&tokens);
-    let p0 = tree.root.expect("invalid p0");
-    let p0 = tree.node_at(p0).expect("invalid p0 node");
-    assert_eq!(p0.key, 1);
-    assert!(p0.left.is_none());
-    //p1: '#'
-    let p2 = p0.right.expect("invalid p0 right");
-    let p2 = tree.node_at(p2).expect("invalid p2 node");
-    assert_eq!(p2.key, 2);
-    assert!(p2.right.is_none());
-    let p3 = p2.left.expect("invalid p2 left");
-    let p3 = tree.node_at(p3).expect("invalid p3 node");
-    assert_eq!(p3.key, 3);
+    let r = PreOrderVisitor::iterate(&tree);
+    assert_eq!(r, vec![1, 2, 3]);
 }
 
 #[test]
 fn t_tree_topology2() {
     let tokens = vec!["1", "2", "#", "3", "4", "#", "#", "5"];
     let tree = new_tree(&tokens);
-    let p0 = tree.root.expect("invalid p0");
-    let p0 = tree.node_at(p0).expect("invalid p0 node");
-    assert_eq!(p0.key, 1);
-    assert!(p0.right.is_none());
-    let p1 = p0.left.expect("invalid p0 left");
-    let p1 = tree.node_at(p1).expect("invalid p1 node");
-    assert_eq!(p1.key, 2);
-    //p2: '#'
-    let p3 = p1.left.expect("invalid p3");
-    let p3 = tree.node_at(p3).expect("invalid p3 node");
-    assert_eq!(p3.key, 3);
-    let p4 = p1.right.expect("invalid p4");
-    let p4 = tree.node_at(p4).expect("invalid p3 node");
-    assert_eq!(p4.key, 4);
-    //p5: '#'
-    //p6: '#'
-    let p7 = p3.left.expect("invalid p7");
-    let p7 = tree.node_at(p7).expect("invalid p7 node");
-    assert_eq!(p7.key, 5);
-    assert_eq!(tree.arena.len(), 5);
+    let r = PreOrderVisitor::iterate(&tree);
+    assert_eq!(r, vec![1, 2, 3, 5, 4]);
 }
 
 #[test]