fix: 🐛 role discard should not error (#1226)

addons/api/addon/models/role.js

@@ -27,7 +27,9 @@ export default class RoleModel extends GeneratedRoleModel {
    * Convenience for looking up the grant scope, if loaded.
    */
   get grantScope() {
-    return this.store.peekRecord('scope', this.grant_scope_id);
+    return this.grant_scope_id
+      ? this.store.peekRecord('scope', this.grant_scope_id)
+      : null;
   }
 
   // =methods

addons/api/mirage/factories/credential-store.js

@@ -23,7 +23,7 @@ export default factory.extend({
       case 'static':
       default:
         return {
-          'credentials': ['create', 'list'],
+          credentials: ['create', 'list'],
         };
     }
   },

addons/api/mirage/factories/credential.js

@@ -18,4 +18,4 @@ export default factory.extend({
       username: random.word(),
     };
   },
-});
+});

addons/api/tests/unit/models/credential-test.js

@@ -1,11 +1,11 @@
 import { module, test } from 'qunit';
 import { setupTest } from 'ember-qunit';
 
-module('Unit | Model | credential', function(hooks) {
+module('Unit | Model | credential', function (hooks) {
   setupTest(hooks);
 
   // Replace this with your real tests.
-  test('it exists', function(assert) {
+  test('it exists', function (assert) {
     let store = this.owner.lookup('service:store');
     let model = store.createRecord('credential', {});
     assert.ok(model);