Testing API services using base classes/interfaces

Hi. Suppose, For example, I want to call a leaderboard service API.

Code (CSharp):

1.  
2. public async void GetLeaderboard(){
3.      var data=await new LeaderboardService().GetLeaderboard(top,count,LeaderboardName);
4. }

However I intend to utilize interfaces, so I can test services using fake/forged data and do not always need a real remote server.

How do you handle it?

1- Defining base abstract scriptableObjects for services with different implementations? (They can be serialized and I can utilize inspector serialization)
2- Using Dependency injection frameworks
3- Creating services in other classes and pass them into this class (Method injection)

Code (CSharp):

1. ILeaderboardService _service;
2. public void Initialize(ILeaderboardService service){
3.    _service=service;
4. }
5. ------------------------------------------------------------------------------------
6. public class LeaderboardServiceCreator:MonoBehaviour{
7.    [SerializeField] private LeaderboardController _leaderboardController;
8.    private void OnEnable(){          
9.         _leaderboardController.Initialize(new LeaderboardService());
10. //       _leaderboardController.Initialize(new TestLeaderboardService());
11.    }
12. }
13.