public async Task TestDeleteActivity()
        {
            var user = new ApplicationUser {
                Id = Guid.NewGuid().ToString(), UserName = "******"
            };
            var activity = new UserAction {
                Id = 1, ApplicationUser = user
            };
            var options = new DbContextOptionsBuilder <ApplicationDbContext>()
                          .UseInMemoryDatabase(databaseName: Guid.NewGuid().ToString()).Options;

            using (var db = new ApplicationDbContext(options))
            {
                IProfileService profileService = new ProfileService(db);
                db.Users.Add(user);
                db.UserActions.Add(activity);
                await db.SaveChangesAsync();

                await profileService.DeleteActivity(user);

                Assert.Equal(0, db.UserActions.Count());
            }
        }