title: How to solve/suppress IntelliJ warning that mock class is not declared in any Angular module?
body: <p>I have an angular 8 app where I am trying to mock some sub components.</p>
  
  <p>The mocking itself is fine. However for the sake of organization and re-usability, I want to move the mocks out of the .spec file and into its own mock directory as shown below</p>
  
  <pre><code>myApp
  |-- src
      |-- app
          |-- app.component.spec.ts
      |-- mocks
          |-- material
              |-- mat-drawer-container.ts
  </code></pre>
  
  <p>The mock for MaterialDrawerContainer looks like this:</p>
  
  <pre><code>import {Component, Input} from '@angular/core';
  
  @Component({
     selector: 'mat-drawer-container',
     template: ''
  })
  
  export class MockMatDrawerContainer {
  @Input() mode;
  }
  </code></pre>
  
  <p>The test itself still works as expected. But annoyingly, there's a big old red line underneath MockMatDrawerContainer complaining that "MockMatDrawerContainer is not declared in any angular module" even though it is used in the testbed configure test module like so: </p>
  
  <pre><code>TestBed.configureTestingModule(
              {declarations: [MockMatDrawerContainer]}).compileComponents;
  </code></pre>
  
  <p>I have found the stackoverflow suggestions for "Compile on changes" and related changes to tsconfig.app.json for compileOnSave but nothing helps except to create a bogus ngModule in mock directory, which seems silly.</p>
  
  <p>Any words of wisdom?</p>