<Li> User acceptance testing environment, where business stakeholders can test against their original business requirements, </Li> <Li> Production environment, where systems finally get deployed to, for final use by their intended end users . </Li> <P> The 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 the means to rectify defects and validate fixes prior to deployment is incorporated into this phase . </P> <P> The following are types of testing that may be relevant, depending on the type of system under development: </P>

During which phase of sdlc are the test cases developed