Behavior Driven Development (BDD) and DevExpress XAF
- by Patrick Liekhus
So in my previous posts I showed you how I used EDMX to quickly build my business objects within XPO and XAF. But how do you test whether your business objects are actually doing what you want and verify that your business logic is correct? Well I was reading my monthly MSDN magazine last last year and came across an article about using SpecFlow and WatiN to build BDD tests. So why not use these same techniques to write SpecFlow style scripts and have them generate EasyTest scripts for use with XAF. Let me outline and show a few things below. I plan on releasing this code in a short while, I just wanted to preview what I was thinking. Before we begin… First, if you have not read the article in MSDN, here is the link to the article that I found my inspiration. It covers the overview of BDD vs. TDD, how to write some of the SpecFlow syntax and how use the “Steps” logic to create your own tests. Second, if you have not heard of EasyTest from DevExpress I strongly recommend you review it here. It basically takes the power of XAF and the beauty of your application and allows you to create text based files to execute automated commands within your application. Why would we do this? Because as you will see below, the cucumber syntax is easier for business analysts to interpret and digest the business rules from. You can find most of the information you will need on Cucumber syntax within The Secret Ninja Cucumber Scrolls located here. The basics of the syntax are that Given X When Y Then Z. For example, Given I am at the login screen When I enter my login credentials Then I expect to see the home screen. Pretty easy syntax to follow. Finally, we will need to download and install SpecFlow. You can find it on their website here. Once you have this installed then let’s write our first test. Let’s get started… So where to start. Create a new testing project within your solution. I typically call this with a similar naming convention as used by XAF, my project name .FunctionalTests (i.e. AlbumManager.FunctionalTests). Remove the basic test that is created for you. We will not use the default test but rather create our own SpecFlow “Feature” files. Add a new item to your project and select the SpecFlow Feature file under C#. Name your feature file as you do your class files after the test they are performing. Now you can crack open your new feature file and write the actual test. Make sure to have your Ninja Scrolls from above as it provides valuable resources on how to write your test syntax. In this test below you can see how I defined the documentation in the Feature section. This is strictly for our purposes of readability and do not effect the test. The next section is the Scenario Outline which is considered a test template. You can see the brackets <> around the fields that will be filled in for each test. So in the example below you can see that Given I am starting a new test and the application is open. This means I want a new EasyTest file and the windows application generated by XAF is open. Next When I am at the Albums screen tells XAF to navigate to the Albums list view. And I click the New:Album button, tells XAF to click the new button on the list grid. And I enter the following information tells XAF which fields to complete with the mapped values. And I click the Save and Close button causes the record to be saved and the detail form to be closed. Then I verify results tests the input data against what is visible in the grid to ensure that your record was created. The Scenarios section gives each test a unique name and then fills in the values for each test. This way you can use the same test to make multiple passes with different data. Almost there. Now we must save the feature file and the BDD tests will be written using standard unit test syntax. This is all handled for you by SpecFlow so just save the file. What you will see in your Test List Editor is a unit test for each of the above scenarios you just built. You can now use standard unit testing frameworks to execute the test as you desire. As you would expect then, these BDD SpecFlow tests can be automated into your build process to ensure that your business requirements are satisfied each and every time. How does it work? What we have done is to intercept the testing logic at runtime to interpret the SpecFlow syntax into EasyTest syntax. This is the basic StepDefinitions that we are working on now. We expect to put these on CodePlex within the next few days. You can always override and make your own rules as you see fit for your project. Follow the MSDN magazine above to start your own. You can see part of our implementation below. As you can gather from the MSDN article and the code sample below, we have created our own common rules to build the above syntax. The code implementation for these rules basically saves your information from the feature file into an EasyTest file format. It then executes the EasyTest file and parses the XML results of the test. If the test succeeds the test is passed. If the test fails, the EasyTest failure message is logged and the screen shot (as captured by EasyTest) is saved for your review. Again we are working on getting this code ready for mass consumption, but at this time it is not ready. We will post another message when it is ready with all details about usage and setup. Thanks
