Add flash message to submission details page for submission deletion

app/controllers/submissions/detail.js

@@ -474,10 +474,17 @@ export default class SubmissionsDetail extends Controller {
     if (result.value) {
       const ignoreList = this.searchHelper;
 
-      await this.submissionHandler.deleteSubmission(submission);
-      ignoreList.clearIgnore();
-      ignoreList.ignore(submission.get('id'));
-      this.transitionToRoute('submissions');
+      try {
+        await this.submissionHandler.deleteSubmission(submission);
+
+        ignoreList.clearIgnore();
+        ignoreList.ignore(submission.get('id'));
+        this.transitionToRoute('submissions');
+      } catch (e) {
+        this.flashMessages.danger(
+          'We encountered an error deleting this draft submission. Please try again later or contact your administrator'
+        );
+      }
     }
   }
 }

tests/unit/controllers/submissions/detail-test.js

@@ -1,6 +1,7 @@
 import EmberObject from '@ember/object';
 import { module, test } from 'qunit';
 import { setupTest } from 'ember-qunit';
+import Sinon from 'sinon';
 
 module('Unit | Controller | submissions/detail', (hooks) => {
   setupTest(hooks);
@@ -38,4 +39,30 @@ module('Unit | Controller | submissions/detail', (hooks) => {
 
     controller.send('deleteSubmission', submission);
   });
+
+  test('error message shown on submission deletion error', async function (assert) {
+    const submission = {};
+
+    // Mock global SweetAlert. Mocks a user clicking OK on the popup
+    swal = Sinon.fake.resolves({ value: true });
+
+    const controller = this.owner.lookup('controller:submissions/detail');
+    const transitionFake = Sinon.replace(controller, 'transitionToRoute', Sinon.fake());
+
+    controller.submissionHandler = this.owner.lookup('service:submission-handler');
+    const deleteFake = Sinon.replace(controller.submissionHandler, 'deleteSubmission', Sinon.fake.rejects());
+
+    controller.flashMessages = this.owner.lookup('service:flash-messages');
+    const flashFake = Sinon.replace(controller.flashMessages, 'danger', Sinon.fake());
+
+    // Note: using controller.send resolves immediately
+    // making subsequent assertions evaluate before the controller action fires
+    // Can't really use Sinon in a nice way unless we call the controller
+    // method directly
+    await controller.deleteSubmission(submission);
+
+    assert.ok(deleteFake.calledOnce, 'Submission handler delete should be called');
+    assert.ok(flashFake.calledOnce, 'Flash message should be called');
+    assert.equal(transitionFake.callCount, 0, 'Transition should not be called');
+  });
 });