修改add方法，并添加测试类

byhieg · byhieg · commit f803b81486fb · 2017-02-15T14:21:12.000+08:00
diff --git a/src/main/java/cn/byhieg/collectiontutorial/listtutorial/SimpleLinkedList.java b/src/main/java/cn/byhieg/collectiontutorial/listtutorial/SimpleLinkedList.java
@@ -22,7 +22,7 @@ public boolean add(E element) {
 
     private void addAtLast(E element) {
         Node<E> l = last;
-        Node<E> node = new Node<E>(element, null, l);
+        Node<E> node = new Node<>(element, null, l);
         last = node;
         if (l == null) {
             first = node;
@@ -46,7 +46,7 @@ private void addBeforeNode(E element, Node<E> specifiedNode) {
         Node<E> preNode = specifiedNode.prev;
         Node<E> newNode = new Node<>(element, specifiedNode, preNode);
         if (preNode == null) {
-            first.next = newNode;
+            first = newNode;
         } else {
             preNode.next = newNode;
         }
diff --git a/src/test/java/cn/byhieg/collectiontutorialtest/SimpleLinkedListTest.java b/src/test/java/cn/byhieg/collectiontutorialtest/SimpleLinkedListTest.java
@@ -0,0 +1,19 @@
+package cn.byhieg.collectiontutorialtest;
+
+import cn.byhieg.collectiontutorial.listtutorial.SimpleArrayList;
+import junit.framework.TestCase;
+
+/**
+ * Created by byhieg on 17/2/15.
+ * Mail to byhieg@gmail.com
+ */
+public class SimpleLinkedListTest extends TestCase {
+    public void testAdd() throws Exception {
+        new SimpleArrayList().add(11111);
+    }
+
+    public void testAdd1() throws Exception {
+        new SimpleArrayList().add(0,10);
+    }
+
+}
