Add spec for single what's new feature

spec/frontend/whats_new/components/feature_spec.js

+import { shallowMount } from '@vue/test-utils';
+import Feature from '~/whats_new/components/feature.vue';
+
+describe("What's new single feature", () => {
+  /** @type {import("@vue/test-utils").Wrapper} */
+  let wrapper;
+
+  const exampleFeature = {
+    title: 'Compliance pipeline configurations',
+    body:
+      '<p>We are thrilled to announce that it is now possible to define enforceable pipelines that will run for any project assigned a corresponding compliance framework.</p>',
+    stage: 'Manage',
+    'self-managed': true,
+    'gitlab-com': true,
+    packages: ['Ultimate'],
+    url: 'https://docs.gitlab.com/ee/user/project/settings/#compliance-pipeline-configuration',
+    image_url: 'https://img.youtube.com/vi/upLJ_equomw/hqdefault.jpg',
+    published_at: '2021-04-22T00:00:00.000Z',
+    release: '13.11',
+  };
+
+  const findReleaseDate = () => wrapper.find('[data-testid="release-date"]').text();
+
+  const createWrapper = ({ feature } = {}) => {
+    wrapper = shallowMount(Feature, {
+      propsData: { feature },
+    });
+  };
+
+  afterEach(() => {
+    wrapper.destroy();
+    wrapper = null;
+  });
+
+  it('renders the date', () => {
+    createWrapper({ feature: exampleFeature });
+    expect(findReleaseDate()).toBe('April 22, 2021');
+  });
+});