Exploration Through Example

Example-driven development, Agile testing, context-driven testing, Agile programming, Ruby, and other things of interest to Brian Marick

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Fri, 09 Apr 2004

"Bang!" went the ColumnFixture

Part of a series on FIT extensions and stylistic tricks.

ColumnFixtures are useful when you want to vary data a lot but vary processing not at all. Having each row be a separate test is very tidy.

Sometimes the sequence of events is this:

1. provide data (which varies)
2. do something that changes state (always the same thing)
3. check that the state was changed correctly (always the same way)

Now, it's not hard to use the second type of column for that: just have the state-changing method return some random value, like true, and have FIT "check" for it. Here's an example:

Still, it bugs me that there's no visual cue that calculate isn't something different from sum. So, taking a leaf from Scheme, I propose that columns used for side-effect be distinguished by ending their name with "!". This eliminates the need for anything to be in the column cells, which visually separates the input from the expected results:

I have written a version of ColumnFixture that makes the above test pass. (Here's a zip file that includes it, the test, and the test source. If people want me to, I can include it in my StepFixture jar file.)

This version of ColumnFixture does one other thing. I like space-separated names at the heads of columns, so I added code to "camel case" them. (That is, in the test, "number 1" names method number1. And "do calculation" would name method doCalculation.) To my mind, this makes ColumnFixture consistent with ActionFixture.

## Posted at 16:58 in category /fit [permalink] [top]