public void People_Should_Throw_ArgumentNullException_If_Customers_Is_Null()
{
IQueryable <Customer> customers = null;
var ex = Assert.Throws <ArgumentNullException>(() => CustomerExtensions.People(customers));
Assert.Equal(nameof(customers), ex.ParamName);
}
public void People_Should_Return_Only_Customer_Of_Type_Person()
{
var customer1 = Person.Register("firstName", "lastname", Gender.Female, new DateTime(1980, 1, 1));
var customer2 = Person.Register("firstName2", "lastname2", Gender.Male, new DateTime(1980, 1, 1));
var customer3 = Company.Register("company", "1234567890");
IQueryable <Customer> customers = new Customer[]
{
customer1, customer2, customer3
}.AsQueryable();
var people = CustomerExtensions.People(customers);
Assert.True(people.All(p => p is Person));
}