Angular test Class with service dependency

I'm trying to test a plain class (not a component) in Angular which has a service dependency and a separate constructor argument. I've mirrored the docs for component testing with a dependency, but I get the following error:

Unexpected value 'MyClass' imported by the module 'DynamicTestModule'. Please add a @NgModule annotation.

my-service.service.ts:

@Injectable({
providedIn: 'root',
})
export class MyService { ... }


my-class.ts:

import { inject } from '@angular/core';
import { MyService } from './my-service.service';

export class MyClass {
private _myService: MyService = inject(MyService);
private _name: string;

constructor(name: string) {
this._name = name;
}
}


my-class.spec.ts

import { ComponentFixture, TestBed } from '@angular/core/testing';
import { MyService } from './my-service.service';
import { MyClass } from './my-class';

describe('MyClass', () => {
let myClass: MyClass;
let mockMyService: Partial<MyService>;
let fixture: ComponentFixture<MyClass>;

beforeEach(() => {
mockMyService = {};

TestBed.configureTestingModule({
imports: [MyClass],
providers: [{ provide: MyService, useValue: mockMyService }],
});

fixture = TestBed.createComponent(MyClass); // causes error
myClass = fixture.componentInstance;

TestBed.inject(MyService);
});

it('should create', () => {
expect(myClass).toBeTruthy();
});
});


updated my-class.spec.ts

import { MyClass } from './my-class';

describe('MyClass', () => {
let myClass: MyClass;

beforeEach(() => {
myClass = new MyClass('someName');
});

it('should create', () => {
expect(myClass).toBeTruthy();
});
});


How can I test this plain class with the service dependency?

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