CSC/ECE 517 Fall 2011/ch2 2e kt

Ruby Testing Frameworks

Mini::Test TG

Evolution of Mini::Test

Although Ruby’s Test::Unit has been used for years and is a favorite (mostly due to its inclusion with the Ruby standard library), many Ruby developers felt the need for a more modern test infrastructure. This caused them to abandon Test::Unit and pull in additional test gems (e.g. rspec, shoulda, cucumber, etc.). With the new standard Mini::Test, however, this may be a thing of the past. Mini::Test was created to be small, clean and fast. Test::Unit could be rather slow and contained little-used features, such as test cases, GUI runners and some assertions. Mini::Test provides 90% of the functionality of Test::Unit that people were actually using, as well as some additional features.

Most of the assertions in Mini::Test are the same as those in its predecessor. The major difference is in the negative assertions. In Test::Unit where you have a assert_not_something method, Mini::Test provides a refute_something method. (assert_not_raise and assert_not_throws are no longer available.) Mini::Test provides the following assertions:

assert	assert_block	refute
assert_empty	assert_equal	refute_empty	refute_equal
assert_in_delta	assert_in_epsilon	refute_in_delta	refute_in_epsilon
assert_includes	assert_instance_of	refute_includes	refute_instance_of
assert_kind_of	assert_match	refute_kind_of	refute_match
assert_nil	assert_operator	refute_nil	refute_operator
assert_respond_to	assert_same	refute_respond_to	refute_same
assert_output	assert_raises
assert_send	assert_silent
assert_throws

Additional Features

Aside from the API improvements, Mini::Test also provides some additional features such as test randomization. In unit testing, tests should run independent from each other (i.e. the outcome or resulting state(s) of one test should not affect another). By randomizing the order, Mini::Test prevents tests from becoming order-dependent. Should you need to repeat the order to test for such issues, Mini::Test provides the current seed as part of the output and gives you the option to run the test using this same seed.

Mini::Test also gives you the ability to skip tests that are not working correctly (for debug at a later time). It also provides additional options for determining the performance of your test suite. But perhaps one of the best improvements is mini/spec - a BDD framework like RSpec for those programmers who prefer to use spec expectations over test assertions. Mini::Test contains the following expectations:

Code Example - TDD

require 'minitest/autorun'
require_relative 'account.rb'

class AccountTest < MiniTest::Unit::TestCase

  def setup
         @a = Account.new(100)
  end

  def test_deposit
    assert_equal(200, @a.deposit(100))
  end
 
  def test_withdrawal
    assert_equal(50, @a.withdrawal(50))
  end
 
  def test_name
    @a.name = "Checking"
    refute_nil(@a.name())
    assert_match(@a.name, "Checking")
  end

  def test_interest
    assert_in_delta(@a.addinterest(0.333), 130, 5)
  end

  def test_fail
    assert_equal(@a.balance(), 200)
  end
 
  def test_whatru
      assert_instance_of(Account, @a)
  end
     
end

Criteria

• IDE integration
• Test output detail
• Testing constructs available
• TDD or BDD
• Documentation
• Learning curve and ease of use

Framework Matrix

Framework	Website	Documentation	IDE Integration	Type	Ease of Use
Unit::Test
MiniTest::Unit	GitHub	RubyDoc

Demo Code

 class Account
   @balance
   @name
 
   attr_accessor :balance
   attr_accessor :name
 
   def initialize(amount)
     @balance = amount
   end
 
   def deposit(amount)
     @balance += amount
   end
 
   def addinterest(rate)
     @balance *= (1 + rate)
   end
 
   def withdrawal(amount)
     @balance -= amount
   end
 end

Test::Unit

 require "test/unit"
 require_relative("../Account.rb")
 
 class AccountTest < Test::Unit::TestCase
 
   def test_balance
     a = Account.new(100)
     assert_equal(100, a.balance())
   end
 
   def test_deposit 
     a = Account.new(100)
     assert_equal(200, a.deposit(100))
   end
   
   def test_withdrawal
     a = Account.new(100)
     assert_equal(50, a.withdrawal(50))
   end
   
   def test_name
     a = Account.new(100)
     a.name = "Checking"
     assert_not_nil(a.name())
   end
 
   def test_interest
     a = Account.new(100)
     assert_equal(a.addinterest(0.5), 150)
   end
 
   def test_fail
     a = Account.new(100)
     assert_equal(a.balance(), 200)
   end
 end

References

[1] http://ruby-toolbox.com/categories/testing_frameworks.html