A product's stages of development are referred to as the product life cycle (PLC). There is considerable work involved in getting a product through its PLC. Software testing at many companies has matured as lessons have been learned about the most effective test methodologies. Still, there is a great difference of opinion about the implementation and effectiveness of automated software testing and how it relates to the PLC.
This is where the PLC comes in. How effectively you make use of the PLC will often be dependent on your programming resources and the length of the PLC. Companies large and small struggle with software testing and the PLC. Hopefully, this discussion of the PLC should help you determine when to use automation and when manual testing is preferred. This should help you answer the questions: "Why should I automate my software testing?" "How can I tell if automation is right for my product?" "When is the best time to develop my test software?".
The Product Life Cycle
As we discuss the use of automated and manual testing, we need to understand what happens in each phase of the product life cycle. The PLC is made up of six major stages, the Design Phase, the Code Complete Phase, the Alpha Phase, the Beta Phase, the Zero Defect Build Phase, and the Green Master Phase. You can think of the PLC as a timeline showing the development of a software product. These are the major milestones that make up the Product Life Cycle. Products that follow these guidelines for implementation of the PLC will have a much better chance of making it to market on time.
The implementation of the PLC varies widely from company to company. You can use this as a guide for future reference to assist you in your automation efforts. Your implementation will vary from the ideal PLC that is discussed here, but your software's success may depend on how well you've implemented its PLC. If your PLC is to include automated testing you should pay attention to which automated tasks are performed during each phase.
For each phase we'll describe it, define its special importance and discuss how to incorporate software automation into your project. Most other discussions of the PLC don't include the lessons learned about test automation. This should be your "one-stop" guide to help you know how and when automation fits into the PLC.
Design Phase
What is the Design Phase? The design phase begins with an idea. Product managers, QA, and Development get together at this point to determine what will be included in the product. Planning is the essence of the design phase. Begin with the end in mind and with a functional specification. Write down all of your plans. What will your product do? What customer problems does it solve?
Incorrectly, some companies don't include Quality Assurance (QA) in the design phase. It is very important that QA be involved as early as possible. While developers are writing code, QA will be writing tests. Even though QA won't really have the total picture of the product, they will want to get as much of a jump on things as possible. Remember, that the primary purpose of QA is to report status. It is important to understand the product's status even early in the Design Phase.
Automation Checklist
If you answer yes to any of these questions, then your test should be seriously considered for automation.
Can the test sequence of actions be defined?
Is it useful to repeat the sequence of actions many times? Examples of this would be Acceptance tests, Compatibility tests, Performance tests, and regression tests.
Is it necessary to repeat the sequence of actions many times?
Is it possible to automate the sequence of actions? This may determine that automation is not suitable for this sequence of actions.
Is it possible to "semi-automate" a test? Automating portions of a test can speed up test execution time.
Is the behavior of the software under test the same with automation as without? This is an important concern for performance testing.
Are you testing non-UI aspects of the program? Almost all non-UI functions can and should be automated tests.
Alpha Phase
What is the Alpha Phase? Alpha marks the point in time when Development and QA consider the product stable and completed. The Alpha Phase is your last chance to find and fix any remaining problems in the software. The software will go from basically functional to a finely tuned product during this phase.
Automation Activity During The Alpha Phase
At this point you have done the tasks that need to be done in order to reach Alpha. That is, you have all your compatibility, interoperability, and performance tests completed and automated as far as possible. During Alpha you'll be running breadth tests every build. Also you'll run the compatibility, interoperability, and performance tests at least once before reaching the next milestone (beta). After the breadth tests are run each build, you'll want to do ad hoc testing as much as possible. As above, every bug should be associated with a test case to reproduce the problem.
Beta Phase
What is the Beta Phase? The product is considered "mostly" bug free at this point. This means that all major bugs have been found. There should only be a few non essential bugs left to fix. These should be bugs that the user will find annoying or bugs that pose relatively no risk to fix. If any major bugs are found at this point, there will almost definitely be a slip in the shipping schedule.
Automation activity during the Beta Phase
There's no more time left to develop new tests. You'll run all of your acceptance tests as quickly as possible and spend the remaining time on ad hoc testing. You'll also run compatibility, performance, interoperability and installer tests once during the beta phase.
Zero Defect Build Phase
What is the Zero Defect Build Phase? This is a period of stability where no new serious defects are discovered. The product is very stable now and nearly ready to ship.
Automation Activity During The Zero Defect Build Phase
Run regression tests. Regression testing means running through your fixed defects again and verify that they are still fixed. Planning for regression testing early will save a lot of time during this phase and the Green Master phase.
Green Master
What is the Green Master Phase? Green Master is sometimes referred to as the Golden Master or the final candidate. The product goes through a final checkout before it is shipped (sent to manufacturing).
Automation activity during the Green Master Phase
After running general acceptance tests, run regression tests. You should run through your fixed defects once again to verify that they are still fixed. Planning for regression testing early will save a lot of time during this phase.
For details read here