Skip to main content

Importance of Unit Tests

Anyway I'm writing a post on creating my first set of unit tests by myself for a small console app that a colleague created, and I thought to lead up to it I'd write a brief post explaining the importance of unit tests, why they're important and how they can make our lives as QA easier.

 Wikipedia defines Unit Testing as "unit testing is a method by which individual units of source code, sets of one or more computer program modules together with associated control data, usage procedures, and operating procedures, are tested to determine if they are fit for use". So essentially, in everyday terms, it's the smallest possible piece of testable code.

 Some people would argue that unit tests are a developers task, but I feel being the first form of QA on the code, that it's only right that as a QA you should play some role in coming up with then. Now you don't have to be able to write the unit tests, but at the very least you should sit down and come up with the scenarios, and maybe even pair program on writing the tests, if that's what floats your boat. 

 The overall driving factor behind unit testing is that it's cheaper to fail fast and early, the cost of fixing a bug increases exponentially the further down the development cycle it's found, with Unit Tests they give you instant feedback when a test fails.
If a unit test fails it's often easy to debug and quick to see why it failed, even better if the unit tests are run at check in and fail the check in if any unit tests don't pass, this way it encourages developers to code better, and to make sure that unit tests are passing and testers only ever see good quality builds being deployed, and time isn't wasted sitting around waiting for a working build.

 Unit Tests are quick and easy to run and maintain, unlike UI tests, they aren't brittle, they don't rely on interacting with a User Interface. Unit tests ensure that the code does what it is expected to do, whereas acceptance tests ensure that the application does what the business/users expect it to.

 It's also important to get involed as a QA in coming up with scenarios in unit tests, often if a test is covered by a unit test then it might mean there isn't a need for an acceptance test to be written and run(obviously this is very much specific to the codebase etc).

Labels:

Comments

  1. Srinivas Kadiyala9 May 2013 at 03:32

    What does Programmers dont want to write Unit Tests ?

    ReplyDelete
    Replies
    1. Gareth Waterhouse14 May 2013 at 02:21

      Good point. I think you should try and educate them, and the business. Often it's not developers who don't want to write unit tests, but time constraints stopping them from writing them. If you can convince the business and the developers of the value in spending that little bit longer writing unit tests, the benefits will be tenfold.

      Delete

Post a Comment

Popular posts from this blog

Treating Test Code as Production Code

It's important when writing automated tests to remember that the code you write should be up to production standards, meaning any conventions that you have in place should be adhered to and that it should follow good design patterns. Too many people often say why does it have to be as good as production code, it's "Only" a test, so long as it passes then that's fine... To answer this we need to look at why we want our tests to be written in such a structured and efficient manner: - Maintainability - by making the test code structured and efficient, it becomes far easier to maintain and in doing so changes in the future can happen quickly as the test isn't linked to anything that it shouldn't be and it's easy to understand for a new set of eyes. - Durability - Again by making the tests structured they should be resistant to changes, if you change a variable name for instance then it shouldn't effect the unit test unless it absolutely has to....
1 comment
Read more

Testers: Be more like a Super-Villain!

Who doesn't love a Super Hero? Talk to my son, and he'll tell you how much he loves them, talk to many adults and they'll say the same! Deep down, we all love to be the Super Hero, we all want to save the day! However, I want to talk about the flip side of Super Heroes, the Super Villains... I often play Imaginext with my son, and I (unfortunately?) am nearly always the Super Villain! Be it Lex Luthor, Joker, Two Face, Mr Freeze or The Riddler! These are all great characters and great Super Villains, but why would I want to write about Super Villains? A while ago where I worked, we had a few Super Heroes, people who would be able to come in and "fix" things that had broken and help deliver projects on time. We then shifted, we decided to do away with the Super Hero culture and try and prevent from being in that position in the first place, whilst we didn't go as far as wanting to hire Super Villains, it's definitely a story that has stuck with me and t...
2 comments
Read more

Using BDD and gherkinising your Acceptance Tests

In my post Testing of Automated tests , I mention about a BDD framework which involves using BDD to drive your acceptance tests. BDD stands for Behaviour Driven Development.  One effective method of writing BDD tests are by using a format known as Gherkin language. These consist of Given, When, Thens. The main advantage of the gherkin language is that it's readable by the business, and in an ideal world forms part of the Conditions of Acceptance around a PBI. Also, using a Visual Studio plugin of SpecFlow , you can integrate your Gherkinised COAs into your solution with feature files, and then drive the automated tests, however, for this post I will focus solely on how to effectively gherkinise your acceptance tests. A Feature file consists of a feature outline, which details what the feature file is testing followed by Scenarios and examples (parameters).  The BDD scenarios are made up of a Given, When, Then... These are effectively an initial state (Given), an action (W...
6 comments
Read more