public async Task GroupRepository_Add_User_To_Group() { //Arrange var dbContext = _fixture.DbContext; IGroupRepository repository = new GroupRepository(dbContext); var group = dbContext.Groups.FirstOrDefault(); var user = dbContext.Users.FirstOrDefault(); var userGroup = new UserGroup(); userGroup.GroupId = group.Id; userGroup.UserId = user.Id; var ug = dbContext.UserGroups.FirstOrDefault(x => x.UserId == user.Id && x.GroupId == group.Id); if (ug != null) { dbContext.UserGroups.Remove(ug); dbContext.SaveChanges(); } //Act await repository.AddUserToGroupAsync(userGroup); await repository.SaveAsync(); //Assert Assert.Contains(userGroup, dbContext.UserGroups); }