Full Software Testing Life Cycle (STLC): Everything You Need to Know

Why testing is important in the software development life cycle

The global software testing market surpassed $40 billion in 2020 and is expected to grow at a CAGR of 7% from 2021 to 2027 according to Global Market Insights. In 2022, as the products become more complex, using AI and machine learning, QA becomes even more important. 

Quality assurance used to be overlooked by software developers. After they understood its importance, a common practice was to test the whole product after it was fully developed. Currently, the rules have changed, and businesses are ready to invest in software testing and quality assurance services.

Quality assurance used to be overlooked by software developers. Even now clients are sometimes hesitant to invest in it properly, but QA and testing is paramount for a software product’s success

Iryna Nema, Lead QA at Mobindustry

Businesses’ revenue and reputation depend now on the quality of their software, so quality assurance has to be prioritized. At the same time, the software world changes so fast, that businesses can’t afford to spend weeks on QA and redoing the whole project after it’s already been developed. 

The Agile approach to quality assurance as well as custom mobile app development services has become widespread because it allows to solve issues gradually and avoid large inconsistencies in complex products. Each piece of software that’s being developed, is immediately tested. The processes of development and QA have become standardized, and are now deeply integrated with the Agile methodology. 

In this article, you’ll learn about the software testing life cycle, its components, software testing phases, and best practices. I’ll explain the software testing life cycle in Agile and the changes it makes in the stages of software testing life cycle.

What is the software testing life cycle?

The software testing cycle is a chain of tasks and activities that are created to analyze the current state of software, check its compliance with the requirements and build a plan for its improvement. 

In which phase of the system life cycle is software testing performed? As I already mentioned, previously a quality assurance lifecycle happened at the end of the development process, just before the release. However, as software became more complex, and the requirements for its quality became more strict, the logic of STLC in software testing evolved as well. 

Now, the code must go through many regular QA cycles at each stage of software development: companies don’t wait for the whole product to be ready to test it. Rather, they test it in batches and use these methods to optimize the repeating testing cycles:

• Test automation
• Crowdtesting
• Test-driven development
• Shift-left testing
• Shift-right testing

An efficient QA life cycle that is repeated during the development leads to high code quality and reliability because it avoids the global issues developers often encounter when checking software after it’s fully developed. 

With STLC, you get a usable, well-performing product that is in line with your requirements. Thus, it brings you more customer satisfaction, and consequently more revenue. 

So, what are the steps in the software testing life cycle?

Main phases of Software testing life cycle

Every software QA life cycle has six main phases:

1. Requirement analysis
2. Test planning
3. Test case development
4. Test environment setup
5. Test execution
6. Test cycle closure

All these stages have their own parameters that include:

• Entry criteria — are all the tasks and items that should be completed before the testing begins. 
• Exit criteria — includes all the items that need to be present before the testing can finish
• Deliverables and Activities — items on a project like features, particular functionality, elements of code, and also tasks, for example, code review

In the perfect world, you should never start the next phase before the criteria for the previous phase are met. However, in the real world, it doesn’t always happen like this, so you need to always consider these risks when planning your QA process.

Let’s now talk in detail about all the phases of the testing life cycle and describe the activities and deliverables for each phase.

Requirement analysis

Every development project should start with requirements. At Mobindustry we extract them at the discovery phase of a project, where we talk with our clients about their business processes, goals, objectives, and expectations. The requirements document contains business needs, architecture, features and functionality, technologies, system requirements, target devices, functional and non-functional specifications, and even a list of stakeholders and people responsible for each stage of the project.

Everything on this list that can be tested, must be checked by quality assurance specialists. Usually, they create their own QA documentation on top of technical specifications, where they define their activities and requirements. While creating this document with a strategy, the QA team brainstorms and identifies blind spots. If they lack requirements, the team should clarify them with business or engineering stakeholders.

At this stage, the QA team with the stakeholders decide if it’s feasible to automate quality assurance. Most large and complex projects benefit from automated testing because of the high volume of repetitive tasks. 

