Testing

Unit Testing Events And Callbacks In C#

The Problem When you want to unit test a method it’s usually pretty simple. Call the method, pass it it’s parameters and assert against it’s return value, or some other property of the object that may have changed. What happens when a method doesn’t return a value, or update some property? What happens when it leads (perhaps after some delay) to an event firing, or a callback getting called?

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The Anagrams Kata

The following is my C# implementation of the Anagrams Kata as described on cyber-dojo.com Write a program to generate all potential anagrams of an input string. For example, the potential anagrams of “biro” are biro bior brio broi boir bori ibro ibor irbo irob iobr iorb rbio rboi ribo riob roib robi obir obri oibr oirb orbi orib Let’s write a test. [Test] public void NoCharacters() { var expected = new List<string> {""}; Assert.

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Are Unit Tests the new Comments?

It’s verging on heresy to even talk of Unit Tests and Comments as being in any way related. They serve different purposes, work in different ways, and have nothing in common. Except Comments Document Interfaces, API’s etc. Can drive development by writing pseudo code comments first. Mark outstanding work using TODO comments. Explain particularly complicated pieces of code. Context to help future developers avoid breaking the code. Document expectations, side-effects etc.

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Fluent Mocking

Here’s a scenario (for once not a hypothetical scenario, this is a real system I worked on). I was building a wizard based app. To be more accurate I was building lots of wizard based apps. After a couple of wizards the functionality became clear and I extracted it to it’s own framework. My apps could then focus on actual bread and butter functionality. Two of the objects in my framework are ‘Wizard’ and ‘WizardStep’.

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Retrofitting Tests To Legacy Code

One problem with TDD is that those who try it, often begin by writing a few trivial tests to get the lie of the land. Then instead of using TDD to write new code they do something much much harder. They do what I did, they start out by trying to write some unit tests for existing code. Either a past project, or more likely the project they are currently working on.

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