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());
}