jbevarts

a = [ "a", "b", "c", "d", "e" ]
a[6, 1]                #=> nil
a[5, 1]                #=> []


# I don't understand why these are different.

jbevarts

# nice
def test_you_dont_get_null_pointer_errors_when_calling_methods_on_nil
    nil.some_method_nil_doesnt_know_about
  rescue ex = Exception.new
    assert_equal NilClass, ex.class
    assert_match(/NoMethodError/, ex.message)
end

# not nice
def test_you_dont_get_null_pointer_errors_when_calling_methods_on_nil   

jbevarts

class Account
  attr_reader :name,:balance
  def initialize(name,balance=100)
    @name = name
    @balance = balance
  end
  
  def display_balance(pin_number)
    puts pin_number == pin ? "Balance: $#{@balance}" : pin_error
  end