feat(transition): add TransitionGroupStub

Author: eddyerburgh

src/components/TransitionGroupStub.js

@@ -0,0 +1,10 @@
+// @flow
+
+export default {
+  render (h: Function) {
+    const tag: string = this.tag || this.$vnode.data.tag || 'span'
+    const children: Array<VNode> = this.$slots.default || []
+
+    return h(tag, null, children)
+  }
+}

test/resources/components/component-with-transition-group.vue

@@ -0,0 +1,15 @@
+<template>
+  <transition-group>
+    <div>{{a}}</div>
+    <div></div>
+  </transition-group>
+</template>
+
+<script>
+    export default{
+      name: 'component-with-transition',
+      data: () => ({
+        a: 'a'
+      })
+    }
+</script>

test/unit/specs/TransitionGroupStub.spec.js

@@ -0,0 +1,33 @@
+import ComponentWithTransitionGroup from '~resources/components/component-with-transition-group.vue'
+import TransitionGroupStub from '~src/components/TransitionGroupStub'
+import mount from '~src/mount'
+
+describe('TransitionGroupStub', () => {
+  it('update synchronously when used as stubs for Transition', () => {
+    const wrapper = mount(ComponentWithTransitionGroup, {
+      stubs: {
+        'transition-group': TransitionGroupStub
+      }
+    })
+    expect(wrapper.text()).contains('a')
+    wrapper.setData({ a: 'b' })
+    expect(wrapper.text()).contains('b')
+  })
+
+  // it('logs error when has multiple children', () => {
+  //   const TestComponent = {
+  //     template: `
+  //       <transition><div /><div /></transition>
+  //     `
+  //   }
+  //   const msg = '[vue-test-utils]: <transition> can only be used on a single element. Use <transition-group> for lists.'
+  //   const error = sinon.stub(console, 'error')
+  //   mount(TestComponent, {
+  //     stubs: {
+  //       'transition': TransitionStub
+  //     }
+  //   })
+  //   expect(error.args[0][0]).to.equal(msg)
+  //   error.restore()
+  // })
+})