fix code

hutool-core/src/test/java/cn/hutool/core/tree/TreeTest.java

@@ -1,6 +1,7 @@
 package cn.hutool.core.tree;
 
 import cn.hutool.core.collection.ListUtil;
+import cn.hutool.core.lang.Console;
 import org.junit.Assert;
 import org.junit.Test;
 
@@ -77,6 +78,17 @@ public class TreeTest {
 		Assert .assertEquals(7, ids.size());
 	}
 
+	@Test
+	public void walkBroadFirstTest(){
+		final List<String> ids = new ArrayList<>();
+		final Tree<String> tree = TreeUtil.buildSingle(nodeList, "0");
+		Console.log(tree);
+		tree.walk((tr)-> ids.add(tr.getId()), true);
+
+		Console.log(ids);
+		Assert .assertEquals(7, ids.size());
+	}
+
 	@Test
 	public void cloneTreeTest(){
 		final Tree<String> tree = TreeUtil.buildSingle(nodeList, "0");