Functional testing allows developers to verify that the software is performing as expected, when used by any user or system that interfaces with it. It includes unit, integration, sanity, regression, and usability tests. The entire range of these tests provides a dependable basis for ensuring the stability and progress of a software system.
In a traditional development model like the Waterfall model, the testing of the system usually starts once the development is completed. However, in agile development, the software is developed and tested simultaneously in sprints, and incremental updates are rolled out in each cycle.
In an agile model, while the software developers are working on building the software, the testers perform functional testing to ensure that the existing functionality isn’t affected due to the newly introduced changes. The most common functional tests performed include smoke, sanity, unit, component, regression, etc.
In this article, we will discuss the significance and strategy of functional testing in an agile environment, along with some key points to consider while planning testing scopes 
The significance of functional testing in agile
Following the agile testing methodology leads to 3 things- improved quality, faster delivery and a happier team:
Improved quality
Since the agile testing methodology allows for continuous feedback, bugs in the software are identified much earlier in the development lifecycle 
Moreover, since the testers get more time to thoroughly test each software version, they also get time for sanity testing, and regression issues are likely to be avoided. Also, following this approach allows the developers and testers to work in parallel, and leads to maximum resource utilization.
Faster delivery
In a Waterfall model, the actual release could take months, often leading to irrelevant features being delivered to the customers. With agile testing, not just the development cycle is shortened, but also the customer feedback is received frequently. This in turn helps to deliver relevant features at a faster pace.
Happier team
Agile environment automatically leads to close interactions between developers, testers, project managers, and product managers, which makes work more enjoyable and builds a productive workplace.
Agile strategy for functional testing
It is important to have a well-defined approach for test planning, execution, and analysis to ensure high product quality 
In this section, let’s go over some key steps in an agile functional testing strategy:
Requirements gathering
The first step before your team can begin testing is to gather clear and complete test requirements. The business team or product managers could arrange presentations explaining the features in the next release cycle to bring the team up to speed with the requirements. Moreover, it is important to track requirement changes so that the test cases, test plans, etc. can be updated accordingly.
Test planning
Once the requirements are finalized, the first task for the testers is to come up with a test automation plan, and decide what should be tested and what should be left out. Also, the testers should come up with traceability matrices to ensure that there are no gaps in the test plan and the product requirements.
Strategy & execution
The next step in software testing in agile is to formalize a strategy for testing, so that optimum test coverage can be achieved. This phase also includes verification of the test environment and configuration, to ensure that the test execution could take place smoothly.
Moreover, testers also need to plan critical areas to be focused on while testing the software for the next release cycle. Once the strategy has been formalized, the testers can proceed to the test execution phase which takes up most of the sprint time 
Defect management
The way that bugs are reported back to the developers plays a key role in the overall productivity of the team. It is critical that bug reporting happens in a clear form, that the description is self-explanatory and that the steps to reproduce the bug are clear. Moreover, the testers should be able to track its status until it’s resolved.
Reporting & metrics collection
Finally, test reporting and metric collection should be easy to comprehend and should be done in a standard format so that all the stakeholders can make use of. It should clearly state the status and quality of each product feature so that the business team can take a call on releasing the product or postponing it to the next sprint.
Conclusion
In this article, we discussed the significance of functional testing in an agile environment, so that a high-quality product can be shipped to the customers at a fast speed, and while ensuring that the team is contented.
In addition to that, an extensive test suite provides confidence to the development team to ship products without worrying about production issues. At the same time, it also provides confidence to the business team, that there is no gap between the software requirements and the shipped product 