There are many reasons for Agile teams to automate their tests besides the knowledge that everyone else is doing it.
Manual Testing Takes Too Long
This is the most basic reason for an Agile team to automate their tests. Manual testing and regression cycles simply take too long to complete in an environment that does not provide the same testing time as traditional software development methodologies.
As an application gets bigger and more complex over time, the test matrix grows larger and larger, and the team does not have time during the sprint to manually complete the regression tests needed to meet the highest quality standards.
Running a full regression suite manually during a sprint is just bad practice in an Agile environment. If your current practices do not contain any automation coverage, start now.
Manual Testing Leads to Technical Debt
If you execute your regression tests manually, you already know that it takes a huge amount of time. In addition, it is common practice for Agile teams to run regressions every day, or at least every sprint, which cannot be done manually.
Executing regression tests manually does not allow the team to keep pace with coding. Then programmers must free up their time to help with the testing, which leads to technical debt and increases frustration in the team.
Automation Techniques Improve Team Knowledge
Using advanced techniques such as Test-Driven Development (TDD), where code tests are written before the actual code, allows programmers to gain a deeper understanding of the requirements, design, and architecture of the product.
Automated Tests Provide Fast, Early and Frequent Feedback
If there is no change in the automated test script, we can expect it to pass until the functionality of the application is changed. When a programmer modifies the application code, she should also maintain the automated tests to accommodate the change.
If the automated script was changed to support the code changes, and the tests still fail, a regression bug may have been introduced with the code modification. This is a great indicator of the efficiency of the automated test design.
Another thing to know is that running an automated suite of tests for all new and modified code that is checked-in ensures that regression bugs are caught at an early stage. Bugs caught early are cheaper to fix and do not add as much risk as in advanced phases of the development process.
When the bug is found early (minutes to hours from when the programmer adds the code), the change is still fresh in the programmer’s mind and is therefore easier to troubleshoot than it would be days later, during the manual testing process.
Automation as a Key Factor for Stable Builds
Due to the nature of Agile development, it is important that the team not spend their already limited time on unwanted problems such as partial or corrupted builds that prevent them from finishing their work.
Partial or corrupted builds are one of the top time consumers during Agile development. There is no way that the team can succeed in delivering their commitments without having an automated CI/CD system that allows them to have stable builds throughout the sprint.
Automation Helps Free Up the Team’s Time
Test automation takes time, and there is more time spent on maintenance, but once the team succeeds in creating the greater portion of this system, it reduces the time spent on executing manual test scripts, running numerous repeatable tests and endless manual regression cycles.
Now that the team has reliable automation that can replace the manual execution of regression cycles, they have the energy and time to focus on new test scenarios and learning more about the product and how it works, which increases the overall quality of the team’s deliverables.
Automated Regression Tests as a Safety Net
Knowing that the code has sufficient test coverage by automated regression tests gives the team confidence when modifying or adding code. This confidence is not a small thing in the Agile development process, where new code is checked-in and tested daily.
Automated regression tests provide the team with a safety net that helps them find unexpected bugs caused by the newly added or modified code within minutes (for a unit, component, and integration-level tests) or hours (if at a higher functional level, such as system or end-to-end tests).
If the team doesn’t invest their time in building a solid automated suite of tests at all levels of the application to act as a safety net, the programmers will start to treat the testers themselves as the safety net, which leads to mini-waterfalls in the development process.
Teams that have good coverage from automated regression tests can work in a more reliable environment that allows them to write their code and add it to the main branch fearlessly, because they do not need to wonder how this new code will break the build and what hidden bugs may arise. The tests will tell them very quickly whether they broke anything.
Manual Processes Are More Vulnerable to Human Error
Manual processes and manual testing are more vulnerable to human error. That's just a simple fact. Manual testing is a repetitive process that gets very boring for a team member who needs to follow the same test scripts over and over again.
And when people get bored, stupid mistakes are more likely to happen, obvious bugs are overlooked, test scripts are not executed as they were the first time, and people cut corners to complete work when facing tight deadlines.
The simple solution is to automate all tests that contribute to the team ROI from sprint to sprint. The direct result is the reduction of human error, risk mitigation, and creating a constant development process that increases the efficiency of the team.
Consistency is achieved once the team automate processes (testing included), reducing the possibility of human error because each process and test is done in exactly the same way each time. Automated frameworks do not cut corners to achieve deadlines.