public async void ReturnNull_InvalidId()
        {
            _unitOfWork.Setup(mock => mock.ActivityRepository.DeleteActivityResearcher(It.IsAny <int>()))
            .Returns(false);

            var command     = new DeleteActivityResearcherCommand(1);
            var handler     = new DeleteActivityResearcherHandler(_unitOfWork.Object);
            var returnValue = await handler.Handle(command, new CancellationToken());

            Assert.False((bool)returnValue);
        }
        public async void ReturnFalse_IfExceptionOccurs()
        {
            var exc = new Exception();

            _unitOfWork.Setup(mock => mock.ActivityRepository.ReadAllActivityForResearcher(It.IsAny <int>()))
            .Throws(exc);
            var command = new DeleteActivityResearcherCommand(10);

            var handler     = new DeleteActivityResearcherHandler(_unitOfWork.Object);
            var returnValue = await handler.Handle(command, new CancellationToken());

            Assert.False((bool)returnValue);
        }