Typemock Isolator Plug (to get a free license and try out something other than Moq)

Programming Visual Basic applications?

Typemock have released a new version of their unit testing tool, Typemock Isolator 5.2. This version includes a new friendly VB.NET API which makes Isolator the best Isolation tool for unit testing A Visual Basic (VB) .NET application.

Isolator now allows unit testing in VB or C# for many ‘hard to test’ technologies such as SharePoint, ASP.NET MVC, partial support for Silverlight, WPF, LINQ, WF, Entity Framework, WCF unit testing and more.

Note that the first 25 bloggers who blog this text in their blog and tell us about it, will get a Free Full Isolator license (worth $139). If you post this in a VB.NET dedicated blog, you'll get a license automatically (even if more than 25 submit) during the first week of this announcement.

Go ahead, click the following link for more information on how to get your free license.

Evil Extension Method, or just handy?

 

I just realized I can have the following extension method:

   1: public static class StringExtensions

   2: {

   3:     public static bool HasContent(this string self)

   4:     {

   5:         return !string.IsNullOrEmpty(self);

   6:     }

   7: }

And then use it like this:

   1: [TestFixture]

   2: public class StringExtensionMethodsTest

   3: {

   4:     [Test]

   5:     [Category("Unit")]

   6:     public void TestStringHasContentWorksForNullStrings()

   7:     {

   8:         string s = null;

   9:         Assert.IsFalse(s.HasContent());

  10:     }

  11:  

  12:     [Test]

  13:     [Category("Unit")]

  14:     public void TestStringHasContentWorksForEmptyStrings()

  15:     {

  16:         string s = "";

  17:         Assert.IsFalse(s.HasContent());

  18:     }

  19:  

  20:     [Test]

  21:     [Category("Unit")]

  22:     public void TestStringHasContentWorksForStringsWithContent()

  23:     {

  24:         string s = "content";

  25:         Assert.IsTrue(s.HasContent());

  26:     }

  27: }

The interesting part is that a method call on a null object for an extension method works, which allows for the s.HasContent() idiom, instead of string.HasContent(s).

My question is the following: is relying on such “detail” good, in the way that it allows for less line noise and cleaner code, or bad for violating the idea that you can call a method on a null object and not get an exception?

I’d love to hear opinions on this.