Moq with Entity Framework

moq-with-ef.cs

public static class QueryableExtensions
{
	public static Mock<DbSet<T>> ToMockDbSet<T>(this IQueryable<T> source)
		where T : class
	{
		var mock = new Mock<DbSet<T>>();

		mock.As<IQueryable<T>>()
			.Setup(x => x.Provider)
			.Returns(source.Provider);

		mock.As<IQueryable<T>>()
			.Setup(x => x.Expression)
			.Returns(source.Expression);

		mock.As<IQueryable<T>>()
			.Setup(x => x.ElementType)
			.Returns(source.ElementType);

		mock.As<IQueryable<T>>()
			.Setup(x => x.GetEnumerator())
			.Returns(source.GetEnumerator());

		mock.Setup(x => x.Attach(It.IsAny<T>())).Returns((T x) => x);

		mock.Setup(c => c.Include(It.IsAny<string>())).Returns(mock.Object);

		return mock;
	}
}

// using
var dbSet = new Cars[]{ new Car{ Id = 1}, new Car{ Id = 2}}.AsQueryable().ToMockDbSet();

var dataContext = new Mock<DataContext>();
dataContext.Setup(c => c.Cars).Returns(dbSet.Object);