Sunday, 29 July 2012

Simple BDD

I have spoken before about how much I like the fluent-interface. I use it a lot expecially with object builders. I was looking at the Bddify framework. I have known about this style of testing and BDD for a while, but was really inspired about how Bddify write tests.

I realized that I could do this so easily with everyday tests as well without the need for any fancy frameworks etc. And just make my own tests easier to write and understand.

I was doing a very simple schedule for an import process and heeding the warning by Ayende about scheduling. I tried to consider the wise words and established that my requirement is very simple and to the point and most of these won't be a problem for me. With this in mind I wanted to make sure there are no bugs in the schedule logic so this is what I came up with. First I could express my requirements in the test:

The implementation of this is very simple and I have just done so directly in my test class. It's just about the grammar Given a set of inputs When certain conditions are met, Then we can expect a specific result.

  • Given - Construction of the objects I am testing.
  • When - Setting some criterea on the objects I have created.
  • Then - Run a method and (Act and Assert)

Obviously to have a good grammar you first need to understand a bit more about your domain and tests. And what you will be testing, so when starting I still write the first test or 2 using a few variables and seeing how the test logic fits together and create my grammar from there.

Bugs with these kinds of things could be a nightmare in a live environment. So this style of testing helps you build all of the scenarios that you can think of and make sure those work through the lifetime of the solution.

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