Prevents review app to render an empty dropdown.

When a deployment has no files to show in the dropdown we
fallback to the regular single button for the review app link.

This commit moves the review app link into a component since it's
used twice.

app/assets/javascripts/vue_merge_request_widget/components/deployment.vue

@@ -10,6 +10,7 @@ import { visitUrl } from '../../lib/utils/url_utility';
 import createFlash from '../../flash';
 import MemoryUsage from './memory_usage.vue';
 import StatusIcon from './mr_widget_status_icon.vue';
+import ReviewAppLink from './review_app_link.vue';
 import MRWidgetService from '../services/mr_widget_service';
 
 export default {
@@ -21,6 +22,7 @@ export default {
     Icon,
     TooltipOnTruncate,
     FilteredSearchDropdown,
+    ReviewAppLink,
   },
   directives: {
     tooltip,
@@ -63,6 +65,12 @@ export default {
     deployedText() {
       return this.$options.deployedTextMap[this.deployment.status];
     },
+    shouldRenderDropdown() {
+      return (
+        this.enableCiEnvironmentsStatusChanges &&
+        (this.deployment.changes && this.deployment.changes.length > 0)
+      );
+    },
   },
   methods: {
     stopEnvironment() {
@@ -133,7 +141,7 @@ export default {
           <div>
             <template v-if="hasExternalUrls">
               <filtered-search-dropdown
-                v-if="enableCiEnvironmentsStatusChanges"
+                v-if="shouldRenderDropdown"
                 class="js-mr-wigdet-deployment-dropdown inline"
                 :items="deployment.changes"
                 :main-action-link="deployment.external_url"
@@ -143,18 +151,10 @@ export default {
                   slot="mainAction"
                   slot-scope="slotProps"
                 >
-                  <a
-                    :href="deployment.external_url"
-                    target="_blank"
-                    rel="noopener noreferrer nofollow"
-                    class="deploy-link js-deploy-url inline"
-                    :class="slotProps.className"
-                  >
-                    <span>
-                      {{ __('View app') }}
-                      <icon name="external-link" />
-                    </span>
-                  </a>
+                  <review-app-link
+                    :link="deployment.external_url"
+                    :css-class="`deploy-link js-deploy-url inline ${slotProps.className}`"
+                  />
                 </template>
 
                 <template
@@ -177,18 +177,11 @@ export default {
                   </a>
                 </template>
               </filtered-search-dropdown>
-              <a
+              <review-app-link
                 v-else
-                :href="deployment.external_url"
-                target="_blank"
-                rel="noopener noreferrer nofollow"
-                class="js-deploy-url js-deploy-url-feature-flag deploy-link btn btn-default btn-sm inline"
-              >
-                <span>
-                  {{ __('View app') }}
-                  <icon name="external-link" />
-                </span>
-              </a>
+                :link="deployment.external_url"
+                css-class="js-deploy-url js-deploy-url-feature-flag deploy-link btn btn-default btn-sm inlin"
+              />
             </template>
             <loading-button
               v-if="deployment.stop_url"

app/assets/javascripts/vue_merge_request_widget/components/review_app_link.vue

+<script>
+import Icon from '~/vue_shared/components/icon.vue';
+
+export default {
+  components: {
+    Icon,
+  },
+  props: {
+    link: {
+      type: String,
+      required: true,
+    },
+    cssClass: {
+      type: String,
+      required: true,
+    },
+  },
+};
+</script>
+<template>
+  <a
+    :href="link"
+    target="_blank"
+    rel="noopener noreferrer nofollow"
+    :class="cssClass"
+  >
+    {{ __('View app') }}
+    <icon name="external-link" />
+  </a>
+</template>

changelogs/unreleased/53227-empty-list.yml

+---
+title: Only renders dropdown for review app changes when we have a list of files to
+  show. Otherwise will render the regular review app button
+merge_request:
+author:
+type: other

spec/javascripts/vue_mr_widget/components/deployment_spec.js

@@ -211,6 +211,26 @@ describe('Deployment component', () => {
     });
   });
 
+  describe('without changes', () => {
+    beforeEach(() => {
+      window.gon = window.gon || {};
+      window.gon.features = window.gon.features || {};
+      window.gon.features.ciEnvironmentsStatusChanges = true;
+      delete deploymentMockData.changes;
+
+      vm = mountComponent(Component, { deployment: { ...deploymentMockData } });
+    });
+
+    afterEach(() => {
+      delete window.gon.features.ciEnvironmentsStatusChanges;
+    });
+
+    it('renders the link to the review app without dropdown', () => {
+      expect(vm.$el.querySelector('.js-mr-wigdet-deployment-dropdown')).toBeNull();
+      expect(vm.$el.querySelector('.js-deploy-url-feature-flag')).not.toBeNull();
+    });
+  })
+
   describe('deployment status', () => {
     describe('running', () => {
       beforeEach(() => {

spec/javascripts/vue_mr_widget/components/review_app_link_spec.js

+import Vue from 'vue';
+import component from '~/vue_merge_request_widget/components/review_app_link.vue';
+import mountComponent from '../../helpers/vue_mount_component_helper';
+
+describe('review app link', () => {
+  const Component = Vue.extend(component);
+  const props = {
+    link: '/review',
+    cssClass: 'js-link',
+  };
+  let vm;
+  let el;
+
+  beforeEach(() => {
+    vm = mountComponent(Component, props);
+    el = vm.$el;
+  });
+
+  afterEach(() => {
+    vm.$destroy();
+  });
+
+  it('renders provided link as href attribute', () => {
+    expect(el.getAttribute('href')).toEqual(props.link);
+  });
+
+  it('renders provided cssClass as class attribute', () => {
+    expect(el.getAttribute('class')).toEqual(props.cssClass);
+  });
+
+  it('renders View app text', () => {
+    expect(el.textContent.trim()).toEqual('View app');
+  });
+
+  it('renders svg icon', () => {
+    expect(el.querySelector('svg')).not.toBeNull();
+  });
+});