When to write test helper code

On the agile-testing list, I answered this question:

So for the first time in many, many years I’m not in a test management position, and I’m writing tests, automating them, etc. We’re using a tool called soapUI to automate our web services testing–it’s a handy tool, supports Groovy scripting which allows me to go directly to the DB to validate the results of a given method, etc. One feature of soapUI is centralized test scripts; I can create helper scripts to do a bunch of stuff–basically, I write the Groovy code I need to validate something and then I often find I’m moving it into a helper function, refactoring, etc.. My question is, how do you know the right balance between just mashing up the automation (ie, writing a script as an embeded test script) vs. creating the helper function and calling it?

Bret Pettichord suggested I blog my answer, so here it is:

I use these ideas and recommend them as a not-bad place to start:

  1. At the end of every half-day or full-day of on-task work (depending on my mood), I’ll spend a half an hour cleaning up something ugly I’ve encountered.

  2. I’ll periodically ask myself “Is it getting easier to write tests?” If it’s not, I know I should slow down and spend more effort writing helper code. I know from experience what it feels like when I’ve got good test support infrastructure—how easy writing tests can be—so I know what to shoot for.

  3. I have this ideal that there should be no words in a test that are not directly about the purpose of the test. So: unless what the test tests is the process of logging in, there should be no code like:

    create_user "sam", "password"
    login "sam", "password"

    Instead, the test should say something shorter:

    using_logged_in_user "sam"

    That tends to push you toward more and smarter helper functions.

    Unsurprisingly, I often fall short of that ideal. But if I revisit a test and have any trouble at all figuring out what it’s actually testing, I use that as a prod to make the extra effort.

What was something of a breakthrough for me was realizing that I don’t have to get it right at this precise moment. Especially at the beginning, when you don’t have much test infrastructure, stopping every twelve seconds to write that helper function you ought to have completely throws you out of the flow of what you’re trying to accomplish. I’ve gotten used to writing the wrong code, then fixing it up later: maybe at the end of the task, maybe not until I stumble across the ugliness again.

One Response to “When to write test helper code”

  1. Kevin Lawrence Says:

    > What was something of a breakthrough for me was realizing that I don’t have to get it right at this precise moment.

    Another approach - to avoid breaking flow - is to write the use the helper methods as though exist and then later, when your test expresses everything it needs to express, go back and implement the helper method.

    You still don’t have to get it exactly right at this precise moment and helps you to think more in terms of what needs to be accomplished than about how you will accomplish it.

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