test(in-memory-db): update test for new version of nx

Author: yharaskrik

packages/in-memory-db/src/schematics/nest-add/index.spec.ts

@@ -28,9 +28,11 @@ describe('nest add function', () => {
     runner = new SchematicTestRunner('schematics', collectionPath);
   });
 
-  it('should add package to module', () => {
-    const ngAddTree = runner.runSchematic('nest-add', '', tree);
+  it('should add package to module', async (done) => {
+    const ngAddTree = await runner.runSchematicAsync('nest-add', '', tree).toPromise();
     const module = ngAddTree.readContent('/src/app.module.ts');
     expect(module).toMatchSnapshot();
+
+    done();
   });
 });