[Improvement] Rebuild test system (#1051)

packages/list/test/__snapshots__/index.spec.js.snap

@@ -0,0 +1,22 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`renders list correctly 1`] = `
+<div>
+  <div>
+    <p class="page-desc">当即将滚动到元素底部时，会自动加载更多</p>
+    <div class="van-pull-refresh">
+      <div class="van-pull-refresh__track" style="transition:0ms;transform:translate3d(0,0px, 0);">
+        <div class="van-pull-refresh__head">
+          <!---->
+          <!---->
+          <!---->
+        </div>
+        <div class="van-list">
+          <div class="van-list__loading" style="display:none;">
+            <div class="van-loading van-loading--circular van-loading--black"><span class="van-loading__spinner van-loading__spinner--circular"> <svg viewBox="25 25 50 50" class="van-loading__circular"><circle cx="50" cy="50" r="20" fill="none"></circle></svg></span></div> <span class="van-list__loading-text">加载中...</span></div>
+        </div>
+      </div>
+    </div>
+  </div>
+</div>
+`;

packages/list/test/index.spec.js

@@ -0,0 +1,4 @@
+import List from '../';
+import demoTest from '../../../test/demo-test';
+
+demoTest(List);