What’s the Difference between Unit Testing and Automation Testing

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As the technologies are getting more advanced, software development projects become more sophisticated. The stiff deadlines and constant enhancement with the new features may quality assurance tasks may be left behind. Here comes the Agile approach that makes the testing part of a software development cycle putting end-users and their experience from using flawless applications first through a thorough process of verification that all the features work as expected.

Here comes the debate between unit tests that are focused on an in-depth examination of code function and automation strategy that comprises through the scripted test scenarios that help to lower the human efforts and speed up the result delivery.

If we try to explain the main differences by analogy a birthday cake will be a perfect example. Unit testing lies in checking that all the ingredients are fresh and suitable for the recipe, while Automation testing is ensuring that its main functions is working as expected: it looks festive, tastes delicious, brings joy, and what is more important is delivered with no delays on the way.

For teams that never worked with automation before it may sound scary mainly due to the myths of price, efforts, and reliability, while in fact they are all dispelled by open-sourced tools for 100% free automation testing, simplified workflows as once a script is written, it can be run with almost no human assistance as many times as it’s necessary. And the last argument for automation is that a script cannot develop a tunnel vision, has no attention issues, and is never tired, ensuring that the result will be delivered with the same effectiveness.

Sometimes unit testing is used as the antonym to the automation one that brings a lot of confusion. Let’s take a closer look at their differences to build a better understanding of their role:

Scope

Automation testing consists of writing scripts to test flows. E.g., a purchase flow, when we are trying to purchase a product through picking it up, adding to cart, and the checkout). The code consists of smaller units for this flow to become possible. A unit testing, as it might be guessed from its name is focused on checking all the units one by one to make sure that they are functioning as expected.

Aim

The main aim of unit testing is to examine every single function to satisfy the proper code quality, while automated testing is focused on the integrity of the flow and match it against the given business requirements ( i.e. entering username and password on the login page should lead you to your account page). One of the benefits of unit testing is that sometimes it may be hard to define the faulty piece of code if the issues are discovered once the whole script is ready.

Actor

Unit testing is performed by developers. It helps them to receive instant feedback on the functionality of their code to know if it’s safe to move further, or it needs to be re-written because the output is different from the desired one. Automation testing is done by quality assurance automation specialists who develop the scalable strategy of the test coverage on the project starting from the small routine tasks to covering all the flows with tests to assess if all the flows serve their main purpose.

Overall, Automation testing helps stakeholders to develop a broader picture of the project quality, which is not possible with unit testing. Even if all the unit tests passed it does not mean that there are no defects in the complex use-case scenarios. The good news is that you don’t need to choose what is better because unit testing can complement automation strategy.  Incorporating unit testing into your test suite is a great way to make sure that nothing is missed and the final product corresponds to the users’ expectations on all levels.

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