public void TestFirstOrDefault()
{
var employees = RepositoryFactory.GetEmployees();
Assert.Equal("Kevin", WithoutLinq.CashFirstOrDefault(employees, a => a.MonthSalary > 200).Name);
Assert.Null(WithoutLinq.CashFirstOrDefault(employees, a => a.MonthSalary > 500));
Assert.Equal("Kevin", employees.CashFirstOrDefault(a => a.MonthSalary > 200).Name);
Assert.Null(employees.CashFirstOrDefault(a => a.MonthSalary > 500));
}