MSDN Magazine - February 2009 - (Page 61)

the way you write the examples, including the terminology you use, the way you organize the methods, and how easily the concept can be understood compared to TDD. With BDD and RSpec, together with the close integration of IronRuby and the .NET Framework, you can start using IronRuby to test C# applications. In terms of an example, the classic RSpec example is the Bowling game. First, you need to access the bowling game’s implementation in a C# assembly: require File.dirname(__FILE__) + \ '/InteropSamples/Bowling/Bowling/bin/Debug/bowling.dll' To download the source code, you will need to have a Git source control client, such as msysgit, installed (see git.or.cz for more). The IronRuby source control URL is git://github.com/ironruby/ironruby.git. If you would like more information then I recommend you visit the project site at rubyforge.org/projects/ironruby/ or my blog post (blog.benhall.me.uk/2008/12/downloading-ironruby-from-github.html). Once you have downloaded the source code, you can compile the assembly either with Visual Studio using the IronRuby.sln solution file or, if you have MRI installed, then you can use the command: rake compile You then need to access RSpec: require 'rubygems' require 'spec' Now you can begin writing examples. This is an example showing how bowling implementation should work. RSpec has a Domain Specific Language (DSL) that you must follow for the examples to be executable. The first part of the DSL is the describe block. Here you simply state the object you are “describing” together with an optional description. In this case, I define the Bowling object, which will be implemented in C#: describe Bowling, " defines the bowling game" do Once you have IronRuby compiled, you must download various libraries, such as RSpec, to gain the extra functionality. Ruby has a concept of RubyGems where the gems are packages you can download to gain the functionality and the additional dependencies. To download RSpec, type the following at a command prompt: gem install rspec You would now be able to access the RSpec library from within your Ruby code. However, at the time of writing, RSpec does not work with IronRuby due to one or two bugs. Hopefully by the time this To improve readability, any setup will be performed within a before block: before(:each) do @bowling = Bowling.new End I am now in a position to interact with the object, create the example and verify that it works correctly. I use the “it” block, providing a string stating the context of the example and what it is demonstrating. I then write the section of code that interacts with the system and verifies the correct action has happened: it "should score 0 for a gutter game" do 20.times { @bowling.hit(0) } @bowling.score.should == 0 end end RubyGems are packages you can download to include additional functionality. article is published RSpec should be working with IronRuby. To find out the status of the RSpec support, see the RSpec Web site at rspec.info or the IronRuby mailing list at rubyforge.org/mail/?group_id=4359. If the bug hasn’t been fixed, I have made a binary with the bug fixed, together with the RSpec library in place, ready for you to use, at blog.benhall.me.uk/downloads/IronRuby/MSDNBuild.zip. (Note: don’t use this version once the team has fixed the problem.) Once you have the correct binaries in place, ir.exe is the IronRuby interpreter that can execute your code. If you simply launch the app from the command line, you’ll enter the interactive console. In Ruby, code is executed on a line-by-line basis, excellent for learning and debugging, but also for running short commands to solve daily problems. If you provide a file name as a parameter, then the file is executed with the results output to the console. The C# implementation simply looks like this: public class Bowling { public int Score { get; set; } public void Hit(int pins) { Score += pins; } } Finally, execute this to verify that the bowling example works as expected with RSpec testing C# objects: >ir bowling_spec.rb . Finished in 1.0458315 seconds 1 example, 0 failures If I wanted a more detailed report, I could select the format to be specdoc. This outputs the object description together with all the examples, stating if they have passed or not: >ir bowling_spec.rb --format specdoc Bowling defines the bowling game - should score 0 for a gutter game Finished in 1.43728 seconds 1 example, 0 failures Moving Forward In my next article, I will introduce the concept of acceptance testing and how it can improve communication between customer and developer. I will demonstrate how acceptance testing can be automated using IronRuby and RSpec to verify .NET applications and create an executable specification for the system.  Ben Hall is a C# developer/tester with a strong passion for software development and loves writing code. Ben works at Red Gate Software in the U.K. as a Test Engineer and enjoys exploring different ways of testing software, including both manual and automated testing, focusing on the best ways to test different types of applications. Ben is a C# MVP and maintains a blog at Blog.BenHall.me.uk. February 2009 61 At the time of writing, the IronRuby team is not regularly shipping binaries. The team has said it is waiting until it is happy with the implementation, compatibility, and performance before releasing official binaries. However, because the source code is freely available, you can download the code and build it yourself. msdnmagazine.com http://git.or.cz http://github.com/ironruby/ironruby/tree/master http://www.rubyforge.org/projects/ironruby/ http://blog.benhall.me.uk/2008/12/downloading-ironruby-from-github.html http://blog.benhall.me.uk/2008/12/downloading-ironruby-from-github.html http://www.rspec.info http://www.rubyforge.org/mail/?group_id=4359 http://blog.benhall.me.uk/downloads/IronRuby/MSDNBuild.zip http://Blog.BenHall.me.uk http://www.msdnmagazine.com

Table of Contents Feed for the Digital Edition of MSDN Magazine - February 2009

MSDN Magazine - February 2009 Contents Toolbox CLR Inside Out Data Points Cutting Edge Patterns In Practice Best Practices .Net Interop "Oslo" Basics Patterns Silverlight Under The Table Foundations Windows With C++ .NET Matters Going Places { End Bracket }

MSDN Magazine - February 2009

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