Software Testing Life Cycle (STLC)

Software Testing Life Cycle (STLC)
Reading Time : 7 mins

We are seeing new software roll out almost every day. It could be a company’s SaaS product or any app for Android or iOS devices. The bottom line, there are a lot of such products on the market and many more on their way. This might make you think it’s an easy job, and not much goes into developing such products. On the contrary, there are a multitude of processes and phases involved in software development. One such phase is the Software Testing Life Cycle (STLC).  

What is Software Testing Life Cycle (STLC)? 

The Software Testing Life Cycle or STLC, commonly referred to as, is a series of test phases to ensure a product/software meets the set standards. After a product goes through the development phase, next is the testing phase. In this phase, some predefined standards are set for the software/product quality, and the testing team analyzes the product against those set standards. 

This process is basically a verification process to check the product quality and make sure that it is free from bugs and ready to release. The Software Testing Life Cycle (STLC) and the Software Development Life Cycle (SDLC) might sound similar but they are not the same. STLC is a part of the SDLC, which is the development process of a product. It’s all about testing the product but in multiple phases. To find out the difference between the two, take a look at this javapoint article. 

One of the crucial things about STLC is the software requirement document, which defines the standards for testing a product. Now, there are a few other terms one should be familiar with when it comes to STLC. These terms include test cases, and entry & exit criteria. Also, there are the deliverables for each phase of the testing cycle.  

The test cases, entry, and exit criteria are applicable for each level of a testing cycle. 

Entry Criteria 

Before starting the testing process, a few essential items/processes are necessary to begin. Once those are met, the entry criteria for an STLC phase are also met.  

Exit Criteria 

It’s the same thing as the entry criteria, except it’s for the exit part of a test cycle. 

Test Cases 

A test case in the software testing life cycle is nothing but a document that contains all the conditions for inputs, executions, desired results, and also the testing procedure. The test is something that is obtained from the Software Requirement Specification (SRS). The shareholders usually share the SRS with the testing team.  

Now that we have covered all the basics in STLS, let us get to the main part, the phases in the testing cycles. 

Software Testing Life Cycle (STLC) Phases

Any kind of STLC has 6 different phases to make sure that the product meets the customer’s requirement. Each phase of this life cycle is to test various aspects of the product. Also, each phase is not always as important as the others and is sometimes avoidable depending on the product testing. Let us see what these phases/steps are. 

  1. Requirement Testing Phase 
  1. Test Planning 
  1. Development of Test Case 
  1. Test Environment Setup 
  1. Test Execution 
  1. Closure of Test Cycle  

A product has to go through these six different phases in the software testing life cycle. We shall now discuss each phase in detail. 

Requirement Testing Phase 

The very first step involved in the testing process of STLC is requirement testing. It’s self-explanatory as to what this phase entails. The testing team will determine all the criteria/requirements for testing every aspect of the software. This is after the testing team collaborates with stakeholders to understand all the prerequisites.  

This phase includes business, architecture & design, and system & integration requirements. Each of these types provides a base for the requirement testing of a product. Apart from understanding the types of requirement testing, testers must also decide on the entry criteria, activities, and the final deliverables. 

Entry Criteria 

This is something we have already discussed, which is the requirement type for testing. Other than that, you also need a requirement specification document to start. 


Here, the activities will involve you making a list of queries to get answers from the other teams and stakeholders involved in this project. It includes defining test types, environmental details, testing priorities, RTM (Requirement Traceability Matrix), and automation feasibility analysis. 


The automation feasibility report, RTM, and the testable requirements are your deliverables in this phase. 

Test Planning 

Test Planning or the Test Strategy is a phase where the team devises a strategy for testing life cycle. This means making cost estimates, resources, objectives, test environment, scope, limitations, and efforts required for the whole project.   

Entry Criteria 

In this phase, all you need is the requirement document. A requirement document is something that contains information in test conditions, parameters, support requirements, etc.


Make a strategy and decide on the type of testing along with a document for the same. Then choose the test tool, estimation of test effort, resources, and the training requirement.   


The deliverables for this phase are various documents on effort estimation and test strategy. 

Development of Test Cases 

The third phase in the software testing life cycle (STLC) is test case development. You already know what test cases are as we discussed in the earlier sections of this article. Well, in this phase, the team works on developing those test cases for the product, along with the test data.  

Once those test cases are done, the quality assurance team checks them. In this phase, the team also works on test scripts and verifies them. The team shouldn’t repeat a test case and the test cases should be based on the end-user requirements. 

Entry Criteria 

It’s the same as the other phases as it needs a requirement document. 


Creation and review of test cases, test data, and scripts. All these need to be clean and easy to understand. Don’t repeat any test cases, and they should cover all the software requirements. 


The resulting deliverables are the test cases, test data, and test scripts. 

Test Environment Setup 

One of the most crucial aspects of STLC is the test environment. Only with the right environment can a team carry out the testing. Here, the test environment means the hardware and software criteria. Most teams carry out the test environment phase after/along with the test case development phase. 

Entry Criteria 

Documents of test cases, test strategy, and test plans. 


The test environments you will see in this phase are the setup of test servers, network, bug reporting, test data for the test environment, and test PC setup. Also, performing smoke tests (checks stability of the built software) on the build. 


Executions, smoke test, and defect reports are the deliverables.  

Test Execution 

You have developed test cases, plans, and scripts, now is the time to execute those things. The testing team will execute the test scripts and perform maintenance for the test strategy.  

Entry Criteria 

Test plan/strategy, test data, and test cases are the entry criteria for this phase. 


Creation, execution, and mapping of test cases. Documents on the results (passed, failed, etc.) of corresponding test cases along with tracking defects. Any defects found are mapped to test cases in RTM (which is also prepared in the same phase). 


Defect reports, the finished execution status of RTM, and also the test case report after execution.  

Since we are talking a lot about defects, you can learn a little more about defect logging from this Tutorialspoint article. 

Closure of Test Cycle  

This is it; you are at the end of the STLC life cycle with this phase. All the results of various phases and processes from the last 5 phases are verified here. Various testing teams involved in the testing process check all the test completion reports and documentation. After this, the team analyzes the whole process in terms of quality, test coverage, time, and objectives met.  

A final report on test closure is also published at the end of this phase. This report is also useful for future reference and helps with improvements in areas where needed.  


Documentation and reports on the project and a final test closure report are generated. A test metrics report based on the cost of the test, the test coverage, quality, time taken, and a few other parameters are also published.   


A test metrics and test closure report are the something you see as the result from deliverables.  


The whole software testing life cycle (STLC) is pretty lengthy and takes a good amount of time. Sometimes teams have to go back and forth to make things right and fix certain issues. Then again, not every team does that. In any case, we have broken all the phases in the testing life cycle into easily digestible information. 

Each phase deals with an essential aspect of software testing as you may have learned by now. Many industries and businesses are employing automated testing to reduce manual work and reduce errors in the testing process. This Test automation article will help you understand why test automation is important, now more than ever. 

That’s why we offer automation, IT solutions, and business solutions to improve businesses and make them reach their full potential. Our expert team of developers can also help you with the testing and quality assurance of a product. All you have to do is hop on a consultation call with us. 

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