public void AddStudentTest() { // Arrange var mockSet = new Mock <DbSet <Student> >(); var mockContext = new Mock <ExamDbContext>(); mockContext.Setup(m => m.Students).Returns(mockSet.Object); // Result var service = new StudentDbRepository(mockContext.Object); service.AddStudent(_studentsdata.ElementAt(0)); // Assert mockSet.Verify(m => m.Add(It.IsAny <Student>()), Times.Once()); mockContext.Verify(m => m.SaveChanges(), Times.Once()); }