Writing tiny tests

exercise_1a_array_test.rb

require 'minitest/autorun'

class ArrayTest < MiniTest::Test
  def test_new_array_has_zero_size
    assert(Array.new.size == 0)
  end

  def test_new_array_is_empty
    assert(Array.new.empty?)
  end

  def test_empty_array_is_equivalent
    assert(Array.new == [])
  end

  def test_initialized_arary_is_equivalent
    assert(Array.new([1,2,3]) == [1,2,3])
  end

  def test_pop_the_top
    assert(Array.new([1,2,3]).pop == 3)
  end

  def test_pop_removes_the_top
    assert(Array.new([1,2,3]).tap {|a| a.pop } == [1,2])
  end

  # Lots more methods to document in http://www.ruby-doc.org/core-2.1.2/Array.html
end

exercise_1b_string_test.rb

require 'minitest/autorun'

class StringTest < Minitest::Test
  def test_new_string_equals_empty_string
    assert(String.new == "")
  end

  def test_capitalize_downcases_all_but_first
    assert("hello Pat how are you?".capitalize == "Hello pat how are you?")
  end

  def test_downcase_makes_all_letters_small
    assert("Hi I LOVE RubySteps".downcase == "hi i love rubysteps")
  end

  def test_gsub_substitutes_string
    assert("I dislike RubySteps".gsub("dislike", "love") == "I love RubySteps")
  end

  def test_string_interning
    assert("I know that 1 + 1 = #{1 + 1}" == "I know that 1 + 1 = 2")
  end

  # Check out http://www.ruby-doc.org/core-2.1.2/String.html for even more methods...
end

exercise_1c_hash_test.rb

require 'minitest/autorun'

class HashTest < Minitest::Test
  def test_new_hash_is_equivalent
    assert(Hash.new == {})
  end

  def test_default_value_is_nil
    assert({}[:funky] == nil)
  end

  def test_set_default_value_on_initialize
    assert(Hash.new("chicken")[:funky] == "chicken")
  end

  def test_set_value_overrides_default_value
    assert(Hash.new("chicken").tap {|hash| hash[:funky] = "James Brown" }[:funky] == "James Brown")
  end

  def test_hash_with_initializer_sets_value
    assert(Hash.new {|hash, k| k.to_s.upcase }[:funky] == "FUNKY")
  end

  # Plenty more in http://www.ruby-doc.org/core-2.1.2/Hash.html
end

exercise_1d_enumerable_test.rb

require 'minitest/autorun'

class EnumerableTest < Minitest::Test
  def test_all_is_true
    assert([1,3,5,7].all?(&:odd?))
  end

  def test_all_is_false
    assert(![1,2,3].all?(&:odd?))
  end

  def test_any_is_true
    assert([1,2].any?(&:odd?))
  end

  def test_any_is_false
    assert(![2,4].any?(&:odd?))
  end

  def test_select_chooses_items
    assert([1,2,3,4,5].select(&:odd?) == [1,3,5])
  end

  # Lots more in http://www.ruby-doc.org/core-2.1.2/Enumerable.html
end

exercise_2_custom_code_test.rb

require 'minitest/autorun'

class RubySteps
  def fun!
    true
  end

  def educational?
    true
  end

  def about
    ['ruby', 'rails', 'tdd', 'oop', 'refactoring']
  end
end

class RubyStepsTest < Minitest::Test
  def test_ruby_steps_is_fun
    assert(RubySteps.new.fun! == true)
  end

  def test_ruby_steps_is_educational
    assert(RubySteps.new.educational? == true)
  end

  def test_ruby_steps_is_about_good_stuff
    assert(RubySteps.new.about == %w(ruby rails tdd oop refactoring))
  end
end

exercise_3a_tiny_test_framework.rb

def verify(name, &block)
  raise "Failed test: #{name}" unless block.call
end

verify "1 is #odd?" do
  1.odd?
end

verify "2 is #even?" do
  2.even?
end

exercise_3b_tiny_test_failure.rb

def verify(name, &block)
  raise "Failed test: #{name}" unless block.call
end

verify "1 is #odd?" do
  2.odd?
end

verify "2 is #even?" do
  1.even?
end

exercise_3c_tiny_test_reporting.rb

def verify(name, &block)
  puts "Failed test: #{name}" unless block.call
end

verify "1 is #odd?" do
  2.odd?
end

verify "2 is #even?" do
  1.even?
end