[REF] move component function to app, improve some code

tests/helpers.ts

@@ -91,7 +91,11 @@ export function renderToBdom(template: string, context: any = {}, node?: any): B
     snapshottedTemplates.add(template);
     expect(fn.toString()).toMatchSnapshot();
   }
-  return fn(null as any, blockDom, helpers)(context, node);
+  const app = {
+    createComponent() {},
+    createDynamicComponent() {},
+  };
+  return fn(app as any, blockDom, helpers)(context, node);
 }
 
 export function renderToString(template: string, context: any = {}, node?: any): string {