Home TDD, IoC, and Mock Framework

TDD, IoC, and Mock Framework

My experience is that some cool terms always come together. In my case the three words are: TDD, IoC, and mock framework. If you never knew how these terms connect to each other, I can tell you my story.

Two weeks ago I decided to add a new feature in CBC that helps sign a Delphi for .NET project in Visual Studio way. And this time, I want to try TDD on this feature.

The development became difficult at first because I thought it was impossible to test a Delphi IDE wizard. However, after setting up a small unit case, I found my way and wrote out a few ugly lines to pass the test. However, there were a few issues that violated TDD principles,

  1. The test could not run automatically because there were a few message boxes.
  2. The code invokes a .NET SDK utility named sn.exe which is an external application.
  3. In order to provide an IOTAProject object, I made a fake class that implemented this interface. This class contains a lot of useless members.

Then I started my refactoring by utilizing IoC pattern. Once you see the source code, you can navigate to this class, Manner20UnsignedHandler, which contains two dependencies I need to inject, an IUser, and an IGenerator. By providing fake objects in unit test, I could resolve the first two issues. However, the third issue became worse, because I provided three fake classes now.


Now came the Mock Framework. Although there is a lot of mock framework available for NUnit, I just simply picked up NMock (because I admire the ThoughtWorkers). I removed all fake classes I created and initialised a few mock objects instead.

What’s the improvement? Even though a IOTAProject instance is mocked, I used only a few lines,

IOTAProject mockProject = mocks.NewMock();
// ....
string fileName = Path.Combine(Path.GetTempPath(), "test.dproj");

In this case I only provided two lines to implement two members used in the test, FileName property and AddFile method.

At last, I could go on to simplify the code and ensure everything is already by asking NUnit the result.

This post is licensed under CC BY 4.0 by the author.

Rhino Mocks vs. NMock

GrapeVine Voice: April 08 Release

Comments powered by Disqus.