test: add minimal test for async service initialization

Author: Julien Heller

test/decorators/Service.spec.ts

@@ -172,5 +172,35 @@ describe('Service Decorator', function () {
     });
 
     expect(Container.get(TestService)).toBe('TEST_STRING');
+
+    it('should support services with asynchronous initialization', async function () {
+      @Service({ asyncInitialization: true })
+      class Engine {
+        ignition: string = 'off';
+        initialized: Promise<any>;
+
+        constructor() {
+          this.initialized = this.initialize();
+        }
+
+        protected initialize() {
+          return new Promise(resolve => {
+            setTimeout(() => {
+              this.ignition = 'running';
+              resolve();
+            }, 300);
+          });
+        }
+      }
+
+      @Service()
+      class Car {
+        constructor(public engine: Engine) {}
+      }
+
+      const car = await Container.getAsync<Car>(Car);
+
+      expect(car.engine.ignition).toEqual('running');
+    });
   });
 });