week_3.markdown

Module 1 Week 3 Diagnostic.

• What do we mean when we talk about a variable's "scope"?

• a variable's scope is defined by where it is accessed, such as on a global, instance, or class level.

• Given the following code, what does the program output?

		def combine_variables(x)
		  puts "inner x is: #{x}"
		  puts "and outer b is: #{b}"
		end
		
		def b
		  12
		end
		
		a = 4
		combine_variables(a)

This program outputs the method call at the bottom, "combine_variables(a)" which works done the rest of the code where a is 4. It will return "inner x is 4 \n and outer b is 12

• What is the value of hero after this code has executed?

		new_creatures = ["IntrepidDecomposedCyclist", "Dragon"]
		villain = "AssistantViceTentacleAndOmbudsman"
		hero = "who knows"
		
		new_creatures.each do |villain|
		  hero = "Dwemthy"
		  puts "this time the villain is #{villain} and the hero is #{hero}"
		end

after code execution, the hero is "Dwemthy"

• What is a "handle" in terms of File I/O?

• a file handle is a method of interaction with a file

• What is the difference between "w", "r", and "a" modes in File I/O?

• when opening a file you can use options "w" = write, "r" = read, "a" = write (at the end of the file)

• Imagine we're writing software to model a Corgi dog. You don't need to write the implementation, but write a test for each of the following features:

• A Corgi has a name.

• A Corgi has an age.

• A Corgi can lie down.

• A Corgi can stand up.

• A Corgi cannot lie down when already lying down.

• A Corgi cannot stand when it is already standing.

• A Corgi starts hungry.

• A Corgi can eat, but only when it is hungry.

• A Corgi is no longer hungry when it has eaten three times.

class CorgiTest < Minitest::test

  def test_it_has_a_name
    corgi = Corgi.new
    assert_equal "Johnson", corgi.name
  end

  def test_it_has_an_age
    corgi = Corgi.new
    assert_equal 87, corgi.age
  end

  def test_it_can_lie_down
    corgi = Corgi.new
    assert_equal true, corgi.lying_down?
  end

  def test_it_can_stand_up
    corgi = Corgi.new

    corgi.stand_up
    assert_equal false, corgi.lying_down?
  end

  def test_it_cannot_lie_down_when_already_lying_down
    corgi = Corgi.new

    corgi.lie_down
    assert_equal "corgi is already laying down.", corgi.lie_down
  end

  def test_it_cannot_stand_up_when_already_standing
    corgi = Corgi.new

    corgi.stand_up
    assert_equal false, corgi.lying_down?

    corgi.stand_up
    assert_equal "corgi is already standing up.", corgi.stand_up
  end

  def test_it_gets_hungry
    corgi = Corgi.new

    assert_equal true, corgi.hungry?
  end

  def test_it_can_eat_but_only_when_hungry
    corgi = Corgi.new

    assert_equal "corgi cannot eat unless it is hungry.", corgi.eats
  end

  def test_it_can_eat_but_only_when_hungry
    corgi = Corgi.new

    corgi.hungry?
    assert_equal "corgi ate food.", corgi.eats
  end

  def test_it_is_no_longer_hungry
    corgi = Corgi.new

    corgi.hungry?
    assert_equal true, corgi.hungry?

    corgi.eats * 3
    assert_equal false, corgi.hungry?
  end
end