EntityFramework_RepositoryTestingHelper

public static class RepositoryTestingHelper
{
  public static DbSet<T> GetQueryableMockDbSet<T>(List<T> sourceList) where T : class
  {
      var dbSet = GetMockDbSet(sourceList);
      return dbSet.Object;
  }

  public static Mock<DbSet<T>> GetMockDbSet<T>(List<T> entities) where T : class
  {
      var mockSet = new Mock<DbSet<T>>();

      mockSet.As<IQueryable<T>>().Setup(q => q.Provider).Returns(() => entities.AsQueryable().Provider);
      mockSet.As<IQueryable<T>>().Setup(q => q.Expression).Returns(() => entities.AsQueryable().Expression);
      mockSet.As<IQueryable<T>>().Setup(q => q.ElementType).Returns(() => entities.AsQueryable().ElementType);
      mockSet.As<IQueryable<T>>().Setup(q => q.GetEnumerator()).Returns(() => entities.AsQueryable().GetEnumerator());

      mockSet.Setup(set => set.Add(It.IsAny<T>())).Callback<T>(entities.Add);
      mockSet.Setup(set => set.AddRange(It.IsAny<IEnumerable<T>>())).Callback<IEnumerable<T>>(entities.AddRange);
      mockSet.Setup(set => set.Remove(It.IsAny<T>())).Callback<T>(t => entities.Remove(t));

      mockSet.Setup(set => set.RemoveRange(It.IsAny<IEnumerable<T>>())).Callback<IEnumerable<T>>(ts =>
      {
          foreach (var t in ts.ToList()) { entities.Remove(t); }
      });

      mockSet.Setup(set => set.AsNoTracking()).Returns(mockSet.Object);

      return mockSet;
  }
}