[Improvement] Dialog: optimize style without content (#1233)

packages/dialog/test/__snapshots__/demo.spec.js.snap

@@ -17,7 +17,7 @@ exports[`renders demo correctly 1`] = `
       <!----><span class="van-button__text">高级用法</span></button>
     <div class="van-dialog" style="display:none;">
       <!---->
-      <div class="van-hairline van-dialog__content">
+      <div class="van-dialog__content">
         <div placeholder="请输入用户名" class="van-cell van-hairline van-field">
           <!---->
           <div class="van-cell__title"><span>用户名</span>
@@ -45,7 +45,7 @@ exports[`renders demo correctly 1`] = `
           <!---->
         </div>
       </div>
-      <div class="van-dialog__footer van-dialog__footer--buttons">
+      <div class="van-hairline--top van-dialog__footer van-dialog__footer--buttons">
         <button class="van-button van-button--default van-button--large van-dialog__cancel">
           <!----><span class="van-button__text">
         取消

packages/dialog/test/index.spec.js

@@ -0,0 +1,63 @@
+import Vue from 'vue';
+import Dialog from '..';
+import DialogVue from '../dialog';
+import { mount } from '@vue/test-utils';
+import { later, transitionStub } from '../../../test/utils';
+
+transitionStub();
+
+test('Dialog function call', async() => {
+  Dialog.close();
+  Dialog.alert('1');
+
+  const callback = jest.fn();
+  const dialog = document.querySelector('.van-dialog');
+
+  await later();
+  expect(dialog.style.display).toEqual('');
+  Dialog.close();
+
+  await later();
+  expect(dialog.style.display).toEqual('none');
+  Dialog.confirm().catch(callback);
+  document.querySelector('.van-dialog__cancel').click();
+
+  await later();
+  expect(callback.mock.calls[0][0]).toEqual('cancel');
+  Dialog.confirm().then(callback);
+  document.querySelector('.van-dialog__confirm').click();
+
+  await later();
+  expect(callback.mock.calls[1][0]).toEqual('confirm');
+});
+
+test('before close', () => {
+  const wrapper = mount(DialogVue, {
+    propsData: {
+      beforeClose: (action, done) => done(false)
+    }
+  });
+
+  const cancel = wrapper.find('.van-dialog__cancel');
+
+  cancel.trigger('click');
+  expect(wrapper.emitted('cancel')).toBeFalsy();
+
+  wrapper.setProps({
+    beforeClose: (action, done) => done()
+  });
+  cancel.trigger('click');
+  expect(wrapper.emitted('cancel')).toBeTruthy();
+});
+
+test('set default options', () => {
+  Dialog.setDefaultOptions({ lockScroll: false });
+  expect(Dialog.currentOptions.lockScroll).toBeFalsy();
+  Dialog.resetDefaultOptions();
+  expect(Dialog.currentOptions.lockScroll).toBeTruthy();
+});
+
+test('register component', () => {
+  Vue.use(Dialog);
+  expect(Vue.component(DialogVue.name)).toBeTruthy();
+});