Decoupling Logic for Testability

Snippet

Decoupling Logic for Testability

Using interfaces allows for dependency injection, which is critical for unit testing. By depending on IEmailService rather than a concrete class, you can easily inject a mock implementation during tests to verify behavior without sending real emails.

snippet.cs

csharp

public interface IEmailService
{
    void Send(string message);
}
 
public class NotificationManager
{
    private readonly IEmailService _service;
    public NotificationManager(IEmailService service) => _service = service;
 
    public void Notify(string msg)
    {
        if (string.IsNullOrEmpty(msg)) return;
        _service.Send(msg);
    }
}

Breakdown

public interface IEmailService

Defines a contract that can be swapped with a mock during testing.

public NotificationManager(IEmailService service)

The constructor receives the implementation, enabling loose coupling.

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Decoupling Logic for Testability

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