Which steps of SDLC do you think can spoil the complete base of the project . Elaborate the importance of that step?

I think ‘testing’ phase of the SDLC is important which can spoil the base of the project because it is the phase where the
actual code is tested at various levels in software testing. Unit, system and user acceptance testings are often performed.
This is a grey area as many different opinions exist as to what the stages of testing are and how much if any iteration occurs. Iteration is not generally part of the waterfall model, but usually some occur at this stage. In the testing the whole system is
test one by one

Following are the types of testing:

* Defect testing the failed scenarios, including defect tracking
* Path testing
* Data set testing
* Unit testing
* System testing
* Integration testing
* Black box testing
* White box testing
* Regression testing
* Automation testing
* User acceptance testing
* Performance testing

Following are the major advantage of testing in SDLC

  1.  Identification of bugs and defects: Testing phase is one phase that determines the bugs and errors in the application. These bugs can be at unit level or system level. With so many testing phases, you get to keep away from any kind of bugs that may be affecting your application.
  2.  Information to stakeholders and reputation of company: With the help of testing phase, it helps you to know the state of product and service quality. The stakeholders get good information through testing phase about service quality too.
  3.  Improvement in product quality: As testing is a phase that helps in knowing the actual outcome and the expected outcome. Surely, it can help you to improve your product quality. With proper testing done, you come out of errors and develop perfect software application for the users.
  4.  Technical importance: In any SDLC lifecycle, testing phase is important for technical aspect, as it has to come out with best technically sound application.
  5.  To get ahead of any competitive developers: Perfect testing tools and methods help you and your application to grow up in market and keep away your competitors. With getting away in all phases of testing, you develop more sound, safe and secure software application.
  6.  Keep away any hazards: When you develop any software, testing plays an important part. When you give your software without any testing then it may be hazardous to the users who are using it. To keep everyone away from any hazard, it is necessary that you go under all testing phases.
  7.  Improved quality: Proper tested software gives you more confidence of coming up with great software. Secondly, it improves quality of your software application as continuous and all kinds of testing modes have made a secure and safe application that can be used by the end users.
  8.  Verification and validation: One of the main aims of testing phase in SDLC is for verification and validation. Testing is a phase that can serve as a metrics as it is used heavily in V&V method. Based on the result, you could come out with comparison between qualities amongst different products.
  9.  Reliability estimation: This is yet another important factor that is determined by the testing phase. If your software application has gone through all small level like unit testing and major testing like regression testing and all, then sure it is a reliable application. Hence testing determines reliability of your software application. Testing may serve as the best statistical method that defines operational testing on application resulting in a reliable software product.
  10. Economic importance: A well-tested software application will have good economic impact. This is because any one would love to go with reliable and trusted application in market.