add test

Author: christineweng

x-pack/platform/test/functional_with_es_ssl/apps/cases/group1/view_case.ts

@@ -915,6 +915,10 @@ export default ({ getPageObject, getService }: FtrProviderContext) => {
       it('adds a file to the case', async () => {
         await cases.casesFilesTable.addFile(require.resolve('./elastic_logo.png'));
 
+        // The files accordion only renders when the case has at least one
+        // file, so confirm it appears after the upload.
+        await testSubjects.existOrFail('case-view-attachment-accordion-file');
+
         // make sure the uploaded file is displayed on the table
         await find.byButtonText('elastic_logo.png');
       });