How are people unit testing code that uses Linq to SQL

Question

How are people unit testing code that uses Linq to SQL?

Answer 1

3 years late, but this is how I do it:

https://github.com/lukesampson/LinqToSQL-test-extensions/

No need to write a wrapper or do lots of plumbing, just drop the T4 template next to your .dbml and you get:

1. An interface for your data context e.g. IExampleDataContext
2. An in-memory mock for your data context e.g. MemoryExampleDataContext

Both will automatically use the mappings you've already configured in your DBML.

So you can do things like

public class ProductRepo {
    IExampleDataContext DB { get; set };
    public ProductRepo(IExampleDataContext db) {
        DB = db;
    }

    public List GetProducts() {
        return DB.Products.ToList();
    }
}

and you can call that with either

new ProductRepo(new MemoryExampleDataContext()).GetProducts(); // for testing

or

new ProductRepo(new ExampleDataContext()).GetProducts(); // use the real DB