Enabling Modular Testing via Interface Injection

Snippet

Enabling Modular Testing via Interface Injection

By requiring an interface in the constructor rather than a concrete class, you decouple the business logic from infrastructure. This makes unit testing possible because you can inject a 'mock' implementation of the interface that doesn't touch a real database or file system.

snippet.cs

csharp

public interface IDataStore { void Save(string data); }
 
public class Processor
{
    private readonly IDataStore _store;
    public Processor(IDataStore store) => _store = store;
 
    public void Run(string input)
    {
        // Logic here...
        _store.Save(input);
    }
}

Breakdown

public interface IDataStore

Defines a contract for saving data without specifying how it's done.

public Processor(IDataStore store)

The constructor accepts any object that implements the interface (Dependency Injection).

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Enabling Modular Testing via Interface Injection

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