CSC/ECE 517 Fall 2011/ch2 2e ad

Testing frameworks for Ruby

Introduction

This is an introduction to the subject.

Testing Framework Evolution

Explain here how testing in ruby went from regular Test:unit testing to BDD testing.

TDD vs BDD

Give high level example how they differ from each other.

Ruby Testing Frameworks

Compared to five years ago the number of testing framework available for ruby has increased rapidly. Selecting a perfect testing framework for a particular project has become harder.

Overview of testing framework

Selection of testing framework for ruby projects depends on factors like what are we trying to accomplish TDD or BDD, is GUI testing included, is acceptance testing required, do we have to merge legacy ruby test code with new testing framework. Altough GUI testing and acceptance testing are out of scope for this wiki we have made attempt to cover them in some details at the end of this wiki page. Meanwhile, below is the detailed explanation of five most commonly used unit testing framework.

Test:Unit

Test-Unit is one of the oldest testing frameworks for ruby testing. Test-Unit is basically used for performing test driven development same as how Java’s JUnit is used. It’s in a way very similar to java’s JUnit. Test-Unit framework when initially released was part of the ruby distribution package. The newer version since then has been converted to gems and has been provided to developers as a standalone package. Additionally some of the features like notify, capybara, GTK+, Tk, and FOX Toolkit have been split from package and provided as a separate packages.

RSpec

RSpec is a Behavior-Driven Development tool for Ruby programmers. As defined earlier BDD is an approach to software development that combines Test-Driven Development, Domain Driven Design, and Acceptance Test-Driven Planning. RSpec helps you do the TDD part of that equation, focusing on the documentation and design aspects of TDD [1]

RSpec is one of the most widely used testing frameworks for ruby. The main difference between RSpec and Test-Unit is semantics. RSpec provides a way to write tests which are more in human readable form. This reduces the expense for maintaining the test and also provides more easily understandable tests. Additionally when RSpec tests fails it provides more information about what functionality failed and why compared to Test-Unit test where you have to put custom messages on all assertion statements to point out exactly what happened.

Riot

Riot is another BDD ruby unit testing framework. Riot testing framework is a mixture of both RSpec and Test-Unit or should say RSpec and Shoulda (which is based on Test-Unit). The main purpose of the author of Riot testing framework was to come up with some ruby testing framework which is fast in execution but is in more human readable form. As in case of other testing framework Riot does not have variables described or initialized in its test cases. It has a setup block which returns a variable as default. This allows Riot to be fast during execution as it does not have to initialize or do much of pre-test setup. One of the uniqueness about Riot testing framework is that the tests only focuses on small functionality.

Testing Framework Details

---

Testing Framework	Released Date	Released Version	Current Version	Testing Type Supported	Install Command	Documentation/Version Support
Test:Unit	03-20-2008	1.2.3	2.4.0	TDD,Mocking	gem install test-unit	Test:Unit Site Versions
Shoulda	04-26-2008	4.1	2.11.3	BDD,TDD	gem install shoulda	Shoulda Site Versions
RSpec	05-26-2008	1.1.4	2.6.0	BDD,TDD, DDD (Domain Driven Design)	gem install rspec	RSpec Site Versions
Riot	10-19-2009	0.9.11	0.12.5	BDD,TDD	gem install riot	Riot Site Versions
MiniTest	06-10-2008	1.2.1	2.6.9	TDD,Mocking	gem install minitest	Minitest Site
Cucumber	05-20-2009	0.3.6	1.0.6	Acceptance Testing	gem install cucumber	Cucumber Site Versions

Examples

Above we described how each ruby testing framework differ from each other. But to better understand each testing framework let go through a single example with tests written in most testing framework described above.

TravelTime

The example that we have used below is a simple travel time example. All it does is if you give it a distance between two cities it will calculate the time it will take you to travel from City A to City B. It assumes that you will be driving at 60 miles/Hr with minimal traffic on the road.

class TravelTime
   attr_accessor :distance
  
  #Divide the distance by 60 and return the float
  def time_to_travel
    @time = @distance.fdiv(60)
  end

  #Format the float to two decimal and return the string
  def format_time_to_travel(time)
    @time = format("%3.2f",time)
  end
  
  def initialize(distance)
    @distance = distance
  end
end

The code above has two functions and one initialize function. The initialize function takes in distance between two cities and stores it into distance variable. The first function time_to_travel when called calculates the time it takes to travel by dividing the distance provided during initialize stage by 60 (for 60 miles/hr speed). This function returns a float value as time. The second function format_time_to_travel all it does is if you provide a float number it will format the float number up to two decimal points and return the string. This function will be used in cases where you get a big float number for time like 2.36666667 hrs and you just want it to be 2.37 than you can pass the float number to get 2.37 hrs. Now lets see how this functions can be tested in different testing framework.

