@NgModule({
  declarations: [ ... ,
    CalendarComponent,
  ],
  imports: [ ... ,
    TestModule,
  ],
  exports: [ ...
    CalendarComponent,
  ],
  providers: [ ... ],
  bootstrap: [AppComponent]
})

@NgModule({
  declarations: [ ... ,
    TestComponent
  ],
  imports: [ ... ],
  exports: [ ... ],
  providers: [ ... ]
})

<app-calendar></app-calendar>