public void DeleteRecordTest() { var data = new List <customer> { new customer { cust_name = "AAAAA", cust_address = "AAA" } }.AsQueryable(); var mockSet = new Mock <DbSet <customer> >(); mockSet.As <IQueryable <customer> >().Setup(m => m.Provider).Returns(data.Provider); var mockContext = new Mock <pharmacydbEntities>(); mockContext.Setup(c => c.customers).Returns(mockSet.Object); var service = new DbOperation(mockContext.Object); var customer = service.DeleteRecord("EmadEmad"); Assert.AreEqual(customer, "EmadEmad"); }