add simple directive and test

src/__tests__/components/CompWithDirective.vue

@@ -0,0 +1,14 @@
+<template>
+  <input v-value="value" />
+</template>
+
+<script>
+export default {
+  props: {
+    value: {
+      type: String,
+      required: true,
+    },
+  },
+}
+</script>

src/__tests__/components/directives/v-value.js

@@ -0,0 +1,3 @@
+export function value(el, binding) {
+  el.value = binding.value
+}

src/__tests__/use-global-directive.js

@@ -0,0 +1,18 @@
+import '@testing-library/jest-dom/extend-expect'
+import {render, wait} from '@testing-library/vue'
+import {value as valueDirective} from './components/directives/v-value'
+import CompWithDirective from './components/CompWithDirective.vue'
+
+test('element should have the same value as the directive', async () => {
+  const value = 'test'
+  const {container, updateProps} = render(
+    CompWithDirective,
+    {props: {value}},
+    vue => vue.directive('value', valueDirective),
+  )
+  await wait()
+  expect(container.firstChild).toHaveValue(value)
+  const anotherValue = 'another'
+  await updateProps({value: anotherValue})
+  expect(container.firstChild).toHaveValue(anotherValue)
+})