public async Task testChangeStarFail()
        {
            var options = new DbContextOptionsBuilder <ApplicationDbContext>()
                          .UseInMemoryDatabase(databaseName: "testChangeStarFail")
                          .Options;

            using (var context = new ApplicationDbContext(options))
            {
                context.Projects.Add(proj1);
                context.Projects.Add(proj2);
                context.Projects.Add(proj3);
                context.SaveChanges();
            };

            using (var context = new ApplicationDbContext(options))
            {
                var service = new ListController(context);
                var result  = await service.ChangeStar(vievProjNull);

                Assert.IsInstanceOfType(result, typeof(BadRequestObjectResult));
            }
        }