Fix broken markdown field test

app/assets/javascripts/vue_shared/components/markdown/field.vue

@@ -64,12 +64,11 @@
           .then(resp => resp.json())
           .then((data) => {
             this.markdownPreviewLoading = false;
-            this.markdownPreview = data.body;
-            this.referencedCommands = data.references.commands;
-            this.referencedUsers = data.references.users;
+            this.markdownPreview = data.body || 'Nothing to preview.';
 
-            if (!this.markdownPreview) {
-              this.markdownPreview = 'Nothing to preview.';
+            if (data.references) {
+              this.referencedCommands = data.references.commands;
+              this.referencedUsers = data.references.users;
             }
 
             this.$nextTick(() => {

spec/javascripts/vue_shared/components/markdown/field_spec.js

@@ -92,6 +92,7 @@ describe('Markdown field component', () => {
 
       it('renders GFM with jQuery', (done) => {
         spyOn($.fn, 'renderGFM');
+
         previewLink.click();
 
         setTimeout(() => {
@@ -100,7 +101,7 @@ describe('Markdown field component', () => {
           ).toHaveBeenCalled();
 
           done();
-        });
+        }, 0);
       });
     });