Let’s talk about the activities and deliverables of the requirement phase.

Activities:

• Identifying types of tests
• Gathering requirements and prioritizing them
• Preparing a Requirement traceability matrix (RTM)
• Analyzing the feasibility of automated testing
• Defining the strategy and environment

Deliverables:

• RTM
• Automation feasibility report (optional)

Test planning

At this stage the QA team gathers all the requirements they collected during the previous phase and creates documentation that defines the QA strategy. 

At this point project managers are involved as well: they review all the available resources for quality assurance and create a plan based on their abilities. The test plan document defines all aspects of the future stages of this testing life cycle.

The main goal of the QA plan document is to connect the departments, organize and plan the work of QA specialists, and help all members of this process communicate. For example, developers who will create unit tests and provide bug fixes after the testing will benefit from the documentation, as it defines the requirements and criteria for acceptance.

What does the test plan cover exactly? Here are its contents:

• Functional tests
• Non-functional tests
• Automated and manual tests
• Details of the test environment
• Roles and responsibilities of QA team members
• Timeline
• Deliverables

Activity:

• Preparation of a test plan document
• Tool selection
• Test effort estimation
• Resource planning
• Determining the roles and responsibilities

Deliverables:

• Test plan or strategy document
• Effort estimation document

Test case development

A test case is a detailed description of each test that needs to take place. It’s usually created by the members of a QA team and is used as an instruction for each test scenario. 

QA specialists create test cases on a basis of a test plan that contains all the requirements. The main goal of a test case is to create a plan for validating each requirement and figure out which strategy will be the most suitable for each test case. 

A test case should have the following qualities:

• Clear and simple, so that every team member can easily understand them
• Unique, so that they are different from each other
• Covering the requirements fully, so that core functionality is tested from all aspects
• Repeatable, so that these tests can run over and over again as the functionality changes
• Not altering the test environment, so that future tests can run smoothly when different software configurations are being validated

Note that test cases may need maintenance and updates, as your product changes and evolves. New functionality and requirements should be validated, so each time you go through the software testing life cycle, don’t forget to check your test cases and update them if needed.

Peer review from team leads and other QA specialists is the best way to make sure your test cases cover the requirements fully. At this stage, your QA team should also check and update the automated test scripts, if you have any.

Activities:

• Creating test cases and test automation scripts
• Reviewing test cases and scripts
• Creating test data

Deliverables:

• Test cases and scripts
• Test data

Test environment setup

Now that your team has a plan and test case scenarios, it’s time to prepare an environment where quality assurance will occur. At this stage, QA specialists need to consider all parts of the environment that including:

• Hardware
• Software
• Frameworks
• Configurations
• Network
• Test data
• Bug reporting capabilities
• Architecture

All these factors determine the quality assurance environment. It’s also important to consider users, their devices, and preferred operating systems. For example, if your future product is targeted toward iOS users, it’s important to include Apple devices and the Safari browser in your QA environment.

Note that the test team doesn’t define the environment: it’s done by the development team. The QA team performs smoke testing. Smoke testing is what helps to check the environment before quality assurance takes place.

Activities:

• Define the requirements for architecture, software, hardware, and environment
• Prepare the requirements list for the test environment
• Set up the environment and test data
• Do smoke testing in a suggested environment

Deliverables:

• A ready environment with test data
• The results of a smoke test

Test execution

Now it’s time to fully test your software by running all the test cases one by one and executing both functional and non-functional tests. At this stage, testers will document all bugs and inconsistencies they found, so that later they can give these bug reports to developers for fixing. 

After developers fix the code and make necessary changes, QA specialists will often perform the tests again to check if all requirements are now met and if changes didn’t affect other parts of the code negatively.

The main risk during this stage is the test overload when you have too many tests to do. This usually happens in large projects, and automated tests help to avoid this situation while also accelerating the whole quality assurance process.

