chore: add test for changed fn context

test/components.test.js

@@ -4,6 +4,7 @@ import { mount, defaultOptions, loadVueMetaPlugin } from './utils'
 import GoodbyeWorld from './fixtures/goodbye-world.vue'
 import HelloWorld from './fixtures/hello-world.vue'
 import KeepAlive from './fixtures/keep-alive.vue'
+import Changed from './fixtures/changed.vue'
 
 const getMetaInfo = component => _getMetaInfo(defaultOptions, component)
 
@@ -76,4 +77,21 @@ describe('client', () => {
     const metaInfo = wrapper.vm.$meta().inject()
     expect(metaInfo.title.text()).toEqual('<title data-vue-meta="true">Hello World</title>')
   })
+
+  test('changed function is called', () => {
+    const parentComponent = new Vue({ render: h => h('div') })
+    const wrapper = mount(Changed, { localVue: Vue, parentComponent })
+
+    let context
+    const changed = jest.fn(function() {
+      context = this
+    })
+    wrapper.setData({ changed })
+    wrapper.setData({ childVisible: true })
+
+    wrapper.vm.$parent.$meta().refresh()
+    expect(changed).toHaveBeenCalledTimes(1)
+    // TODO: this isnt what the docs say
+    expect(context._uid).not.toBe(wrapper.vm._uid)
+  })
 })

test/fixtures/changed.vue

@@ -0,0 +1,26 @@
+<template>
+  <div>
+    <hello-world v-if="childVisible"></hello-world>
+  </div>
+</template>
+
+<script>
+import HelloWorld from './hello-world.vue'
+
+export default {
+  components: {
+    HelloWorld
+  },
+  metaInfo() {
+    return {
+      changed: this.changed
+    }
+  },
+  data() {
+    return {
+      childVisible: false,
+      changed: () => {}
+    }
+  }
+}
+</script>