Differences Between Retesting and Regression Testing
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Regression testing is a testing method in which every time the previous tests cases are run every time something changesin the existing system to ensure everything is working as it was. Regression testing guarantees that the system is up and running after each updation. Whereas re-testing means testing previously tested test cases again.
Now, you might wonder whether regression testing counts as retesting. Well, they sound similar and they have similarities, but it has different use cases. One fine line that differs one from another is that, in retesting, you know that a bug is there. But in regression testing, you make sure that the test case passes.
Regression Testing
In regression testing, you need to test functional and non-functional test cases. You only need to make sure each and every test case passes and the entire system is bug-free after each updation. If your system is in the initial stage you can expect a weekly release or maybe two times in one week. So, after each release, you need to test each unit plus an integrated system to make sure everything is functional.
It's not feasible to retest all cases manually. If your system has more number of test cases then it will take more time to complete the test cycle, which leads to delays in releases. Eventually, it will become too costly to sustain. Here's an option to make it fast and sustainable: adopt automated regression testing.
In automation regression testing, you can use tools to automate and simplify your regression testing phase. You can automate test cases without worrying about future changes because it is possible to update them once something has changed like data or an environment. Here, no human supervision is needed so you can save both resources and time.
This is a regression testing cycle. Most importantly, if you follow automated regression testing it will be easier to test what has been changed and thus your testing cycle can be completed quickly.
Retesting
Retesting can be done for mainly previously failed test cases to check whether previously found bugs have been fixed or not. This can be similarly done to retest additional softwares and techniques can be used to trackback defects easily.
Let's understand it with the help of an example. Imagine you're releasing the next version for your app by fixing bugs encountered in the previous version. Then the tester will retest test cases that had failed in the previous testing phase. Then it will confirm whether the bugs have been fixed or not.
The need for retesting arises when you want to reproduce a specific bug, when a bug is fixed and the tester needs toconfirm this, or when you want to be double sure about your system.
Difference between Retesting vs Regression Testing
You are right if you are counting regression testing as a type of retesting because in regression testing, you're retesting each case that was tested earlier. Retesting is an important part of testing because it plays an important role in deciding the system's perfection.
Both have many similarities: they are based on repetition, validation, and use black box testing techniques.
Here are a few differences between the two testing methods:
Retesting is mainly used to ensure that a bug has been rectified or not whereas regression testing is used to assure that additional change won't cause any new bugs. Secondly, in retesting, test cases are written for specific parts of the system and only previously failed test cases are executed. Conversely, in regression testing the entire system is involved in the testing and all test cases are re-checked.
Third, retesting is performed when there's a bug, which is expected to be fixed but regression testing is performed when there's a new change in the system. Thus, retesting is done before regression testing because most of the time failed test cases have higher priority. Also, note that regression can be executed parallel to retesting.
Fourth, it's better to automate test cases, to perform faster iterations of the test cycle. Though, you can automate the whole process of regression testing but you can't automate test cases for retesting because the test cases will change after some time. It's better to automate regression testing because the test cases will increase as the system gets bigger.
Retesting is not always considered a part of the testing cycle as it is required only when a tester encounters a bug whereas regression testing is always a part of the process. It should be performed every time a software is about to be released.
In retesting, the tester doesn't need a new environment setup because it uses the same environment as the previous test cases. However, regression testing might require a new environment setup if some additional changes in data or test cases.
Conclusion
You need to go as per your test plans. You might require both options for better product quality. Regression with automation will definitely help you achieve higher test coverage in lesser amount of time and with lesser effort. Many automation testing tools are available in the market. You need to choose the tool that matches your requirements best. Retesting generally is performed before regression testing to analyze defects thoroughly. In some cases, it can be done parallelly.