Activities:

• Execute tests according to the plan
• Document the results of the tests and create bug reports
• Map bugs and defects in the requirement traceability matrix
• Retest the software after the fixes
• Track the defects until they’re fixed

Deliverables:

• Completed requirement traceability matrix
• Updated test cases
• Bug reports

Test cycle closure

This is the final stage of a software testing life cycle, and its main goal is to finalize the quality assurance process, provide reports and find valuable insights about the testing and development process.

The report at this stage usually contains a summary of QA activities and their results, as well as an analysis of the quality assurance process. The report also includes all the documentation that was generated and gathered during the testing life cycle. This includes the test plan, test environment, test cases, and results. Any unusual behavior of the software that the team noticed during testing should also be reported.

Now it’s possible to plan the further acceptance and customer representative review of the product. After this, it’s time to release the software.

The discussion after the test life cycle is a very important part of the whole development process, as it allows team members to explore their current strategies and their efficiency. Each time a testing life cycle takes place, a team should make conclusions and suggest improvements for future cycles.

Activities:

• Evaluate the whole STLC based on its goals, time it took, cost, coverage, resources, business objectives, and quality
• Define test metrics based on parameters mentioned above
• Document the conclusions
• Prepare a test closure report
• Discuss and analyze the test process to identify processes that could be improved next time
• Prepare a report of the product quality for a customer

Deliverables:

• Test closure report
• Test metrics

These are all stages of the full software testing lifecycle. As you can see, it requires meticulous preparation and analysis that affects the next cycles of development and quality assurance. Does it remind you of anything? Waterfall development works according to the same principle, that’s why STLC works well with this approach. 

However, the Agile approach to development is more popular among businesses nowadays, as it allows for more flexibility. How does STLC work in an Agile environment? Let’s find out.

Application of STLC in Agile development

The phases of the software testing life cycle I described in this article are sequential, meaning that they follow each other just like during the waterfall model of software development. What does STLC look like in an Agile environment, and is it possible to adapt it to this approach?

Of course. If the quality assurance team works according to the Agile methodology, the software development testing phases may look a bit different. For example, STLC in Agile suggests that the reporting at the end of the QA cycle may be omitted — instead, the release will just be planned for delivery. 

Software testing life cycle in Agile focuses on shift-left and shift-right testing. This allows to notice and eliminate any bottlenecks.

Shift-left testing is focused on finding and fixing bugs as soon as possible. It’s widely used in CI/CD, and includes gathering requirements, writing unit tests, and creating functional, integration and service tests. According to this type of quality assurance, the tests should be executed as soon as possible during the sprint. This approach allows developers to fix bugs fast and minimize the number of defects before the release.

Shift-right testing focuses on user feedback, A/B testing and other types of tests like security and performance testing. This approach allows developers to get direct feedback from users, test UI and ideas for features, and make changes according to the market requirements and expectations. 

As you can see, STLC phases may change according to your development and testing approach. Agile quality assurance accelerates the STLC, reduces the planning stage and allows developers and testers to make decisions based on hard data, market response, and current business needs.

Final thoughts

Full software testing life cycle is one of the most popular approaches to testing software, and although it can be slightly different based on your unique project, needs, and also methodology, the main steps of STLC usually remain the same. 

Your first and most important step in both software development and its testing is gathering requirements. At the initial stages of a project, this usually happens during a discovery phase. However, in Agile development, you’ll need to regularly review your requirements and change them according to your current business needs and the market response. 

Your first and most important step is gathering requirements. In Agile development, you’ll need to regularly review your requirements and change them according to your current business needs and the market response.

After the requirements have been defined, it’s important to create a test plan and test cases. Remember, that all of this should be thoroughly documented so that all team members are on the same page. 

If you follow the Agile methodology, plan your quality assurance activities within sprints, and test software as it is being developed. This means, that each small functionality that has been created, should be immediately tested. This will help you minimize the inconsistencies on the project before the release, and save you time and money on testing.

If you’d like to test your product, or you’re looking for a vendor with strong quality assurance culture, you’ve come to the right place. Don’t hesitate to contact us, and we’ll develop a perfect testing and development strategy for your business project.

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