Test-Unit

The first test framework that we are going to use is Test-Unit. As you can see from the code below its similar to Java JUnit if you are familiar with JUnit. TimeTravelTest_TU class below has setup function which is used for setting up pretest data before running tests. In our case we have initialized three different instances of TravelTime class with distances 120 150 and 135 miles. The class also has a teardown function which can be used to discard all the data that were created before or during test execution. The remaining three functions are the actual tests that will be performed one this test is executed.

gem 'test-unit'
require 'test/unit'
require File.dirname(__FILE__) + '/travel_time'

class TimeTravelTest_TU < Test::Unit::TestCase

  # Called before every test method runs. Can be used
  # to set up fixture information.
  def setup
    @traveltime1 = TravelTime.new(120)
    @traveltime2 = TravelTime.new(150)
    @traveltime3 = TravelTime.new(135)
  end

  def teardown
    # Do nothing
  end

  def test_time_to_travel_integer
    time = @traveltime1.time_to_travel
    assert_equal 2.0, time
  end

  def test_time_to_travel_floatWithOneDecimal
    time = @traveltime2.time_to_travel
    assert_equal 2.5, time
  end

  def test_time_to_travel_floatWithTwoDecimal
    temp = @traveltime3.time_to_travel
    time = @traveltime3.format_time_to_travel(temp)
    assert_equal "2.25", time
  end

end

The first test function is to test if you provide the distance of 120 miles does it return the travel time to be 2 hrs. The second test function tests if you provide 150 miles distance does it come back with 2.5 hrs. And the last test function checks if you get travel time in a big floating number like 2.2444445 hours can you correctly format that result to 2.25 hours. We have used different instances of travel time class for different tests the reason for doing this is to see if the performance suffers between test frameworks due to this.

Finished in 0.004 seconds.

3 tests, 3 assertions, 0 failures, 0 errors, 0 pendings, 0 omissions, 0 notifications
100% passed

RSpec testing code

gem 'rspec'
require File.dirname(__FILE__) + '/travel_time'
#spec TravelTimeTest_RSpec.rb --format specdoc

describe TravelTime do

  it "should be 2.0 hours when distance is 120 miles" do
    @traveltime1 = TravelTime.new(120)
    time = @traveltime1.time_to_travel
    time.should be == 2.0
  end

  it "should be 2.5 hours when distance is 150 miles" do
    @traveltime1 = TravelTime.new(150)
    time = @traveltime1.time_to_travel
    time.should be == 2.5
  end

  it "should be 2.25 hours when distance is 135 miles" do
    @traveltime1 = TravelTime.new(135)
    temp = @traveltime1.time_to_travel
    time = @traveltime1.format_time_to_travel(temp)
    time.should be == "2.25"
  end

end

TravelTime
- should be 2.0 hours when distance is 120 miles
- should be 2.5 hours when distance is 150 miles
- should be 2.25 hours when distance is 135 miles

Finished in 0.284016 seconds

3 examples, 0 failures

Riot testing code

gem 'riot'
require 'riot'
require File.dirname(__FILE__) + '/travel_time'

context TravelTime do
  setup {TravelTime.new(120)}
  asserts("Travel time is 2.0 hours when distance is 120 miles"){
    topic.time_to_travel == 2.0
  }
end

context TravelTime do
  setup {TravelTime.new(150)}
  asserts("Travel time is 2.5 hours when distance is 150 miles"){
    topic.time_to_travel == 2.5
  }
  end

context TravelTime do
  setup {TravelTime.new(135)}
  asserts("Travel time is 2.25 hours when distance is 135 miles"){
    topic.format_time_to_travel(topic.time_to_travel) == "2.25"
  }
end

TravelTime
  + asserts Travel time is 2.0 hours when distance is 120 miles
TravelTime
  + asserts Travel time is 2.5 hours when distance is 150 miles
TravelTime
  + asserts Travel time is 2.25 hours when distance is 135 miles

3 passes, 0 failures, 0 errors in 0.005 seconds

Shoulda testing code

gem 'shoulda'
gem 'shoulda-context'
gem 'test-unit'
require 'test/unit'
require File.dirname(__FILE__) + '/travel_time'

class TravelTimeTest_Shoulda < Test::Unit::TestCase
  context TravelTime do
    setup do
      @traveltime1 = TravelTime.new(120)
      @traveltime2 = TravelTime.new(150)
      @traveltime3 = TravelTime.new(135)
    end

    should "be 2.0 hours when distance is 120 miles" do
      time = @traveltime1.time_to_travel
      assert_equal 2.0,time
    end

    should "be 2.5 hours with one decimal point when distance is 150 miles" do
      time = @traveltime2.time_to_travel
      assert_equal 2.5,time
    end

    should "be 2.25 hours with two decimal point limit when distance is 135 miles" do
      temp = @traveltime3.time_to_travel
      time = @traveltime3.format_time_to_travel
      assert_equal "2.25",time
    end

  end
end

References

• [1] Ruby Forge Test:Unit Site
• [2] Shay Friedman A Mini-Review-Benchmark of Ruby’s Different Testing Frameworks

Note

There are many testing frameworks for Rails, but for this topic, I would like you to concentrate on testing frameworks for Ruby itself. Look up information on these frameworks, and describe their evolution.