The Advantages of Manual Vs. Automated Testing
The question of when and how to use manual and automated testing in the application lifecycle usually has attracted much debate. In general, we follow our existing habits. Teams without a long history in automation are likely to support continued manual testing whenever feasible, while those with the tools and automation experience often attempt to automate everything.
But Q/A teams and developers will tell you that the reality is more nuanced. You need both manual and automated testing. Each approach has its role at different times in the testing practice, and both contribute to the ability of a team to deliver high quality releases. The question is when to use one versus the other? Let’s take a closer look.
Why Manual Testing?
Manual testing provides a way to quickly evaluate a product and provide testers with a familiarity of the features during the development process. Testers create test cases based on their ability to determine whether or not requirements are met. But initially these test cases have to be executed manually, both for the sake of verification of the necessary steps, and also in order to record test scripts for automation in the future.
Manual testing also includes exploratory testing, which enables testers to learn more about the application, while also identifying areas that potentially need more test cases to fully understand weaknesses and risk. Testers use exploratory testing to better understand weaknesses and determine which parts of the application need more test cases.
Lastly, manual testing is especially valuable early in the development of features and the user interface, as layouts and controls are often changing almost daily in response to design considerations and user feedback. It can be more time-consuming to maintain and change automated scripts than to execute tests manually.
From Manual to Automated Processes
Test automation also has multiple roles in the development process. As testers grow more confident in their manual tests, automation saves the time and effort of repeating the same tests over and over again. Recording these tests produces scripts that automated testing tools can execute at any time, often with different sets of data.
Automation brings an important aspect to testing practices. It assures consistency in how a test is performed. Once the validity of a given test is established, automating it provides a defined benchmark of how the test is run on a regular basis. The steps of the test aren’t subject to interpretation by individual testers, and are conducted with the same timings and inputs throughout.
Automation is also essential for regression testing, the practice of executing already-passed tests throughout the development process, to ensure that already-implemented features aren’t broken as development continues. Regressions suites typically contain hundreds or even thousands of tests that can help maintain find issues throughout the development lifecycle.
The Influence of Agile
Agile processes play a role in the debate. Agile requires automation of as much testing as possible, in order to meet the timing requirements of sprints. Recording automation scripts as quickly as they are validated enables an agile team to focus on ensuring new code and features in sprints are afforded the most individual attention.
Of course, automation is a defined practice in both unit testing and smoke testing. Developers typically use an automated unit testing framework such as JUnit or NUnit to perform basic checks on individual parts of their code. And whatever approach the team takes to build and integration, executing a small suite of functionality tests at the end of the process ensures the integrity of the build and provides the team with a known level of quality to begin further work.
Last, automation is essential to certain types of testing. With most types of performance and load testing, it’s simply not feasible to have many users manually exercise an application at the same time. Instead, performance testing tools create virtual users that execute scripts emulating actual activities that the software is supposed to perform. In many cases, teams can use existing functional test scripts as a basis for performance and load activities.
Both manual and automated testing are important parts of any development effort. Knowing when to use each enables a team to leverage the strengths of both in the pursuit of quality, no matter what the methodology or schedule.
As always, leave your questions or comments below.