public void AddExpenseTest()
        {
            var expectedExpense = GetNewMockExpense(collaborator.CollaboratorId, expenseStory.ExpenseStoryId);

            expenseManager.AddExpense(expectedExpense);
            var acutalExpense = dataContext.Expense.FirstOrDefault(x => x.ExpenseId == expectedExpense.ExpenseId);

            Assert.IsNotNull(acutalExpense);
            Assert.AreEqual(expectedExpense.GetHashCode(), acutalExpense.GetHashCode());
        }