Fix moderation interface when missing album cover

changes/changelog.d/1474.bugfix

+Fixes crash in album moderation interface when missing cover (#1474)

front/src/views/admin/library/AlbumDetail.vue

@@ -9,7 +9,7 @@
           <div class="ui column">
             <div class="segment-content">
               <h2 class="ui header">
-                <img alt="" v-if="object.cover.urls.original" v-lazy="$store.getters['instance/absoluteUrl'](object.cover.urls.medium_square_crop)">
+                <img alt="" v-if="object.cover && object.cover.urls.original" v-lazy="$store.getters['instance/absoluteUrl'](object.cover.urls.medium_square_crop)">
                 <img alt="" v-else src="../../../assets/audio/default-cover.png">
                 <div class="content">
                   {{ object.title | truncate(100) }}

front/tests/unit/specs/views/admin/library.spec.js

+const sinon = require('sinon')
+import { expect } from 'chai'
+import { shallowMount, createLocalVue } from '@vue/test-utils'
+import AlbumDetail from '@/views/admin/library/AlbumDetail.vue'
+import GetTextPlugin from 'vue-gettext'
+
+import HumanDate from '@/components/common/HumanDate.vue'
+import DangerousButton from '@/components/common/DangerousButton.vue'
+
+describe('views/admin/library', () => {
+
+  let wrapper
+  let sandbox
+  beforeEach(() => {
+    sandbox = sinon.createSandbox()
+  })
+  afterEach(() => {
+    sandbox.restore()
+  })
+  describe('Album details', () => {
+
+    it('displays default cover', async () => {
+      const album = { cover: null, artist: { id: null }, title: "dummy" }
+      const localVue = createLocalVue()
+      localVue.directive('title', (() => null))
+      localVue.directive('dropdown', (() => null))
+      localVue.use(GetTextPlugin, { translations: {} })
+      // overrides axios calls
+      sandbox.stub(AlbumDetail.methods, "fetchData").callsFake(() => null)
+      sandbox.stub(AlbumDetail.methods, "fetchStats").callsFake(() => null)
+      wrapper = shallowMount(AlbumDetail, {
+        localVue,
+        data() {
+          return {
+            isLoading: false,
+            isLoadingStats: false,
+            object: album,
+            stats: [],
+          }
+        },
+        mocks: {
+          $store: {
+            state: { auth: { profile: null }, ui: { lastDate: null } }
+          }
+        },
+        stubs: {
+          'human-date': HumanDate,
+          'dangerous-button': DangerousButton
+        },
+        computed: { labels: () => { return { statsWarning: null } } }
+      })
+      expect(wrapper.find('img').attributes('src')).to.include("default-cover")
+    })
+  })
+})
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